Survival of patients with small cell carcinoma of the prostate during 1973-2003: a population-based study.

OBJECTIVE: To describe the survival of patients with primary small cell carcinoma (SCC) of the prostate and assess prognostic factors based on a large population sample.

PATIENTS AND METHODS: A total of 241 cases of SCC of the prostate were reported to the Surveillance, Epidemiology, and End Results (SEER) registries from 1973 to 2003 of which 191 cases were included in our study. We used the Kaplan-Meier method for estimating survival, and Cox proportional hazard regression modelling to evaluate prognostic variables.

RESULTS: The overall age-adjusted incidence rate was 0.278 per 1,000,000 (95% confidence interval, 0.239-0.323). In all, 60.5% presented as metastatic disease compared with 39.5% who presented as local/regional disease (P= 0.012). The 12, 24, 36, 48 and 60 months observed survival rates were 47.9%, 27.5%, 19%, 17% and 14.3% respectively. On univariate analyses, age <60, concomitant low-grade prostatic adenocarcinoma, absence of metastasis, prostatectomy and radiation therapy were favourable prognostic factors. In multivariate regression modelling, age, pathology and stage were strong predictors of survival.

CONCLUSIONS: Using the SEER database, we present the largest study describing the epidemiology of primary SCC of the prostate. We found age, concomitant low-grade prostatic adenocarcinoma, and stage of the disease to be the strongest predictors of survival for patients with prostatic SCC. Future studies evaluating a broader range of clinical and molecular markers are needed to refine the prognostic model of this relatively rare disease.