News | June 01, 2008

Weight, Not Diabetes, Related to Prostate Cancer Mortality

June 2, 2008 - Increased body weight increases the likelihood of prostate cancer-related death, not diabetes, reported new research from the Radiation Therapy Oncology Group (RTOG) presented at the American Society of Clinical Oncology’s 44th Annual Meeting in Chicago.

RTOG, an NCI-funded national clinical trial group and clinical research component of the American College of Radiology (ACR), also found that diabetic men with prostate cancer are no more likely to die from their cancer than are men who are not diabetic.

Recent research has shown that men with diabetes have a lower risk of developing prostate cancer. However little was known about the role of diabetes in those men who do develop prostate cancer. “Based on the results of our investigation, we now know that the real risk factor is not diabetes, but rather obesity,” said lead author Matthew Smith, M.D., Ph.D., of the Department of Medicine at Harvard Medical School. “We controlled for age, race, tumor stage, Gleason score, PSA, diabetes, weight and treatment assignment and found that weight, not diabetes, was the better predictor of prostate cancer mortality.”

Using data from a large randomized trial, RTOG 9202, of 1554 men treated with radiation therapy and short-term versus long-term adjuvant hormone therapy for locally advanced prostate cancer, RTOG investigators were able to look at the relationship between diabetes and cancer-related death, non-cancer-related death, and overall mortality. The researchers found that diabetes was significantly associated with deaths from all causes and deaths from non-prostate cancer-related causes, but not prostate cancer deaths. In contrast weight was associated with a higher incidence of prostate cancer deaths but not deaths from all causes or non-prostate cancer deaths.

“The RTOG is proud that our vast database enables researchers to compile and analyze data that can help extend and improve the lives of cancer patients. RTOG studies like this answer unique questions and further oncology research for the benefit of patients everywhere,” said Walter J. Curran, Jr., the RTOG Group Chair, and the Lawrence W. Davis Professor and Chair of the Department of Radiation Oncology in the Emory School of Medicine and Chief Medical Officer of the Emory Winship Cancer Institute.

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