Coronary Artery Disease May Boost Risk of Prostate Cancer

Jean-Alfred Thomas II, MD

New data implicate coronary artery disease (CAD) as a possible risk factor for prostate cancer. Jean-Alfred Thomas II, MD, with Duke University Medical Center in Durham, North Carolina, and associates examined the relationship between CAD and overall prostate cancer risk and disease grade using data from 6729 men enrolled in the REduction by DUtasteride of Prostate Cancer Events (REDUCE) study.

The 4-year, phase III REDUCE study evaluated the 5α-reductase inhibitor dutasteride, 0.5 mg per day, for prostate cancer risk reduction in men with a prostate-specific antigen (PSA) of 2.5 — 10.0 ng/mL and a negative biopsy. Results of the secondary analysis showed that CAD was significantly associated with increased prostate cancer diagnosis.

Coronary artery disease and prostate cancer have been shown to share several modifiable and nonmodifiable risk factors including age, race, family history, and possibly diet, the researchers pointed out. However, few studies have looked at the relationship between CAD and prostate cancer risk. Studies that have addressed this issue have produced conflicting results and are possibly biased, given that men with chronic comorbidities such as CAD may be more likely to undergo cancer screening.

Regardless of PSA level, all participants in the REDUCE study were required to undergo 10-core transrectal ultrasound (TRUS)-guided prostate biopsies at 2 and 4 years. Upon enrollment, a comprehensive medical history was obtained including CAD, smoking history, medication use, and other medical comorbidities.

Overall, 547 (8.6%) men had a history of CAD. These men were significantly older and had higher body mass index, PSA, and larger prostate volumes, and were more likely to have diabetes, hypertension, and hypercholesterolemia and take aspirin and statins.

On multivariate analysis, CAD was associated with a 35% increased risk of prostate cancer (odds ratio [OR], 1.35; 95% CI, 1.08-1.67; P = .007), with increased risk of both low- (OR, 1.34; 95% CI, 1.05-1.73; P = .02), and high-grade disease (OR, 1.34; 95% CI, 0.95-1.88; P = .09). However, because the study included fewer men with high-grade disease, this latter association did not achieve statistical significance.

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Coronary artery disease and prostate cancer have been shown to share several modifiable and nonmodifiable risk factors including age, race, family history, and possibly diet.”

Thomas and colleagues said that if the observed association between CAD and prostate cancer is confirmed in future studies, research will then need to focus on identifying the “biological mechanisms by which CAD mediates this elevation in prostate cancer risk.” In addition, confirmation of such an association may mean that measures that are known to decrease CAD might also lower the risk of prostate cancer.

The investigators acknowledged that a lack of available data on markers of systemic inflammation, physical activity level, diet, and serial weight measurements is an important study limitation since these factors are thought to be important in both prostate cancer and CAD.

Thomas JA II, Gerber L, Bañez LL, et al. Prostate cancer risk in men with baseline history of coronary artery disease: results from the REDUCE study [published online ahead of print February 7, 2012]. Cancer Epidemiol Biomarkers Prev. 2012;21(4):576-581.