Among men receiving early androgen deprivation therapy for biochemical recurrence after radical prostatectomy, obesity appears to be a significant risk factor for poorer prognosis.
Washington-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 at the AUA annual meeting.
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.
"This study has the inherent limitations of a retrospective study, but its strength is that it includes a very homogenous patient population of men all receiving early ADT for recurrence after surgery," said first author Christopher Keto, MD, a urologic oncology fellow at Duke University Medical Center, Durham, NC.
Further study needed to confirm links
"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. 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," Dr. Keto said.
"A phase II randomized controlled trial is under way enrolling overweight and obese men starting ADT to investigate the effects of dietary intervention to cut carbohydrates on metabolic markers, including insulin, which has been shown to be important in prostate cancer," Dr. Freedland told Urology Times. "If the results show positive effects of lifestyle modification, the next step will be to investigate if this approach alters cancer outcomes. Although I would like to believe there is benefit, evidence is still needed from well-designed clinical trials."
Further research is also needed to provide an explanation for the observed association between obesity and poorer prognosis in men on early ADT, although one small previous study of men on ADT showed that testosterone levels were significantly higher among obese versus non-obese men and thus suggests one possible mechanism, Dr. Keto noted.
"We could not investigate the possibility of suboptimal androgen suppression in obese men because data on testosterone levels was unavailable for all men. However, if this mechanism is confirmed, then perhaps dosing based on weight and/or laboratory monitoring, rather than using a fixed regimen, could be a solution," he said.