Evaluating the effect of tobacco on prostate cancer outcomes with VEGF-targeted therapy.

129 Background: Docetaxel/prednisone (DP) plus bevacizumab (B) demonstrated a superior progression-free survival (PFS) but did not prolong overall survival (OS) in comparison to DP monotherapy in CALGB 90401, a study of 1,050 patients with metastatic castration-resistant prostate cancer (CRPC) who had not received prior chemotherapy for metastatic disease. Tobacco use increases VEGF levels, suggesting the benefit of bevacizumab may be greater in patients who use tobacco. METHODS: The association of tobacco usage and OS was evaluated. Patient-reported history of tobacco usage was prospectively collected for patients on CALGB 90401. Within each smoking status group, the log-rank test was used to compare the survival time between the two treatment arms. The proportional hazards model was used to test for smoking by treatment interaction predicting OS. RESULTS: Of 865 patients with available smoking history, 21%, 30% and 49% were current, former, and never smokers. As summarized in the table below, there was a non-statistically significant improvement in OS for current smokers treated on the DP+B arm compared to the DP arm. However, treatment-by-smoking interaction was not statistically significant in predicting OS (p=0.299). CONCLUSIONS: There was a trend toward an improvement in OS for current smokers treated with DP+B. The accuracy of patient-reported smoking status will be confirmed with serum cotinine levels in a pilot study. The effect of tobacco use on cancer outcomes with VEGF targeted therapy will be evaluated in other malignancies.

Duke Scholars

Author Susan Halabi Biostatistics & Bioinformatics, Division of Biostatistics