Cardiovascular disease (CVD) is the leading cause of death worldwide. With improved cancer treatment and survivorship, CVD and other non-cancer events compete with cancer as the underlying cause of death. However, their mortality risk in competing risk settings is not well characterised.
We identified 21,637 individuals with a first cancer registered between January 2006 and December 2013 in the population-based Tasmanian Cancer Registry, Australia. Cumulative incidence functions were applied to assess the cumulative incidence of deaths due to specific competing events with follow-up to December 2015. Standardised mortality ratios (SMRs) and absolute excess risks (AERs) for non-cancer deaths were calculated to allow comparison with the general population.
Overall, 8,844 deaths were observed with 1,946 (22.0%) from competing events (332 from subsequent cancer, 741 from CVD and 873 from other non-cancer events). The cumulative incidence of deaths due to CVD increased significantly with age at first cancer diagnosis (5-year cumulative mortality by age group: 15-64y – 0.7%; 65-74y – 2.1%; 75-84y – 6.0%; 85+y – 13.1%) and exceeded other competing events for those with a first cancer diagnosis at age 65 years or older. For the whole follow-up period, CVD deaths were as expected for the general population (SMR, 0.97; 95%CI 0.90-1.04), however within the first follow-up year, CVD deaths were more common than expected (SMR, 1.44; 95%CI 1.26-1.64; AER, 36.8/10,000 person-years). The SMR and AER for CVD deaths varied by first cancer sites showing an increased risk after a first diagnosis of lung cancer, haematological malignancies and urinary tract cancers. For other non-cancer events, the SMRs significantly increased for infectious disease and respiratory disease for the whole follow-up and within the first year of diagnosis.
CVD was the leading cause of competing mortality among Tasmanian cancer patients diagnosed from 2006-2013. The higher than expected risk of death due to CVD and other non-cancer events was greatest during the first year after cancer diagnosis highlighting the importance of early preventive interventions.
Clinical trial identification
Legal entity responsible for the study
Menzies Institute for Medical Research, University of Tasmania.
Has not received any funding.
All authors have declared no conflicts of interest.