Aims
Cancer survivors are at risk of late mortality but there is little population level data on mortality patterns. The aim of this study was to investigate causes of death for those who survived more than five years post-diagnosis and compare mortality rates to those expected for general population.
Methods
This was a retrospective cohort study of all individuals diagnosed with cancer in South Australia between 1990 and 1999 who survived five years after their cancer diagnosis. Survival analysis estimated the overall mortality and mortality by cancer diagnosis. The overall all-cause mortality was compared to the all-cause mortality of the general population of South Australia.
Results
A total of 32,646 individuals with cancer were included. The majority were Caucasian (92.8%) and 50.3% were male. The average age at cancer diagnosis was 60.3 years (SD=15.7), and mean age at death was 80.6 years (SD=11.4). At median follow-up of 17 years there were 17,268 (53%) deaths recorded with 7,845 (24%) attributed to cancer and 9,423 (29%) attributed to non-cancer causes. Ischaemic heart disease was the leading cause of death, followed by prostate cancer, cerebrovascular disease, and breast cancer. The age, sex and calendar year direct standardised mortality ratio was 1.24 (95% CI 1.22-1.25). The all-cause mortality risk increased significantly if patients were male (hazard ratio [HR]=1.28, 95% CI=1.23-1.34), older (compared to age < 40 year groups; HRs ranged from 2.07 to 26.24 from 40-49 years group to patient aged 80 years and over), Aboriginal (HR=1.46 compared with Caucasian), or had multiple tumours (HR=1.53). Cardiovascular deaths exceeded cancer cause-specific deaths after 13 years since cancer diagnosis.
Conclusions
Mortality rates for cancer survivors were higher than those expected for the general population with cardiovascular disease, a major cause of mortality. Survivorship care should include early recognition and management of risk factors for cardiovascular disease.