A Duke University Medical Center study has concluded that obese men who have type 2 diabetes are almost four times as likely to be diagnosed with high-grade prostate cancer during a prostate biopsy as men who do not have diabetes. When ethnicity is taken into account, obese white men run a five-times greater chance of being diagnosed with high-grade prostate cancer.
Duke researchers studied 1,031 men who were undergoing their first prostate biopsy at the Durham VA Medical Center in North Carolina. At the time of their biopsies, 290 of the patients had diabetes. Researchers found that obesity in the diabetic patients increased their risk of receiving a high-grade diagnosis an average of 3.76 times over of that of non-diabetic men.
“High-grade” prostate cancer is defined as a value of 7 or more on the 10-point Gleason scale. The scale was developed to grade the similarity/dissimilarity of prostate cancer cells to normal prostate cells. The lower the number on the scale, the closer to normal the cells are and the less likely they are to metastasize. (The scale runs from 1 to 5, with 1 being the least aggressive and 5 being the most aggressive and likely to metastasize.)
A Gleason scale score incorporates values taken from the two largest areas of cancer cells detected in the prostate biopsy-the better to get an accurate idea of the cancer’s aggressiveness. A grade of 2 to 4 is “low,” a grade of 5 through 7 is “intermediate,” and a grade above 7 is “high.”
The study did not find a connection between diabetes and an overall risk for prostate cancer-in other words, no one can say that having diabetes is a precondition for developing prostate cancer. It also found that non-obese men with diabetes did not run a significantly increased risk of a high score on the Gleason scale. However, it did conclude that diabetes in general is associated with a twofold increased risk of receiving a high-grade score.
Prostate cancer is usually a slowly developing and often treatable form of the disease, so many patients with a low Gleason score have a reasonable expectation of living out a normal lifespan without the cancer metastasizing and moving into other areas of the body.
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