Prognostic value of Caveolin-1 in patients treated with radical prostatectomy: a multicentric validation study

Objective: To validate Caveolin-1 as an independent prognostic marker of biochemical recurrence (BCR) in a large multi-institutional cohort of patients with prostate cancer treated with radical prostatectomy (RP). Patients and Methods: Caveolin-1 expression was evaluated by immunochemistry on a tissue microarray in 3 117 patients treated with RP for prostate cancer at five institutions. Univariable and multivariable Cox proportional hazards regression models assessed the association of Caveolin-1 status with BCR. Harrell's c-index quantified prognostic accuracy. Results: Caveolin-1 was overexpressed in 644 (20.6%) patients and was associated with higher pathological Gleason sum (P = 0.002) and lymph node metastases (P = 0.05). Within a median (interquartile range) follow-up of 38 (21–66) months, 617 (19.8%) patients experienced BCR. Patients with overexpression of Caveolin-1 had worse BCR-free survival than those with normal expression (log-rank test, P = 0.004). Caveolin-1 was an independent predictor of BCR in multivariable analyses that adjusted for the effects of standard clinicopathological features (hazard ratio 1.21, P = 0.037). Addition of Caveolin-1 in a model for prediction of BCR based on these standard prognosticators did not significantly improve the predictive accuracy of the model. In subgroup analyses, Caveolin-1 was associated with BCR in patients with favourable pathological features (pT2pN0 and Gleason score = 6; P = 0.021). Conclusions: We confirmed that overexpression of Caveolin-1 is associated with adverse pathological features in prostate cancer and independently predicts BCR after RP, especially in patients with favourable pathological features. However, it did not add prognostically relevant information to established predictors of BCR, limiting its use in clinical practice.