Obesity and prostate enlargement in men with localized prostate cancer

Study Type – Prevalence (retrospective cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? Obesity is associated with prostate enlargement in men without prostate cancer. This study demonstrates an association between obesity and prostate enlargement in men with prostate cancer, and leads to possible implications for prostate cancer screening and diagnosis.

OBJECTIVE

? To determine if obesity is associated with prostate size in men with prostate cancer.

PATIENTS AND METHODS

? We examined preoperative body mass index (BMI) and whole prostate weight in a cohort of 16 325 patients undergoing radical prostatectomy for localized prostate cancer from 1975 to 2008 at a single institution. ? We used multivariable regression modelling adjusting for age, year of surgery, preoperative serum prostate‐specific antigen (PSA), pathological stage and Gleason grade.

RESULTS

? Of the entire cohort, 13 343 (82%) patients had a prostate weight of at least 40 g. These men were older (P < 0.001), had a higher preoperative BMI (P < 0.002), higher preoperative PSA (P < 0.001), and were more likely to have pT2 disease (P < 0.001). ? In multivariable regression, preoperative BMI was associated with increased prostate weight: for each 1 kg/m² increase in BMI, prostate weight increased by 0.45 g (95% CI 0.35–0.55, P‐trend < 0.001). ? Compared with men with BMI < 25 kg/m², men with a BMI ≥35 kg/m² had a 40% (odds ratio 1.40, 95% CI 1.01–1.95) increased risk of prostate weight of at least 40 g and a 70% (odds ratio 1.70, 95% CI 1.32–2.20) increased risk of prostate weight of at least 50 g.

CONCLUSIONS

? In men with localized prostate cancer, obesity is associated with an increased risk of prostate enlargement. ? These data validate other observations linking obesity with prostate enlargement and may have important ramifications for prostate cancer diagnosis in obese men.