There’s No Link Between Diabetes and Aggressive Prostate Cancer

Type 2 diabetes has no effect on the aggressiveness of prostate cancer, but prostate cancer patients who are also diabetics do have poorer long-term survival rates, U.S. researchers report.
Previous studies had suggested that insulin promoted the growth of prostate cancer cells. In people with type 2 diabetes, the body fails to use insulin properly, which can result in excess insulin in the blood.
This study included more than 1,500 men with localized prostate cancer treated with radiation therapy between 1989 and late 2001. Of these patients, more than 1,300 had no history of type 2 diabetes, while about 200 did have type 2 diabetes managed with diet, exercise or medications other than insulin.
“We looked a several key pretreatment factors used to stage the prostate cancer,” study author Dr. Khanh H. Nguye, a resident in the radiation oncology department at Fox Chase Cancer Center, Philadelphia, explained in a prepared statement.
“These factors include the initial PSA (prostate-specific antigen), Gleason score and T-stage. The men with type 2 diabetes didn’t have a significantly different initial profile for their prostate cancer than the men without diabetes,” Nguyen said. “Additionally, type 2 diabetes did not appear to influence the rates of PSA failures or distant metastases. However, men with type 2 diabetes had significantly worse long-term overall survival.”
Among men with diabetes, the death rate from all causes was about 23 percent, compared to 19 percent for the men without diabetes. The death rates from prostate cancer were 3 percent for men with diabetes, and 2.4 percent for men without diabetes.
Even though diabetes doesn’t appear to influence the aggressiveness of prostate cancer, the use of diet, exercise and medications to control diabetes may improve the survival odds for prostate cancer patients, the study authors noted.