Sex differences in cancer incidence and mortality in patients with cardiovascular disease: the European Prospective Investigation into Cancer-Norfolk study.
BACKGROUND AND AIMS The incidence of cancer in people with cardiovascular disease (CVD) is poorly understood. This study aimed to understand the sex differences in incident cancer and cancer-related mortality in people with and without CVD. METHODS Participants were drawn from the European Prospective Investigation into Cancer (EPIC)-Norfolk study and followed up for a median of 26.2 years. Participants were stratified by sex and incident CVD during follow-up. Cumulative cancer incidence was calculated for each group. Sex-specific lifetime risks of cancer were determined, accounting for competing risks of death. Cause-specific hazard ratios (HRs) were determined using Royston-Parmar models, adjusted for ethnicity and time-updated covariates, including deprivation index, cardiovascular risk factors, comorbidities, and medication. Participants' CVD status was updated throughout follow-up. RESULTS A total of 22 534 participants were cancer-free at baseline (57% women; mean age 58.6 ± 9.3 and 59.5 ± 9.3 for women and men, respectively); 10 889 participants either had prevalent CVD at baseline or developed CVD during follow-up. Men had more comorbidities. The adjusted lifetime risk of incident cancer in CVD participants at age 75 was higher in men (17.3%) than in women (12.8%), with a significant cause-specific HR of 1.39 (99% confidence interval [CI] 1.25-1.53, P < .0001). Corresponding data for participants with no CVD were 10.2% for men and 8.2% for women, with an HR of 1.27 (99% CI 1.15-1.41, P < .0001 for men vs women). A similar trend exists for cancer-related mortality (HR 1.51, 99% CI 1.31-1.75, P < .0001 for men with CVD and HR 1.31, 99% CI 1.14-1.50, P < .0001 for men without CVD). CONCLUSIONS This study showed an increased lifetime cancer risk and mortality in men compared with women, which was mediated by comorbid CVD.