Mortality among people with cancer who survive at least five years after diagnosis is higher than for the general population, particularly in terms of cardiovascular disease-related mortality, according to research published in the Medical Journal of Australia.
Research led by Flinders University Professor Bogda Koczwara, a medical oncologist and senior staff specialist at the Flinders Medical Centre, analysed South Australian Cancer Registry data for all people diagnosed with cancer during 1990-1999 and alive five years after diagnosis, with follow-up to 31 December 2016.
Analysis of 32,646 people with cancer alive five years after diagnosis found:
- – 17,268 deaths were recorded (53% of patients; mean age, 80.6 years; SD, 11.4 years)
- – 7,845 were attributed to cancer (45% of deaths)
- – 9,423 were attributed to non-cancer causes (55%)
Ischaemic heart disease was the leading cause of death (2,393 deaths), followed by prostate cancer (1,424), cerebrovascular disease (1,175), and breast cancer (1,118).
The overall standardised mortality ratio (adjusted for age, sex, and year of diagnosis) was 1.24%.
The cumulative number of cardiovascular deaths exceeded that of cancer cause-specific deaths from 13 years after cancer diagnosis.
“Overall, 26.7% of all deaths and 56.1% of non-cancer deaths were attributed to cardiovascular diseases,” Professor Koczwara and colleagues conclude in their study.
“Our findings may partly reflect the high prevalence of and mortality from cardiovascular disease in Australia, but we also found that cardiovascular mortality was higher than in the general population.
“Our findings suggest an interaction between cancer or its treatment and cardiovascular risk factors. The interaction may reflect a biological phenomenon (such as a direct toxic effect of anti-cancer treatment on the heart or vascular system), or it may reflect lack of prioritisation of cardiovascular disease by patients or health care focused on treating cancer.”
“It is notable that cardiac failure was a relatively infrequent cause of death (2.2% of all deaths), suggesting that cancer treatment toxicity, which tends to cause cardiac failure, may lead to earlier mortality, which would not have been identified in this study of individuals who survived at least five years after diagnosis, with later mortality from cardiovascular disease driven more by existing risk factors and background population risk.”
The research concludes that cancer survivorship care should include early recognition and management of risk factors for cardiovascular disease.
“Cancer control systems should incorporate monitoring of long term survivorship outcomes, including non-cancer-related mortality, and manage risk factors for premature death from non-cancer causes,” says Professor Koczwara.
This study was supported by a Flinders Foundation Seeding Grant. Bogda Koczwara was supported by a National Breast Cancer Foundation Practitioner Fellowship and Robyn A Clark by a Heart Foundation Future Leader Fellowship.
