High BMI linked to poor outcomes after prostatectomy and ADT
MedWire News: Men initiating androgen deprivation therapy (ADT) after radical prostatectomy (RP) are more likely to experience poor outcomes if they are overweight or obese, report researchers.
In a retrospective review of 287 men who started ADT after undergoing RP, the team found that those with a higher body mass index (BMI; =25 kg/m2) were more likely to progress to castration-resistant prostate cancer (CRPC), metastases, and prostate-cancer-specific mortality (PCSM) than normal-weight men.
"If confirmed in larger studies, our results can help guide clinicians in risk stratification of men undergoing ADT based upon BMI," write Joseph Presti (University of California, Los Angeles, USA) and colleagues.
As reported in BJU International, during a mean follow-up period of 52 months after the men had started ADT, 44 progressed to CRPC, 34 developed metastases, and 24 died from prostate cancer.
Multivariate analysis showed that higher BMI was associated with a trend for a greater risk for progression to CRPC, with overweight and obese men over three times more likely to progress to CRPC than normal-weight men.
Similarly, a higher BMI was also associated with an increased risk for PCSM, although the number of prostate cancer deaths was modest, and did not reach significance.
Furthermore, a higher BMI was significantly associated with an increased risk for metastases, with the overweight and obese men three to five times more likely to develop metastases than normal-weight men.
Presti and colleagues say there are several potential explanations behind their findings.
Firstly, the effects of ADT may be reduced in overweight men due to an increased volume of drug distribution and therefore lower blood/tissue concentrations that may not fully suppress testosterone secretion.
Secondly, given that obesity is associated with lower levels of testosterone prior to ADT, it is plausible that these tumors are primed for ADT resistance and selected to grow in this low-testosterone environment.
"If confirmed, these data suggest that obese men starting ADT should be counseled regarding lifestyle modifications to promote weight reduction, the potential need for additional [prostate cancer] therapies and consideration of clinical trials," concludes the team.
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By Sally Robertson