New findings presented today at the 47th Annual Meeting of the American Society for Therapeutic Radiology and Oncology in Denver, Colorado say that there is no direct link between the presence of type II diabetes and the aggressiveness of prostate cancer, but the long-term survival rate is worse.
Researchers at Fox Chase Cancer Center found no correlation between the presence of high levels of insulin in the blood and the subsequent intensity of prostate cancer. Previous studies had suggested that insulin triggered the development of aggressive prostate cancer. "We looked at several key pretreatment factors used to stage the prostate cancer. These factors include the initial PSA, Gleason score and T-stage. The men with type II diabetes didn't have a significantly different initial profile for their prostate cancer than the men without diabetes," said Khanh H. Nguyen, M.D., lead author of the Fox Chase study and a resident in the radiation oncology department at Fox Chase. The study tracked 1,512 men with localized prostate cancer who had been treated with radiation therapy between April 1989 and October 2001. Of these 1,306 men had no history of type II diabetes, while 206 men had diabetes that was managed with diet, medication and exercise. Researchers found that patients without diabetes had a PSA failure rate of 27.2 percent at 5 years as compared to 23.8 percent in diabetes cases. Also 3.1 percent of the non-diabetic patients died of prostate cancer while 2.4 percent of diabetic patients succumbed to it.
"Despite laboratory and epidemiological data suggesting an effect of insulin on prostate cancer growth, in our patient cohort, diabetes did not appear to influence the aggressiveness of prostate cancer at presentation," concluded the researchers.