The Association Between Cancer Incidence and Heart Failure: A Systematic Review and Meta-Analysis

Background/Objectives: Heart failure (HF) and cancers share common molecular and pathophysiological mechanisms. However, the association between HF and the risk of developing cancer remains unclear. This systematic review and meta-analysis evaluates the association between HF and the risk of cancer incidence by pooling data from studies that compared cancer incidence in HF patients with non-HF controls. Additionally, it quantifies pooled hazard ratios (HRs) for site-specific cancers. Methods: A systematic literature search was conducted across four databases until March 2025 (PROSPERO: CRD420251001541). Seven studies involving over 1.6 million participants were included. Three studies provided direct HF versus non-HF comparisons. Pooled HRs and their corresponding 95% confidence intervals (CIs) were calculated utilising random-effects models. Results: The pooled estimate for overall cancer in HF was not significant (HR 1.32; 95% CI: 0.94-1.85; p = 0.11). However, site-specific analyses revealed significantly elevated risks for lung cancer (HR 1.66; 95% CI: 1.27-2.16), urinary tract cancers (HR 1.66; 95% CI: 1.51-1.82), haematological cancers (HR 1.47; 95% CI: 1.12-1.94), and colorectal cancer (HR 1.38; 95% CI: 1.04-1.83). The associations with breast and prostate cancers were not significant. Notably, substantial heterogeneity was observed across most cancer sites (I² = 96-98%), apart from urinary tract cancers (I² = 0%). Conclusions: Although the pooled estimate for overall cancer was not significant, the significant findings for specific cancer sites suggest the need for enhanced cancer surveillance in patients with HF. Future research should focus on standardising definitions of HF, ensuring consistent adjustment for confounders, and stratifying data by HF phenotype.