New research shows that patients with type 2 diabetes have a lower risk of having prostate cancer.
It has long been understood that diabetes is a major risk factor for attaining certain cancers since they share so many characteristics. For example, age is a major proponent in developing many cancers and diabetes because as you get older, risk of both type 2 diabetes and cancer goes up. Another example is the link between smoking, alcohol abuse, being overweight and a general lack of inactivity. However, contrary to this popular belief, recent studies have gone to counteract this notion by suggesting that in fact type 2 diabetes may reduce the risk of prostate cancer (PCa).
According to a nearly four-year retrospective, population-based cohort study reported in Cancer Epidemiology, researchers followed men from ages 65 to 74 who were diagnosed with type 2 diabetes of and found that they had an overall 27 percent decrease in risk of prostate cancer than patients who were non-diabetic. There were a total of 32,247 type 2 diabetic patients and 1,018,518 people without diabetes. The research was obtained from health-related databases that encompassed the entire population living in the Friuli Venezia Giulia region in northern Italy. Follow-up with the patients was 3.65 years and there were a total of 2,069 documented cancer cancers, which had nearly 32,247 type two diabetes patients during the study period. For the patients with type 2 diabetes, the overall “risk of cancer at any site was 28 percent higher and the risks of bladder and kidney cancer were 36 percent and 47 percent higher compared with individuals who did not have type 2 diabetes. The risk of pancreatic cancer was 2.6 times higher.”
The reason that they found behind this possible inverse relationship was the reduction in androgen level among diabetic patients. The details behind the exact mechanism are still unclear and leave a lot of room for research. One plausible explanation is the metabolic and hormonal changes associated with diabetes, which could in turn explain the temporal relationship observed between the two conditions. Decreased levels of hormones and other cancer-related growth factors among diabetics, the overall impact of diabetes on detection-related factors such as prostate size, circulating prostate specific antigen (PSA) and health-care seeking behaviors are all contributing factors for the reduction of prostate cancer risk for many patients. Patients with diabetes typically tend to be examined by a healthcare professional from time to time–whether it’s for medication management or a generalized checkup to see how far the disease has progressed; these patients in particular are more inclined to get more frequent check-ups than patients who are non-diabetic. Therefore, the detection of prostate cancer is generally higher due to more routine visits to the doctor.
It is important to note that the study itself did look over a large population and used a database that covered an entire region, in turn making the study quite strong.
Limitations of the study include an overall lack of information on possible confounding variables, such as obesity and smoking habits, for many of the individuals included in the study. However, overall the results are definitely indicative of the fact that there is some plausible link between the two conditions and further research should be geared to finding out exactly why one condition affects the other and how that could potentially be used in the future to help patients with both ailments.
- Patients with type 2 diabetes are at a significantly reduced risk of having prostate cancer compared to non-diabetic patients.
- Having type 2 diabetes does not reduce the risk of attaining any other form of cancer.
- Further research needs to be done to determine the exact mechanism behind the phenomenon.
Researched and prepared by Javeria Fayyaz, Doctor of Pharmacy Candidate LECOM College of Pharmacy, reviewed by Dave Joffe, BSPharm, CDE
Bansal D, Bhansali A, Kapil G, Undela K, Tiwari P. Type 2 diabetes and risk of prostate cancer: a meta-analysis of observational studies. Prostate cancer and prostatic diseases. 16(2):151-8, S1. 2013.
Charnow, Jody A. “Prostate Cancer Risk Lower in Type 2 Diabetics.” Renal and Urology News. N.p., 15 Feb. 2016. Web. 20 Feb. 2016.
Pierce BL. Why are diabetics at reduced risk for prostate cancer? A review of the epidemiologic evidence. Urologic oncology. 30(5):735-43. 2012.