Boston-Obesity is independently related to better outcomes in patients with metatstatic renal cell carcinoma who are treated with vascular endothelial growth factor (VEGF), results from a multicenter study indicate.
In the retrospective study, overall survival in patients treated with VEGF-targeted therapy for metastatic RCC was greater as body mass index (BMI) and body surface area (BSA) increased. The study data were presented at the 2010 American Society of Clinical Oncology annual meeting in Chicago.
On univariate analysis, median overall survival was 32.5 months in the obese patients compared to 20.6 months in the normal/overweight cohort (p=.001). On multivariate analysis (adjusted for known adverse prognostic factors), obese patients had a better overall survival compared to normal/overweight patients, with a hazard ratio of 0.67 (p=.01).
Compared to the obese group, the normal BMI/low BSA group had an adjusted time to treatment failure (13 months vs. 5 months) that was 54% worse and an adjusted overall survival (33 months vs. 15 months) that was 53% worse.
"Our next step is to externally validate our results and find a hypothesis for these counterintuitive findings," Dr. Choueiri said. "Is it because patients with lower BMI/lower BSA get more toxicity and have less time on therapy that translates into a worse survival, is it because they are declining rapidly, or is it a difference in drug levels that accumulate or not in fat?"
Several of the study's authors disclosed a financial and/or other relationship with Pfizer, Bayer, Genentech, GlaxoSmithKline, Novartis, Onyx Pharmaceuticals, and Roche.