Seventy percent of men who received androgen-deprivation therapy after surgery to remove their prostate gland gained significant weight in the first year.
Seventy percent of men who received androgen-deprivation therapy (ADT) after surgery to remove their prostate gland gained significant weight in the first year, putting on an average of 4.2 kg, according to a paper in the March issue of the urology journal BJUI.
Researchers studied the recorded weights of 132 men who underwent radical prostatectomy between 1988 and 2009 at four US Veterans Affairs Medical Centers in California, Georgia, and North Carolina, before and after they received ADT. This showed that the majority of the men gained significant weight during the first year of therapy, but did not put on any more weight after that.
“ADT is a hormone therapy that deprives the patient’s body of androgens, such as testosterone, which have been shown to stimulate the growth of prostate cancer cells,” said Stephen J Freedland, MD, from the Duke Prostate Center at Duke University School of Medicine and the Veteran Affairs Medical Center, Durham, North Carolina.
“Having been established as the mainstay treatment for recurrent or secondary prostate cancer, ADT is now being increasingly used to treat localised disease,” Freedland said in a statement.
“This rising use of ADT makes it even more important that we pay close attention to the side-effects of the therapy, including weight gain, as obesity is linked with a number of chronic and potentially life-threatening health problems.”
Freedland teamed up with colleagues from four other US states to carry out the study, using data from the Shared Equal Access Regional Cancer Hospital database. Patients were included if there was sufficient information to track their weight before and after the use of ADT.
The average age of the men included in the study was 66 years; 50% were white, 42% were black, and 8% were from other races. Their average Body Mass Index before starting ADT was 29. The men’s weight was measured a median of 33 days before and 363 days after the start of their ADT therapy.
Key findings of the study included:
• 70% of the men gained weight, 26% lost weight and 4% stayed the same. The men who put on weight gained an average of 4.2 kg, while the men who lost weight lost an average of 2.4kg. The total weight gain averaged across all of the 132 men in the study was 2.2kg or 2.4% of their body weight.
• Data covering the year before ADT and the second year after ADT was available for 64% of the men. This showed that most of the significant weight gain took place in the first year after ADT therapy started. Their overall weight gain averaged 2.1 kg in the first year, with no change in the second year.
• Weight gainers and losers did not differ in any demographic, clinical, or pathological respects.
“Despite its clinical efficacy in advanced prostate cancer, ADT is associated with an array of adverse side effects such as insulin resistance and increased risk of cardiovascular disease,” said Howard Kim, a medical student at Duke University School of Medicine and first author of the study.
“A growing number of studies show that men receiving ADT undergo a shift in body mass composition, gaining weight by increasing body fat and losing bone density and lean muscle mass,” he added.
“The most notable finding of our study is that any significant weight gain tends to occur in the year after ADT therapy begins and then stabilizes after that. Previous studies have tended to concentrate on the short time frame immediately after ADT is initialized, whereas much of our data covers a three-year time-span. This has enabled us to provide a clearer picture, not only of how much weight patients can gain on ADT, but when any significant weight gain occurs.”