Obesity worsens prognosis for men on early ADT

Among men receiving early androgen deprivation therapy (ADT) for biochemical recurrence after radical prostatectomy, obesity appears to be a significant risk factor for poorer prognosis, according to the results of a retrospective study presented yesterday.

The association between obesity and prostate cancer-specific outcomes in men treated with early ADT was investigated using the Shared Equal-Access Regional Cancer Hospital (SEARCH) database, which includes men treated at five U.S. Veterans Affairs hospitals. For the period from 1988 to 2009, 287 men receiving early ADT were identified, with a median follow-up of 73 months after surgery and 52 months after starting ADT.

They were stratified into three groups based on body mass index (normal, overweight, and obese). The three groups were similar with respect to traditional risk factors for progression, including the PSA value at the time ADT was started, the PSA nadir value after starting ADT, and the PSA doubling time prior to starting ADT.

Using Cox proportional hazards models, the authors found men who were overweight or obese had a three-fold higher risk for progression to castration-resistant prostate cancer compared to their counterparts with a normal BMI. Relative to the normal BMI reference group, risk for developing metastasis was increased by more than three-fold among overweight men and by five-fold among the obese men, reported first author Christopher Keto, MD, of Duke University Medical Center, Durham, NC. All of these differences were statistically significant, and the data also showed a trend for increased prostate cancer-specific mortality among obese men compared with the reference group.

"Now, further study is needed to confirm the associations we found between obesity and worse cancer-specific outcomes in men on early ADT after surgery," said Dr. Keto, who worked on the study with Stephen Freedland, MD, and colleagues. "If confirmed, the findings would support counseling obese patients about weight reduction through diet and exercise and suggest that urologists should consider being proactive about enrolling these patients in clinical trials."