Annals of Oncology Advance Access originally published online on February 23, 2006
Annals of Oncology 2006 17(5):818-826; doi:10.1093/annonc/mdl016
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2006 European Society for Medical Oncology
Benefit from adjuvant tamoxifen therapy in primary breast cancer patients according oestrogen receptor, progesterone receptor, EGF receptor and HER2 status
1 Academic Department of Biochemistry, The Royal Marsden NHS Trust, London; 2 Clinical Trials Group of the Department of Surgery, Royal Free and University College Medical School, University College London, London; 3 University Department of Surgery, Bristol Royal Infirmary, Bristol; 4 Clinical Trials and Statistics Unit, Institute of Cancer Research, Sutton, Surrey; 5 Department of Surgery, University College, London; 6 The Portland Hospital, London, UK
* Correspondence to: Dr M. Dowsett, Academic Department of Biochemistry, The Royal Marsden NHS Trust, Fulham Road, London SW3 6JJ, UK. Tel: +44 (0)20 7808 2887; Fax: +44 (0)20 7376 3918; E-mail: mitch{at}icr.ac.uk
 |
Abstract |
|---|
 Top Abstract introductionmaterials and methodsresultsdiscussionReferences |
|---|
Background: Most women with oestrogen receptor (ER) positive primary breast cancer receive adjuvant tamoxifen after surgery. The measurement of tumour biomarkers should allow better selection of patients for such treatment or for therapies such as aromatase inhibitors.
Patients and methods: Histopathological blocks of primary breast cancer patients who had been randomized to receive 2-years tamoxifen or no adjuvant therapy in two mature randomised clinical trials were retrieved. Immunohistochemical staining for ER, progesterone receptor (PgR), HER2 and epidermal growth factor receptor (EGFR) was undertaken. The primary endpoint was relapse free survival.
Results: 813 patients were included in the study. Benefit from tamoxifen was seen in ER-positive patients [Relative risk (rr) 0.77, ci 0.63–0.93]. ER-negative patients also showed a strong trend to benefit from tamoxifen (rr 0.73, ci 0.52–1.02) which was largely confined to the PgR-positive group. Amongst the ER-positive group, PgR-positive and PgR-negative patients showed similar benefit (rr 0.81; ci 0.65–1.02 and 0.70; ci 0.49–0.99, respectively). Patients positive for HER2 did not benefit significantly (rr 1.14; ci 0.75–1.73) but this group was small.
Conclusions: Measurement of PgR status in ER-negative patients defines a group of patients that benefit from tamoxifen but would be excluded from tamoxifen therapy on the basis of ER status alone. The data are consistent with HER2 positive tumours being resistant to tamoxifen.
Key words: early breast cancer, tamoxifen, ER, PgR, EGFR, HER2
|
introduction |
|---|
|
TopAbstractintroductionmaterials and methodsresultsdiscussionReferences |
|---|
Tamoxifen is the most widely-used drug in patients with breast cancer. When used as adjuvant therapy after surgery in patients with early breast cancer it leads to enhanced disease-free and overall survival [1
] and reduces the incidence of contralateral breast cancer in this population. Although generally well-tolerated, tamoxifen is associated with a significant increase in the incidence of thrombo-embolic disease and endometrial cancer [2] but on balance the benefit from tamoxifen outweighs these negative aspects. It would, however, be advantageous to identify and exclude from tamoxifen treatment those patients who derive no significant benefit and possibly consider for them alternative endocrine therapies such as ovarian suppression or aromatase inhibitors in pre- and postmenopausal women, respectively. Aromatase inhibitors have recently been recommended for inclusion into the hormonal adjuvant treatment for steroid receptor positive patients but whether they are best used instead of or in sequence with tamoxifen and whether this choice should be influenced by other features of tumour phenotype has yet to be detemined [3]. The increasing understanding of the molecular relationships that determine the hormonal dependence of some breast carcinomas, provides the greatest potential for determining the way in which these agents may be tailored for individual therapy.
Oestrogen receptor (ER) status is widely accepted as a valuable discriminant of patient benefit from endocrine therapy. In advanced breast cancer, response to endocrine therapy is largely confined to patients with ER-positive disease [4]. ER positivity is, however, not a guarantee of sensitivity and some tumours fail to respond. There is difficulty in interpretation and comparison between studies since in most the differentiation of so-called ER-negative and positive tumours is not according to the absence/presence of ER but rather according to somewhat arbitrary cut-off levels. An additional uncertainty in the application of ER measurements for selection of patients for tamoxifen therapy has been the move from biochemical analysis of tumour homogenates to immunohistochemical analysis of tissue sections. A large, non-randomised study showed the prognostic significance of very low ER-positivity in tamoxifen-treated patients but the absence of a randomised non-treatment group did not allow a confident demonstration of treatment benefit in patients with such tumours [5]. There are few data demonstrating the reliability of the results from imunohistochemical analyses as markers of treatment benefit.
Patients with tumours expressing high levels of ER appear to derive greater benefit from tamoxifen than those with tumours having positive status but lower expression of ER [1]. It has generally been thought that expression of the progesterone receptor (PgR) gene is largely dependent on an intact ER signalling pathway [6] and as a result PgR is often used as an additional discriminant in selecting patients for hormonal therapy [7]. Over expression of the epidermal growth factor receptor (EGFR) and related HER2 (c-erbB2/neu) have both been associated with poor response to endocrine therapy [8–9]. However, the role of these as routinely measured biomarkers in the selection of patients for endocrine therapy has not been established. This study also allowed us to describe the inter-relationships between these four important markers in a relatively large population.
The benefit from tamoxifen as an adjuvant therapy has been established through the conduct of randomised-controlled trials in which a group of patients do not receive tamoxifen therapy [1]. This is also the only completely valid scenario for determining whether biomarker-identified subgroups derive differential benefit from adjuvant therapy. We have therefore assessed the potential for applying ER, PgR, EGFR and HER2 as individual and combined markers for identifying patients who benefit from tamoxifen in the context of two trials in which patients were randomised between tamoxifen and no adjuvant therapy. Importantly, the trials had very long-term, high quality follow-up data. The trials delivered 2 years of tamoxifen therapy or not and are particularly relevant to the contemporary interest in whether postmenopausal patients should be given 2–3 years of tamoxifen before receiving aromatase inhibition.
|
materials and methods |
|---|
|
TopAbstractintroductionmaterials and methodsresultsdiscussionReferences |
|---|
clinical trials
The tissues studied were archival in paraffin-embedded blocks, being surplus to pathological diagnostic requirements. They originated from patients who participated in either of two clinical trials which have been described in detail previously [10
–12]. They are described briefly:
(i) Nolvadex Adjuvant Trials Organisation (NATO).
Between November 1977 and February 1981, 1285 patients aged 
75 years were randomised to receive either 10 mg tamoxifen twice daily for 2 years or no further treatment, following total mastectomy with axillary lymph node clearance or sampling [10]. Node positive patients received regional radiotherapy. Pre-menopausal patients were only eligible for entry if they had positive axillary nodes. Five hundred and sixty four tamoxifen-treated and 567 control patients satisfied the eligibility criteria. ER analyses were performed on 525 primary tumour specimens by modification of the dextran-coated charcoal assay [11]. Median follow-up was 20 years.
(ii) CRC Adjuvant Breast Trial.
Between September 1980 and December 1985, 2230 women under 75 years of age, with stage I or II breast cancer were randomised following primary treatment into one of four treatment groups: (a) control, no further treatment, (b) tamoxifen 10 mg bid for 2 years, (c) cyclophosphamide 30 mg/kg body weight (maximum 2400 mg) i.v. for 6 days post-operatively with approximately 5 mg/kg daily in one i.v. injection or (d) tamoxifen and cyclophosphamide according to the pre-stated schedule [12]. Tissues were retrieved for analysis in the present study from patients in arms (a) and (b) only. Nine hundred and thirty seven eligible patients were randomised between these two arms. Until 1983 primary therapy was either total mastectomy with axillary lymph node sampling followed by radiotherapy for node positive disease or total mastectomy with axillary clearance and no radiotherapy. In 1983 local excision with axillary sampling and radiotherapy was allowed as an option. Median follow-up was 16 years.
For both studies the end-point examined was relapse-free survival.
tissue collection and analysis
Histopathological blocks of breast carcinomas of patients from the two clinical trials were requested from the pathology departments of centres participating in the trials. Contact was made by letter or telephone to the Head of Department and/or to the Clinical Investigator. In some cases the local histopathology department provided sections rather than the blocks. The blocks and slides were sent to the CRC Breast Cancer Trials Centre where they were assigned a code number and then forwarded to the Royal Marsden Hospital for analysis. All laboratory analyses were completed blind of patient treatment and prior to the data being returned to the Trials Centre for statistical analysis.
Sections (3 µm) were cut onto charged slides and stored and stained for biomarkers in batches. For each biomarker, positive and negative controls were developed at the start of the study to assure consistent analytical quality.
Immunohistochemical staining was conducted using the primary antibodies at stated dilutions and incubation at room temperature for stated times as follows: ER DAKO 1D5 (1/75, 2 h) [13]; PgR Novocastra 1A6 (1/40, 2 h) [14]; HER2 ICR 12 (1/800, 1 h) [15]; EGFr Menarini E30 (1/10, overnight) [16]. Antigen retrieval was used in all cases except for HER2. For the steroid receptors this involved microwaving at 750W for 10 min in pre-heated pH 6.0 0.01 M citrate buffer. For EGFR protease digestion was applied: 0.05% protease type XXV (Sigma) in phosphate buffered saline, pH 7.3 at 37°C for 15 min. The second layer for ER, PgR and EGFR was DAKO biotinylated rabbit anti-mouse immunoglobulins, 1/200 for 30 min and for HER2 was DAKO rabbit biotinylated anti-rat immunoglobulins, 1/200 for 30 min. The detection system was the DAKO StreptAvidin-Biotin Complex/horseradish peroxidase for 20 min. Comparative validation of the methods for ER and EGFR against biochemical methodology has been previously reported [13, 16].
Vimentin immunohistochemical staining was conducted on samples found to be negative for all of the 4 biomarkers. DAKO clone V9 was used at a dilution of 1/100 for 1 h following antigen retrieval for 10 min in pH 6.0, 0.01 M citrate buffer.
Scoring was conducted by one person but was reviewed as a quality control procedure by another. Instances of disagreement were resolved by examination on a 2-headed microscope. Scoring of the steroid receptors was by H-score incorporating evaluation of intensity of stain (0 to 3) and number of cells staining (range of score 0 to 300). For ER, 3 categories were defined according to the H-score: ER-negative <1, ER-poor 1–19, ER-rich 20–300. For PgR, two categories were defined: PgR-negative 0–19, PgR-positive 20–300. EGFR was scored using a modified H-score as previously described in 10 high-powered fields and positivity was defined as a score >35 as previously validated [16]. HER2 scoring involved evaluation of the entire section with any membrane staining being recorded as positive.
statistical analysis
Prior to amalgamation with the clinical databases the biological data were initially explored to examine the frequencies and distributions of the various markers. Cut-off values for the markers were predefined using previous studies. Descriptive analyses were produced from the database of each of the trials and then repeated just in those patients for whom the biological data were available. The main end-point was relapse-free survival which was defined as the time taken to the first recurrence of breast cancer (locally or as a distant metastasis), development of a new tumour or death without a previous event. To maintain consistency with the previous reporting of the trials all analyses were performed on an intention to treat basis. Relapse-free survival plots were drawn and comparisons made by the log-rank test in SPSS (version 13.0 for windows). Comparison of event rates between groups was by calculation of relative risks (rr) which were compared, i.e. tested for heterogeneity, using the methods described by EBCTCG [17]. Ninety-five percent confidence intervals (ci) were presented to illustrate the uncertainty in the estimates of the relative risks. The relative risks quoted express the event rate in the tamoxifen group relative to that in the control group, a relative risk of less than one therefore indicates there was a lower event rate in the tamoxifen group. All tests were two-tailed.
|
results |
|---|
|
TopAbstractintroductionmaterials and methodsresultsdiscussionReferences |
|---|
A total of 441 of 1131 (39%) samples were retrieved and stained from the NATO study and 413 of 937 (44%) from the tamoxifen alone and no medical treatment arms from the CRC study. Of these 30 and 11 patients, respectively, were non-evaluable, mainly because of inadequate tissue for scoring, leaving a total of 813 evaluable samples on which results were available for all four analytes.
The characteristics of the biomarker sub-group at baseline are compared with the total trial populations in Table 1. For the NATO trial 41% of the biomarker sub-group were lymph-node negative compared with 53% in the main trial. More control than tamoxifen tumours were evaluated from the CRC trial (220 versus 182, respectively, P = 0.065). Otherwise the sub-groups closely matched the respective overall trial populations.
|
Overall in the biomarkers group the tamoxifen-treated patients showed a significantly longer relapse-free survival (RFS) than the untreated controls (
2 = 10.95, P < 0.001). The relative risk of an event was 0.76 (ci 0.64–0.89) indicating a 24% reduction in risk for the tamoxifen group. There was also a significantly better RFS for the tamoxifen-treated patients in the NATO sub-group alone (rr 0.74, ci 0.59–0.91, P = 0.0076), while in the CRC trial the benefit did not quite reach statistical significance (rr 0.78, ci 0.62–1.02, P = 0.07) (Figure 1). These outcomes closely resembled those in the overall trial populations for the respective trials (data not shown).
|
The percentage positivity for the four biomarkers was: ER 76% (68% rich + 8% poor); PgR 64%; HER2 16%; EGFR 11%. A growth factor receptor (GFr) positive group was defined by positivity for EGFR or HER2 or both [18
]; because there was little overlap between the EGFR-positive and HER2-positive groups this combined group formed 24% of the total. The relationship between ER and each of the other markers is shown in Table 2a. PgR positivity was substantially higher in the ER-rich patients while EGFR and HER2 were lower; only 26 (3.2%) tumours were positive for both ER (rich + poor) and EGFR. For each of the biomarkers the level of positivity in the ER-poor group was intermediate between that in the ER-rich and ER-negative groups. In the ER-positive group, PgR positivity showed an association with growth factor receptor negativity (Table 2b) and with increased ER H-score (median[range] PgR-positive 100 [1–295]; PgR-negative 84 [1–262]; P < 0.001).
|
|
For ER the planned analysis was to compare ER-positive patients (H-score
20) with ER-negative (H-score 0) plus poor (H-score 1–19). However, it has been demonstrated since initiation of this study that tumours with very low ER levels have a better prognosis on tamoxifen than those that are immunohistochemically negative [5]. Thus ER-poor and ER-rich groups are combined to form a single ER-positive group in the analysis. Univariate analysis of prognostic factors is shown in Table 3. Treatment, tumour size, nodal status, ER and PgR status were all associated with prognosis. Age, menopausal status, study identity and HER2 and EGFR status had no relationship with prognosis.
|
The relative-risk of relapse for tamoxifen-treated patients is shown for the individual biomarkers in Table 4. The relative risk for the ER-positive group was 0.77 (0.63, 0.93) and for the ER-negative group the relative risk was 0.73 (0.52, 1.02). Thus while there was no statistically significant benefit from tamoxifen in the ER-negative group there was a strong trend to a benefit and overall there was no significant difference in the benefit from tamoxifen according to ER status. The trend to a reduced risk for the ER-negative tamoxifen-treated group was similar in both the CRC and NATO groups (data not shown).
|
Statistically significant benefit from tamoxifen was seen in each of the groups categorised as PgR-positive, PgR-negative, HER2-negative, EGFR-negative or GFr-negative. No significant benefit was seen for the EGFR-positive sub-group but the point estimate of the relative-risk was similar to those for the EGFR-negative subgroups. However, for HER2-positive tumours the relative risk was 1.14 (0.75, 1.73) and a test of heterogeneity indicated that this was significantly different from the relative risk in HER2-negative tumours (
2 = 4.32, P = 0.04). Despite this the test for heterogeneity for the interaction between treatment and GFr was not significant (2 = 1.79, P = 0.18). In patients who were ER-positive, PgR status had little effect on benefit from tamoxifen (PgR-positive rr 0.81, ci 0.65–1.02; PgR-negative rr 0.70, ci 0.49–0.99) (Figure 2). It is interesting to note that this is the case despite the different proportions of growth factor receptor positivity and concentrations of ER in the ER-positive population according to PgR status (Table 2b).
|
In the ER-negative group differences in outcome according to PgR status were apparent: while the PgR-negative group derived no clear benefit (rr 0.79 ci 0.55–1.14, P = 0.21), the PgR-positive group showed a suggestion of a reduction in risk of relapse (rr 0.46, ci 0.11–1.19, P = 0.11). These two sub-groups made up 21% and 3.2% of the total population, respectively.
The combined analysis of ER and PgR were therefore taken to define steroid receptor-positive (ER and/or PgR-positive). This group showed clear benefit from tamoxifen (rr 0.75 ci 0.62–0.90). Analyses of the impact of growth factor receptors on relapse free survival were conducted in the steroid receptor-positive group. There were 75 (9.3%) patients that were both steroid receptor-positive and HER2-positive, and there was no significant benefit in this group (Table 5, Figure 3). Only 26 (3.2%) patients were EGFR positive and steroid receptor-positive but in contrast to the HER2-positive group this small subgroup appeared to derive benefit from tamoxifen. There was an overlap between these two growth factor receptor-positive subgroups of only three patients such that the combined GFr-positive group that were also steroid receptor-positive comprised 98 patients but this did not define a group that lacked benefit from tamoxifen.
|
|
ER status had previously been measured by ligand-binding assay (dextran-coated charcoal assay) in 525 (46%) of the 1131 tumours of the NATO study shortly after excision [9
]. Of the 525, 202 were included in this biomarker study and therefore also have ER values by immunocytochemistry. A cut-off of 5 fmol/mg protein in the original data set indicated 68% ER positivity in the 202 samples, which is identical to the proportion of ER-rich tumours by immunohistochemistry in the total population. Comparison of these ER-rich values with the ligand binding assay values showed 160 of 202 (79%) concordance with similar numbers (22 and 20) in the two discordant groups. Factors which were significant on univariate analysis were considered for inclusion in a multivariate analysis using Cox Regression. ER was only considered as a dichotomous variable (negative versus poor + rich) and both tumour size and nodal status were fitted as continuous three level factors. Multivariate analysis did not provide any clear indication of subgroups of patients that benefited or received no benefit from tamoxifen. Two contrasting but equally likely explanations existed. These were that tamoxifen was effective in all patients or that tamoxifen was only effective in patients who are HER2 negative (–2*Log(likelihood)'s for the two models were 6251.5 and 6251.6, respectively). These results reflect the fact that no difference in the tamoxifen effect was seen in ER positive and ER negative patients and that for HER2-positive tumours the relative risk was significantly higher than the relative risk in HER2-negative tumours. However, it was not possible to distinguish between these two explanations on the basis of the data from this study.
|
discussion |
|---|
|
TopAbstractintroductionmaterials and methodsresultsdiscussionReferences |
|---|
The two trials chosen for this study had the advantage that in each tamoxifen was randomised against no medical treatment and therefore should not have been subject to the confounding effects of concomitant chemotherapy, e.g. endocrine effects in premenopausal women by virtue of an ovarian ablative effect of chemotherapy [19
]. Approximately 40% of tumours were available. The relative risk for relapse free survival was 0.76. This is identical to the effect reported in the Overview analysis of 1995 for all trials of about 2-years treatment duration [1] and therefore may be considered representative of this clinical setting. The duration of tamoxifen in current clinical practise is now usually 5 years. However, while the overall benefit from tamoxifen is greater after 5 years the proportional effects of the biomarkers assessed here is likely to be similar at 2 and 5 years. Additionally, there is a contemporary debate as to whether 2 years of tamoxifen treatment prior to switching to an aromatase inhibitor may be preferable to initiating adjuvant treatment with the aromatase inhibitor [20]: the current data from trials of 2 years of tamoxifen are particularly relevant to the issue of switching. The blocks were between 10 and 23 years old at the time of analysis. It was considered impractical to attempt to assess the nature of protocols for tissue fixation and processing which may conceivably have affected the levels of positivity of the biomarkers. Instead, three approaches were taken to assess the validity of the data prior to comparative statistical analysis. Where there were large centres contributing more than 40 samples the descriptive data were reviewed for any apparently aberrant sets of data; none were noted. In the 60 samples (7.3%) which were negative for all four markers, vimentin staining was conducted to assess the possible degradation of antigens; in all cases staining for vimentin was positive. Whilst this was reassuring it did not exclude the possibility of specific epitope degradation. Therefore the data were also appraised for expected levels of biomarker positivity and for expected relationships between the markers.
Some degree of ER positivity was recorded in 76% of tumours, which is within the range of values previously reported. For example, McGuire reported in 1980 (central to the times of recruitment for this study) that 73% of a large series of primary breast carcinomas were ER-positive (3 fmol/mg protein) [4]. More recently somewhat higher percentages of ER positivity have been described (e.g. 79%; reference 5) but this may, at least in part, reflect the earlier detection of breast carcinomas in modern practice. McGuire also reported 58% PgR positivity which is also similar to the 64% reported here [14].
As expected there was a strong positive correlation between ER and PgR positivity, and strong negative correlation between ER and EGFr, with a rather weaker negative correlation between ER and Her2. Each of these relationships has been previously reported [9, 12]. For each marker the ER-poor group showed a proportion of positive tumours intermediate between those in the ER-negative and -positive groups. It was particularly notable, given the data presented here on tamoxifen benefit in ER negative tumours, that 4.6% of tumours were ER-negative/PgR-positive; 8.9% were ER-negative/poor/PgR-positive. McGuire [4] reported ER-negative/PgR positive tumours as making up 3% of postmenopausal and 9% of premenopausal women.
The 16% positivity rate for Her2 falls within the very wide range reported for this membrane receptor using a variety of antibodies [22]. Our recent (unpublished) data indicates that positivity recorded with the ICR12 antibody closely corresponds to the 3+ category (but not the 2+ category) with the American HPB-approved DAKO Herceptest. The positivity rate for EGFr of 11% is about half that in our validation series [16]. However, it should be noted that 40% of the tumours in that series were ER-negative compared with 24% in the current report, and as noted above it is widely recognised that EGFr is expressed almost exclusively in ER-negative tumours [21]. Each of these sets of biomarker data support the validity of the current study.
The data also indicate that amongst ER+ tumours a significantly greater number of PgR-negative than PgR-positive tumours express HER2 and/or EGFR (approximately 30% versus 10%). This is consistent with other recent reports [23, 24].
Overview analysis has revealed a significant advantage for patients receiving adjuvant tamoxifen for both recurrence and overall mortality [1]. In the most recent overview [25], for patients receiving treatment for 5 years the mean risk reduction for relapse was 31% ± 3 (SD) and for mortality due to breast cancer it was 24% ± 4 (SD). The overview also showed a significant risk reduction for relapse in the ER-poor group for 1–2 years tamoxifen 11% ± 4 (54 000 patients) but this was not significant for 5 years tamoxifen 4% ± 7 (28 000 patients). When the 1–2 years tamoxifen ER-poor group was subcategorised according to PgR, those with PgR-poor status were seen to gain no benefit from tamoxifen but the PgR-positive and PgR-unknown groups had risk reductions for relapse with relative risks of 14% ± 12 and 15% ± 5, respectively, the latter was highly significant. The corresponding figures for 5 years tamoxifen were 8% ± 15 and 21% ± 15 respectively.
The data reported here do not show a clear separation of benefit from tamoxifen according to ER status, with there being closely similar point estimates of relative risk for the ER-positive and ER-negative groups (irrespective of the allocation of the ER-poor group). The combination of ER with PgR data indicates that the ER-negative PgR-positive group of patients may gain substantial benefit from tamoxifen, the point estimate indicating a 54% risk reduction for this subgroup (P = 0.11). In contrast the point estimate for the ER-negative/PgR-negative group was for a 21% risk reduction (P = 0.21). A non-significant increase in risk of 13% (P = 0.34) was observed in the recently published GABG-IV trial [41] (829 patients), which assessed the value of tamoxifen (30 mg) versus no additional treatment following chemotherapy in postmenopausal patients with hormone receptor negative disease. It has been known for many years that patients with ER-negative/PgR-positive tumours show a good response to hormonal therapy in metastatic disease [4, 26] and it is common practise for positivity of either one of these two receptors to be sufficient for inclusion of a patient in clinical trials of new hormonal therapy. However, the application of PgR analyses in the UK is not universal. Conduct of PgR analyses in patients already known to be ER-positive does not seem necessary since this does not define a non-responsive group, but PgR analysis in ER-negative patients could identify a group (about 3% of the total breast cancer population) who would gain substantial benefit from tamoxifen therapy. Our data are consistent with the 2005 International Consensus Guidelines (St Gallen 2005) [42] which were the first consensus guidelines to advocate endocrine responsiveness as the major criterion for choice of endocrine treatment.
The existence of an ER-negative/PgR-positive group has been universally observed but given the oestrogen dependence of PgR it is biologically unexpected and remains mechanistically unexplained. It has been suggested that a constitutively active ER variant which lacks the ligand-binding domain might explain this [26] but the biological importance of this has not been substantiated [27]. It is possible that the apparent benefit of tamoxifen in ER-negative/PgR-positive tumours relates to its having biochemical effects independent of ER. These include inhibition of calmodulin-mediated processes [28] and protein-kinase C activity [29]. Additionally tamoxifen has been shown to reduce plasma levels of the breast tissue mitogen IGF-1 [30] and to enhance breast tumour levels of TGF
[31] which may have endocrine and paracrine effects on malignant breast cells, respectively. Lastly, it is also possible that ER-negative/PgR-positive tumours exist as a result of false negativity of ER and that this explains the benefit from tamoxifen in that group. This could also explain why the overview analysis found benefit in this subgroup in the 1–2 year but not 5 year studies given that these shorter term studies were generally the earlier to be conducted and involved ER assays in their infancy.
The presence of PgR in the ER-positive group of patients did not significantly affect the benefit seen with tamoxifen. This is similar to the data from the overview analysis [1, 25]. They disagree with the data from Bardou et al. [32] but that study did not have a randomized non-treatment control arm. While the present study would indicate no value for the measurement of PgR in ER-positive patients a recent retrospective sub-group analysis from the ATAC trail suggests that the aromatase inhibitor anastrozole may be substantially more effective than tamoxifen in ER-positive/PgR-negative tumours [33].
The relatively low-level of expression of EGFr in this study and its strong negative correlation with ER expression leads to it having no perceptible role in selection of non-responsive patients. However, the data presented here and elsewhere [18, 34–40] indicate that a role may develop for the measurement HER2 to assess hormone responsiveness. Overall HER2 positive patients failed to benefit from tamoxifen treatment in this study. This is consistent with several reports which suggest that HER2-positive tumours do not benefit from tamoxifen [18, 34–40]. One study reported that there was a detrimental effect of adjuvant tamoxifen in HER2 positive patients [35]. The present study supports the lack of benefit from tamoxifen but like other studies there are an insufficient number of HER2-positive/ER-positive patients for there to be confidence in the individual data sets in this group. The lack of concordance between different immunohistochemical techniques for HER2 [22] leads to further uncertainty in this issue. While the present data make the evidence more compelling for tamoxifen resistance, an overview analysis of comparable trials would be helpful, preferably assessing Her2 amplification status which has greater reproducibility between laboratories than immunohistochemistry. Data that indicate a greater benefit of aromatase inhibitors than tamoxifen in HER2+ patients in the neoadjuvant setting [41, 42] indicate that these may be preferred agents for the treatment of such patients.
In summary, this retrospective blinded study of 2 years tamoxifen adjuvant therapy suggests that ER analysis alone is insufficient to select patients for treatment, and that PgR analysis should be conducted in ER-negative patients to ensure that potential responders are not denied treatment. PgR status does not appear to be helpful in identifying ER-positive patients that gain differential benefit from tamoxifen. The data support earlier studies for HER2 having a role in identifying patients with a low likelihood of benefiting from tamoxifen.
|
Acknowledgements |
|---|
Prof. B. Gusterson, Prof. R. Nicholson, Dr. J. Cuzick, Prof. J. Sloane, Mr. A. J. Wilson, Mr. J. Latteier were also members of the CRC BCTG Biomarkers Working Party that helped in guiding this study.
The work was supported by the NHS National Cancer R & D Programme. We are indebted to the many clinical trialists and particularly their associated pathologists for contributing to their cases to this study.
Received for publication November 2, 2005. Revision received January 13, 2006. Accepted for publication January 16, 2006.
|
References |
|---|
|
TopAbstractintroductionmaterials and methodsresultsdiscussionReferences |
|---|
1. Early Breast Cancer Trialists' Collaborative Group. Tamoxifen for early breast cancer: an overview of the randomised trials. Lancet 1998; 351: 1451–1467.[CrossRef][Web of Science][Medline]
2. Fisher B, Constantino JP, Wickerham DL et al. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1. J Natl Cancer Inst 1998; 90: 1371–1388.
3. Winer EP, Hudis C, Burstein HJ et al. American Society of Clinical Oncology technology assessment on the use of aromatase inhibitors as adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer: status report 2004. J Clin Oncol 2005; 23: 619–629.
4. McGuire WL. Steroid hormone receptors in breast cancer treatment strategy. Recent Prog Hormone Res 1980; 36: 135–156.[Medline]
5. Harvey JM, Clark GM, Osborne CK, Allred DC. Estrogen receptor status by immunohistochemistry is superior to the ligand-binding assay for predicting response to adjuvant endocrine therapy in breast cancer. J Clin Oncol 1999; 17: 1471–1481.
6. Horwitz KB, McGuire WL. Oestrogen control of progesterone receptor in human breast cancer: correlation with nuclear processing of oestrogen receptor. J Biol Chem 1978; 253: 2223–2228.
7. Alexieva-Figusch J, Van Putten WLJ, Blankenstein MA et al. The prognostic value and relationships of patient characteristics, estrogen and progestin receptors and site of relapse in primary breast cancer. Cancer 1988; 61: 758–768.[CrossRef][Web of Science][Medline]
8. Harris AL, Nicholson S, Sainsbury JRC et al. Epidermal growth factor receptors in breast cancer: association with early relapse and death, poor response to hormones and interaction with neu. J Steroid Biochem 1989; 34: 123–133.[CrossRef][Web of Science][Medline]
9. Wright C, Nicholson S, Angus B et al. Relationship between erb-B2 protein product expression and response to endocrine therapy in advanced breast cancer. Br J Cancer 1992; 65: 118–121.[Web of Science][Medline]
10. Nolvadex Adjuvant Trial Organization. Controlled trial of tamoxifen as single adjuvant agent in management of early breast cancer. Lancet 1985; i: 836–839.
11. Nolvadex Adjuvant Trial Organisation. Controlled trial of tamoxifen as single adjuvant agent in management of early breast cancer. Analysis at Eight Years. Brit J Cancer 1988; 57: 608–611.[Web of Science][Medline]
12. CRC Adjuvant Breast Trial Working Party. Cyclophosphamide and tamoxifen as adjuvant therapies in the management of breast cancer. Br J Cancer 1988; 57: 604–607.[Web of Science][Medline]
13. Saccani-Jotti G, Johnston SRD, Salter J et al. Comparison of a new immunohistochemical assay for oestrogen receptor in paraffin wax embedded breast carcinomas tissue with quantitative enzyme immunoassay. J Clin Path 1994; 47: 900–905.
14. Detre S, Salter J, Barnes DM et al. Time-related effects of oestrogen withdrawal on proliferation and cell death-related events in MCF7 xenografts. Int J Cancer 1999; 81: 309–313.[CrossRef][Medline]
15. Styles JM, Harrison S, Gusterson BA, Dean CJ. Rat monoclonal antibodies to the external domain of the product of the c-erbB2 proto-oncogene. Int J Cancer 1990; 45: 320–324.[Web of Science][Medline]
16. Newby JC, A'Herne RA, Leek RD et al. Immunohistochemical assay for epidermal growth factor receptor on paraffin-embedded sections: validation against ligand binding assay and clinical relevance in breast cancer. Brit J Cancer 1995; 71: 1237–1242.[Web of Science][Medline]
17. Early Breast Cancer Trialist's Group. Statistical Methods. In: Treatment of Early Breast Cancer. Volume 1. Worldwide Evidence 1985–1990. Oxford University Press, Oxford 1990; 12–18.
18. Newby JC, Johnston SRD, Smith IE et al. Expression of epidermal growth factor receptor and c-erbB2 during the development of tamoxifen resistance in human breast cancer. Clin Cancer Res 1997; 3: 1643–1651.[Abstract]
19. Dowsett M, Richner J. Effects of cytotoxic chemotherapy on ovarian and adrenal steoridogenesis in premenopausal breast cancer patients. Oncology 1991; 48: 215–220.[CrossRef][Web of Science][Medline]
20. Howell A. Adjuvant aromatase inhibitors for breast cancer. Lancet 2005; 366: 431–433.[Medline]
21. Sainsbury JRC, Farndon JR, Sherbet GV et al. Epidermal-growth-factor receptors and oestrogen receptors in human breast cancer. Lancet 1985; i: 364–366.
22. Press MF, Hung G, Godolphin W, Slamon DJ et al. Sensitivity of HER-2/neu antibodies in archival tissue samples: potential source of error in immunohistochemical studies of oncogene expression. Cancer Res 1994; 54: 2771–2777.
23. Tovey S, Dunne B, Witton CJ et al. Can molecular markers predict when to implement treatment with aromatase inhibitors in invasive breast cancer? Clin Cancer Res. 2005; 11: 4835–4842.
24. Arpino G, Weiss H, Lee A et al. Estrogen receptor positive (ER+), progesterone receptor (PgR-) breast cancer: new insights into molecular mechanisms and clinical implications. Breast Cancer Res Treat 2004; 88: S21.
25. Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials. Lancet. 2005; 365: 1687–1717.[CrossRef][Web of Science][Medline]
26. McGuire WL, Chamness GC, Fuqua SAW. Estrogen receptor variants in clinical breast cancer. Endocrinol 1991; 5; 1571–1577.
27. Daffada AAI, Johnston SRD, Smith IE et al. Exon 5-deletion variant oestrogen receptor mRNA expression in relation to tamoxifen resistance and PgR/pS2 status in human breast cancer. Cancer Res 1995; 55: 288–293.
28. Rowlands MG, Parr IB, McGague R et al. Variation of inhibition of calmodulin dependent cyclic AMP phosphodiesterase amongst analogues of tamoxifen; correlations with cytoxicity. Biochem Pharmacol 1990; 49: 283–289.
29. Bignon E, Ogita K, Kishimoto A, et al. Modes of inhibition by protein kinase C by triphenylacrylonitrile antiestrogens. Biochem Biophys Res Commun 1989; 163: 1377–1383.[CrossRef][Web of Science][Medline]
30. Ho GH, Ji CY, Phang BH et al. Tamoxifen alters levels of insulin-like growth factors and binding proteins in postmenopausal breast cancer patients: a prospective paired short study. Ann Surg Oncol 1998; 5: 361–367.[Abstract]
31. Butta A, MacLennan K, Flanders K et al. Evidence for the induction of transforming growth factor ß1 in human breast cancer in vivo following tamoxifen treatment. Cancer Res 1992; 52: 4261–4264.
32. Bardou VJ, Arpino G, Elledge RM et al. Progesterone receptor status significantly improves outcome prediction over estrogen receptor status alone for adjuvant endocrine therapy in two large breast cancer databases. J Clin Oncol. 2003; 21: 1973–1979.
33. Dowsett M, Cuzick J, Wale C et al. Retrospective analysis of time to recurrence in the ATAC trail according to hormone receptor status: an hypothesis generating study. J Clin Oncol 2005; 23: 7512–7517.
34. Berns EMJJ, Foekens JA, van Staveren IL et al. Oncogene amplification and prognosis in breast cancer: relationship with systematic treatment. Gene 1995; 159: 11–18.[CrossRef][Web of Science][Medline]
35. Bianco AR, De Laurentis M, Carlomagno C et al. 20 year update of the Naples GUN trial of adjuvant breast cancer therapy: evidence of interaction between c-erbB2 expression and tamoxifen efficacy. Proc Am Soc Clin Oncol 1998; 17: 97A.
36. Leitzel K, Teramoto Y, Konrad K et al. Elevated serum c-erbB2 antigen levels and decreased response to hormone therapy of breast cancer. J Clin Oncol 1995; 13: 1129–1135.[Abstract]
37. Nicholson RI, McClelland RA, Finlay P et al. Relationship between EGF-R, c-erbB2 protein expression and Ki67 immunostaining in breast cancer and hormone sensitivity. Eur J Cancer 1993; 29A: 1018–1023.
38. Plunkett TA, Houston SJ, Rubens RD et al. C-erbB2 is a marker of resistance to endocrine therapy in advanced breast cancer. Proc Am Soc Clin Oncol 1998; 17: 103a.
39. Wright C, Nicholson S, Angus B et al. Relationship between c-erbB2 protein product expression and response to endocrine therapy in advanced breast cancer. Br J Cancer 1992; 65: 118–121.
40. Yamauchi H, O'Neill A, Gelman R et al. Prediction of response to antiestrogen therapy in advanced breast cancer patients by re-treatment circulating levels of extracellular domain of the HER-2/c-neu protein. J Clin Oncol 1997; 15: 2518–2525.
41. Kaufman M, Graf E, Jonat W et al. Tamoxifen versus control after adjuvant, risk-adapted chemotherapy in postmenopausal, receptor-negative patients with breast cancer (GABG-IV D-93) – The German Adjuvant Breast Group. J Clin Oncol 2005; 23: 7842–7848.
42. Goldhirsch A, Glick JH, Gelber RD et al. Meeting highlights: International expert consensus on the primary therapy of early breast cancer 2005. Ann Oncol 2005; 16: 1669–1583.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. Merglen, H. M. Verkooijen, G. Fioretta, I. Neyroud-Caspar, V. Vinh-Hung, G. Vlastos, P. O. Chappuis, M. Castiglione, E. Rapiti, and C. Bouchardy Hormonal therapy for oestrogen receptor-negative breast cancer is associated with higher disease-specific mortality Ann. Onc., May 1, 2009; 20(5): 857 - 861. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. S. Ross, E. A. Slodkowska, W. F. Symmans, L. Pusztai, P. M. Ravdin, and G. N. Hortobagyi The HER-2 Receptor and Breast Cancer: Ten Years of Targeted Anti-HER-2 Therapy and Personalized Medicine Oncologist, April 1, 2009; 14(4): 320 - 368. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S Badve and H Nakshatri Oestrogen-receptor-positive breast cancer: towards bridging histopathological and molecular classifications J. Clin. Pathol., January 1, 2009; 62(1): 6 - 12. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Dowsett and A. K. Dunbier Emerging Biomarkers and New Understanding of Traditional Markers in Personalized Therapy for Breast Cancer Clin. Cancer Res., December 15, 2008; 14(24): 8019 - 8026. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Bicaku, D. C. Marchion, M. L. Schmitt, and P. N. Munster Selective Inhibition of Histone Deacetylase 2 Silences Progesterone Receptor-Mediated Signaling Cancer Res., March 1, 2008; 68(5): 1513 - 1519. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Dowsett, C. Allred, J. Knox, E. Quinn, J. Salter, C. Wale, J. Cuzick, J. Houghton, N. Williams, E. Mallon, et al. Relationship Between Quantitative Estrogen and Progesterone Receptor Expression and Human Epidermal Growth Factor Receptor 2 (HER-2) Status With Recurrence in the Arimidex, Tamoxifen, Alone or in Combination Trial J. Clin. Oncol., March 1, 2008; 26(7): 1059 - 1065. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Colleoni, G. Viale, D. Zahrieh, L. Bottiglieri, R. D. Gelber, P. Veronesi, A. Balduzzi, R. Torrisi, A. Luini, M. Intra, et al. Expression of ER, PgR, HER1, HER2, and response: a study of preoperative chemotherapy Ann. Onc., March 1, 2008; 19(3): 465 - 472. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. I. Pritchard, H. Messersmith, L. Elavathil, M. Trudeau, F. O'Malley, and B. Dhesy-Thind HER-2 and Topoisomerase II As Predictors of Response to Chemotherapy J. Clin. Oncol., February 10, 2008; 26(5): 736 - 744. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. K.T. Tan, L. K. Tan, K. Yu, P. H. Tan, M. Lee, L. H. Sii, C. Y. Wong, G. H. Ho, A. W.Y. Yeo, P. K.H. Chow, et al. Clinical Validation of a Customized Multiple Signature Microarray for Breast Cancer Clin. Cancer Res., January 15, 2008; 14(2): 461 - 469. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Rakha and I. O. Ellis In Reply J. Clin. Oncol., January 10, 2008; 26(2): 336 - 338. [Full Text] [PDF]
|
|
|
|
 |
|
 M. Dowsett Factors Predicting Response and Resistance to Endocrine Therapy of Breast Cancer ASCO Educational Book, January 1, 2008; 2008(1): 14 - 17. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Rakha, M. E. El-Sayed, A. R. Green, E. C. Paish, D. G. Powe, J. Gee, R. I. Nicholson, A. H.S. Lee, J. F.R. Robertson, and I. O. Ellis Biologic and Clinical Characteristics of Breast Cancer With Single Hormone Receptor Positive Phenotype J. Clin. Oncol., October 20, 2007; 25(30): 4772 - 4778. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Guler, D. Iliopoulos, N. Guler, C. Himmetoglu, M. Hayran, and K. Huebner Wwox and Ap2{gamma} Expression Levels Predict Tamoxifen Response Clin. Cancer Res., October 15, 2007; 13(20): 6115 - 6121. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Pruthi, K. R. Brandt, A. C. Degnim, M. P. Goetz, E. A. Perez, C. A. Reynolds, P. J. Schomberg, G. K. Dy, and J. N. Ingle A Multidisciplinary Approach to the Management of Breast Cancer, Part 1: Prevention and Diagnosis Mayo Clin. Proc., August 1, 2007; 82(8): 999 - 1012. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Giltnane, L. Ryden, M. Cregger, P.-O. Bendahl, K. Jirstrom, and D. L. Rimm Quantitative Measurement of Epidermal Growth Factor Receptor Is a Negative Predictive Factor for Tamoxifen Response in Hormone Receptor Positive Premenopausal Breast Cancer J. Clin. Oncol., July 20, 2007; 25(21): 3007 - 3014. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L Mauriac, A Keshaviah, M Debled, H Mouridsen, J. Forbes, B Thurlimann, R Paridaens, A Monnier, I Lang, A Wardley, et al. Predictors of early relapse in postmenopausal women with hormone receptor-positive breast cancer in the BIG 1-98 trial Ann. Onc., May 1, 2007; 18(5): 859 - 867. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Kennecke, I. Olivotto, C Speers, B Norris, S. Chia, C Bryce, and K. Gelmon Late risk of relapse and mortality among postmenopausal women with estrogen responsive early breast cancer after 5 years of tamoxifen Ann. Onc., January 1, 2007; 18(1): 45 - 51. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Dowsett Estrogen Receptor: Methodology Matters J. Clin. Oncol., December 20, 2006; 24(36): 5626 - 5628. [Full Text] [PDF]
|
|
|
|
|
|
R Ponzone, F Montemurro, F Maggiorotto, C Robba, D Gregori, M. Jacomuzzi, F Kubatzki, D Marenco, A Dominguez, N Biglia, et al. Clinical outcome of adjuvant endocrine treatment according to PR and HER-2 status in early breast cancer Ann. Onc., November 1, 2006; 17(11): 1631 - 1636. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||