Absolute and relative risk of cardiovascular disease in men with prostate cancer: results from the Population-Based PCBaSe Sweden

Abstract

Purpose: Cardiovascular disease (CVD) is a potential adverse effect of endocrine treatment (ET) for prostate cancer (PC). We investigated absolute and relative CVD risk in 76,600 patients with PC undergoing ET, curative treatment, or surveillance.

Methods: PCBaSe Sweden is based on the National Prostate Cancer Register, which covers more than 96% of PC cases. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) of ischemic heart disease (IHD), acute myocardial infarction (MI), arrhythmia, heart failure, and stroke were calculated to compare observed and expected (using total Swedish population) numbers of CVD, taking into account age, calendar time, and previous CVD.

Results: Between 1997 and 2007, 30,642 patients with PC received primary ET, 26,432 curative treatment, and 19,527 surveillance. SIRs for CVD were elevated in all men with the highest for those undergoing ET, independent of circulatory disease history (SIR MI for men without circulatory disease history: 1.40 [95% CI, 1.31 to 1.49], 1.15 [95% CI, 1.01 to 1.31], and 1.20 [95% CI, 1.11 to 1.30] for men undergoing ET, curative treatment, and surveillance, respectively). Absolute risk differences (ARD) showed that two (arrhythmia) to eight (IHD) extra cases of CVD would occur per 1,000 person-years. SMRs showed similar patterns, with ARD of zero (arrhythmia) to three (IHD) per 1,000 person-years.

Conclusion: Increased relative risks of nonfatal and fatal CVD were found among all men with PC, especially those treated with ET. Because ET is currently the only effective treatment for metastatic disease and the ARDs were rather small, our findings indicate that CVD risk should be considered when prescribing ET but should not constitute a contraindication when the expected gain is tangible.