The impact of obesity on overall and cancer specific survival in men with prostate cancer.

PURPOSE: We examined the impact of obesity on disease specific and overall survival in patients with prostate cancer.

MATERIALS AND METHODS: We identified 7,274 men from the Cancer of the Prostate Strategic Urological Research Endeavor database with clinically localized prostate cancer, known body mass index and clinicopathological disease characteristics. Patients were classified by body mass index as normal (less than 25 kg/m(2)), overweight (25 to 29.9 kg/m(2)), obese (30 to 34.9 kg/m(2)) and severely obese (35 kg/m(2) or greater). Associations between body mass index and need for secondary treatment, disease specific survival and overall survival were analyzed using univariate and multivariate models.

RESULTS: Patients were classified by body mass index category as normal (28.8%), overweight (50%), obese (16.4%) and very obese (4.8%). Mean followup was 51.3 +/- 38.5 months. During followup there were 1,044 deaths with 220 (21.1%) from prostate cancer. Stratified by body mass index category the groups differed with regard to the need for secondary treatment (p = 0.05) and overall mortality (p <0.01) but there were no significant differences with regard to disease specific survival (p = 0.09). On multivariate analysis age 65 to 74 years (HR 2.4, p = 0.002), age older than 75 years (HR 3.2, p = 0.0001), high risk disease (HR 1.6, p <0.0001), conservative treatment (HR 1.2, p <0.0001) and presence of diabetes (HR 1.6, p <0.0001) were associated with decreased overall survival. Only conservative treatment (HR 1.4, p <0.0001), high risk disease (HR 8.4, p <0.0001) and intermediate risk disease (HR 2.5, p = 0.004) were associated with decreased disease specific survival.

CONCLUSIONS: In a prospective, community based cohort we were unable to establish a relationship between body mass index and prostate cancer disease specific survival or overall survival.