0923 GMT February 18, 2020
Higher rates of prostate cancer relapse, prostate cancer death, and death from other causes were seen for overweight and obese men in this study of more than 1,400 prostate cancer patients, HealthDay wrote.
"It isn't the weight per se, but there must be some association with increased weight that's making the treatment less effective," said lead researcher Dr. Eric Horwitz, chairman of radiation oncology at Fox Chase Cancer Center in Philadelphia.
"It's not that radiation doesn't work, but it doesn't seem to work as well," he said. "It's still better than not having any treatment."
Being overweight or obese was associated with a small, 3 percent, higher rate of prostate cancer relapse and a seven-percent higher rate of cancer spreading. Heavier patients also had a 15-percent increased rate of dying from their cancer and a five-percent greater rate of dying from other causes, the researchers found.
Obesity among US adults has more than doubled in the past four decades, according to the US Centers for Disease Control and Prevention. While obesity has been linked to certain other cancers, its association with prostate cancer isn't clear, the researchers explained in background notes.
Unlike thinner patients who might be candidates for surgical treatment, Horwitz said overweight and obese men with prostate cancer often have just one option: radiation.
The study involved 1,442 men, average age 68, treated with radiation therapy for localized prostate cancer between 2001 and 2010. They were followed for an average of four years.
One expert said that numerous theories have been floated to explain the poorer outcomes of obese men with prostate cancer.
"One biological mechanism for the worse survival outcomes among obese men is due to more rapid progression of the tumor to distant metastasis after treatments begin to fail,” said Dr. David Samadi, chairman of urology and chief of robotic surgery at Lenox Hill Hospital in New York City.