ATLANTA – Here's another reason for men to avoid packing on extra pounds over the holidays: A new study has found that losing weight reduces the risk of an aggressive form of prostate cancer.
After tracking the weight of nearly 70,000 men between 1982 and 1992, researchers from the American Cancer Society and the Duke University Prostate Center found that men who lost more than 11 pounds had a lower risk for aggressive prostate cancer than men whose weight remained the same over a decade.
Previous studies have found that obese men have a higher risk of developing aggressive prostate cancer. This study appears to be the first to indicate that recent weight loss can decrease that risk.
In the study reported this month in Cancer Epidemiology, Biomarkers & Prevention, researchers analyzed the height and weight of the men in 1982 and 1992 and every three years after that until 2003. At that time, more than 5,200 of the men — more than 7 percent — had prostate cancer.
Among those cases, about one in eight had a form of cancer that was aggressive but had not spread to other areas of the body. The study's major finding focused on those aggressive cases, with researchers concluding that those who lost 11 or more pounds were 42 percent less likely to develop that form of prostate cancer than those whose weight remained the same.
"Whether it's exactly 40 percent, we don't know, but they lower their risk when they lose 11-plus pounds. We feel confident, at least in this population, that was real," said lead researcher Dr. Carmen Rodriguez.
More than seven times as many men whose weight remained the same developed aggressive prostate cancer compared to those who lost 11 or more pounds.
"No significant associations" were found regarding the effect of weight gain or loss on the most severe forms of prostate cancer, those that spread throughout the body, the study said.
The number studied was small, the researchers acknowledged, because fewer than 15,000 men lost weight over the time period, and only 1,000 of those developed some form of prostate cancer.
The 69,991 participants were part of a bigger cancer society study of 1.2 million Americans that began in 1982.
Rodriguez said men should avoid putting on extra weight as they get older.
"The main message for men is to not get overweight. If they are overweight, that's another reason to try to lose weight, just to decrease the risk for prostate cancer," said Rodriguez, who works for the Atlanta-based cancer society.
Other than skin cancer, prostate cancer is the most commonly diagnosed cancer for men, and about one in six will get it during his lifetime. It is the second leading cause of cancer death for U.S. men.
The study is considered the first of its kind to examine the role of weight change in the development of prostate cancer, said Dr. Ronald Ennis, director of radiation oncology at St. Luke's-Roosevelt Hospital Center in New York, who was not involved in the study.
"This is one of the best studies" examining the role of weight on prostate cancer, Ennis said. "It does seem to be true that if you are overweight, you are at risk of getting more aggressive forms of prostate cancer and if you lose weight, you can decrease the risk."