Cancer as an independent mortality risk in chronic thromboembolic pulmonary hypertension

Background: The management of chronic thromboembolic pulmonary hypertension (CTEPH) has advanced significantly in recent years, thereby improving patient prognosis. However, the impact of cancer on the outcomes of patients with CTEPH under current treatment remains unclear. This study aimed to investigate the prevalence of cancer in patients with CTEPH and determine how comorbid cancer affects their prognosis and clinical course. Methods: Data from an ongoing Japanese prospective cohort study were analyzed. Prevalence and primary cancer sites were evaluated. The association of a history of cancer with a composite endpoint, including all-cause death, lung transplantation, and worsening of CTEPH, as well as venous thromboembolism and bleeding events, was assessed. Results: Of the 1,270 patients in the cohort, 134 (10.6%) had a history of cancer, with the most common primary sites being the breast in women and the prostate in men. The incidence of composite outcome and all-cause death was higher in those with a history of cancer (p < 0.001, log-rank test). In the Cox proportional hazard model, age- and sex-adjusted hazard ratios for the composite outcome and all-cause death were 2.69 (95% confidence interval, 1.48–4.89, p = 0.001) and 4.25 (95% confidence interval, 1.98–9.10, p < 0.001), respectively, for patients with a history of cancer. No significant differences in venous thromboembolism and bleeding events were observed between patients with and those without a history of cancer. Conclusions: A history of cancer, with a prevalence of 10.6%, is an independent risk factor for mortality in patients with CTEPH undergoing the currently recommended treatment.