Critically, the reasons for the study patients’ obesity, or thinness, are not clear, Dr. Vinayak Wagaskar, a urologist at Mount Sinai’s Icahn School of Medicine in New York City explains.
He notes that BMI was measured only after the men had developed advanced cancer that was no longer responding to hormonal therapy — and not right after their prostate cancer diagnosis.
That’s important, in part, because certain treatments for prostate cancer — including hormonal therapy and steroid medications — can cause weight gain.
The patients’ weight could have been affected by additional medical conditions they had, according to Wagaskar.
He says the study brings up an “interesting concept,” but he stressed the need for more research — with men’s BMI measured at the time of diagnosis.
For the study, Dr. Nicola Fossati and colleagues at San Raffaele University in Milan looked at data on almost 1,600 men who’d been involved in previous clinical trials. All patients had metastatic prostate cancer that was not responding to hormonal therapy. Metastatic means it had spread to distant sites in the body.
While early-stage prostate cancer is highly treatable, metastatic cancer is different: About 30% of men with such advanced disease survive for five years, according to the American Cancer Society.
In this study, Fossati’s team found that men with a BMI of 30 or higher — the obesity threshold — were 29% less likely to die over three years than those with a lower BMI.