All-cause and cancer-specific death of older adults following surgery for cancer

Importance — Cancer care has inherent complexities in older adults, including balancing risks of cancer and noncancer death. A poor understanding of cause-specific outcomes may lead to overtreatment and undertreatment.

Objective — To examine all-cause and cancer-specific death throughout 5 years for older adults after cancer resection.

Design, Setting, and Participants — This population-based cohort study was conducted in Ontario, Canada, using the administrative databases stored at ICES (formerly the Institute for Clinical Evaluative Sciences). All adults 70 years or older who underwent resection for a new diagnosis of cancer between January 1, 2007, and December 31, 2017, were included. Patients were followed up until death or censored at date of last contact of December 31, 2018.

Exposures — Cancer resection.

Main Outcome and Measures — Using a competing risks approach, the cumulative incidence of cancer and noncancer death was estimated and stratified by important prognostic factors. Multivariable subdistribution hazard models were fit to explore prognostic factors.

Results — Of 82 037 older adults who underwent surgery (all older than 70 years; 52 119 [63.5%] female), 16 900 of 34 044 deaths (49.6%) were cancer related at a median (interquartile range) follow-up of 46 (23-80) months. At 5 years, estimated cumulative incidence of cancer death (20.7%; 95% CI, 20.4%-21.0%) exceeded noncancer death (16.5%; 95% CI, 16.2%-16.8%) among all patients. However, noncancer deaths exceeded cancer deaths starting at 3 years after surgery in breast, prostate, and melanoma skin cancers, patients older than 85 years, and those with frailty. Cancer type, advancing age, and frailty were independently associated with cause-specific death.

Conclusions and Relevance — At the population level, the relative burden of cancer deaths exceeds noncancer deaths for older adults selected for surgery. No subgroup had a higher burden of noncancer death early after surgery, even in more vulnerable patients. This cause-specific overall prognosis information should be used for patient counseling, to assess patterns of over- or undertreatment in older adults with cancer at the system level, and to guide targets for system-level improvements to refine selection criteria and perioperative care pathways for older adults with cancer.