Yohan Loriot

Objective: To evaluate the benefit of docetaxel rechallenge in patients with metastatic castration‐resistant prostate cancer ( mCRPC ) relapsing after an initial good response to first‐line docetaxel. Patients and Methods: We retrospectively reviewed the records of consecutive patients with mCRPC with a good response to first‐line docetaxel [serum prostate specific antigen ( PSA ) decrease ≥50%; no clinical/radiological progression]. We analysed the impact of management at relapse (docetaxel rechallenge or non‐taxane‐based therapy) on PSA response, symptomatic response (performance status/pain/analgesic consumption), and overall survival ( OS ). We used multivariate stepwise logistic regression to analyse potential predictors of a favourable outcome. Results: We identified 270 good responders to first‐line docetaxel. The median progression‐free interval ( PFI ) was 6 months from the last docetaxel dose. At relapse, 223 patients were rechallenged with docetaxel (82.5%) and 47 received non‐taxane‐based therapy. There was no significant difference in median OS {18.2 [95% confidence interval ( CI ) 16.1–22.00] and 16.8 [95% CI 13.4–21.5] months, respectively, P = 0.35}. However, good PSA response and symptom relief/stable disease were more frequent on docetaxel rechallenge (40.4% vs 10.6%, P < 0.001 for PSA ). A PFI of >6 months and added estramustine predicted a good PSA response and symptomatic response on docetaxel rechallenge but only a PFI of >6 months predicted longer OS . Haemoglobin (6 months, but did not prolong survival. Potential benefits should be weighed against the risk of cumulative toxicity.