Annals of Oncology Advance Access published online on November 4, 2009
Annals of Oncology, doi:10.1093/annonc/mdp466
Optimizing the size variation threshold for the CT evaluation of response in metastatic renal cell carcinoma treated with sunitinib
1 Department of Radiology, Georges Pompidou European Hospital, Assistance Publique Hôpitaux de Paris, Paris Descartes University
2 INSERM U970-laboratoire de Recherche en Imagerie team 2, Assistance Publique Hôpitaux de Paris, Paris Descartes University
3 Epidemiology and Clinical Research Unit, INSERM Centre d'Investigation Epidémiologique 4
4 Department of Oncology, Georges Pompidou European Hospital, Assistance Publique Hôpitaux de Paris, Paris Descartes University, Paris; Departments of
5 Medical Oncology
6 Radiology, Gustave Roussy Institute, Villejuif
7 Biological Immunology Unit, Georges Pompidou European Hospital, Ecole Nationale vétérinaire d'Alfort EA 4054, Assistance Publique Hôpitaux de Paris, Paris Descartes University, Paris, France
* Correspondence to: Pr C. A. Cuenod, 20–40 rue Leblanc, 75015 Paris, France. Tel: +33-1-56-09-38-41; Fax: +33-1-56-09-38-50; E-mail: ca{at}cuenod.net
Background: In metastatic renal cell carcinoma (mRCC), antiangiogenic treatments rarely achieve a reduction of –30% in the sum of longest diameters (SLD) of target lesions required by RECIST for an ‘objective response’, although they objectively improve progression-free survival (PFS). We sought to determine a threshold for the computed tomography evaluation of these patients’ best reflecting patient outcome.
Patients and methods: In 334 mRCC patients treated with sunitinib, we tested thresholds from –45% to +10%. We classified patients as ‘responders’ when the best relative variation of the sum of longest diameters (
SLD) reached the tested threshold and as ‘nonresponders’ otherwise. For each tested threshold, the median PFS of the two groups were compared. Receiver operating characteristic (ROC) analysis was also carried out among the 103 patients that progressed during follow-up. Finally, the ‘optimal’ threshold was retested on an independent cohort of 39 patients.
Results: The SLD threshold of –10% gave the most significant difference. It divided patients into 256 responders and 78 nonresponders (median PFS 11.1 and 5.6 months). The same –10% threshold was found using the ROC analysis. Results were confirmed on the external validation cohort.
Conclusion: A variation of –10% in the SLD accurately and rapidly identifies mRCC patients benefiting from sunitinib.
antiangiogenic, computed tomography, kidney cancer, metastatic renal cell carcinoma, progression-free survival, RECIST
Received for publication May 15, 2009. Revision received July 31, 2009. Accepted for publication August 24, 2009.