Postoperative mortality in elderly patients with colorectal cancer: The impact of age, time-trends and competing risks of dying

Abstract

BackgroundWorse prognosis in elderly colorectal cancer (CRC) patients may be cancer or treatment related, or death from other causes. This population-based study aimed to compare survival among non-metastatic CRC patients between age groups and notice time trends in mortality rates. MethodsPrimary stage I-III CRC patients who underwent resection between 2008 and 2013 were selected from the Netherlands Cancer Registry. Patients were divided into three equally distributed age groups and a separated group including the oldest old (<65, 65–74, 75–84 and ≥ 85 years). Survival rates were calculated by age groups and tumour localization. Relative excess risks of death, 30-day, 1-year mortality and 1-year excess mortality were calculated. Results52296 patients were included. Age-related differences in 5-year overall survival were observed (colon cancer: 82%, 73%, 56% and 35%; rectal cancer: 82%, 74%, 56% and 38%; p < 0.0001). Age-related differences were less prominent in relative survival and disappeared in conditional relative survival (condition of surviving 1 year). Thirty-day mortality rates decreased over time (colon cancer: 4.9%–3.4%; rectal cancer: 3.0%–1.7%); 1-year mortality rates decreased from 11.9% to 9.6% in colon cancer and from 8.0% to 6.4% in rectal cancer. One-year excess mortality increased with age (17.3% and 12.9% in patients with colon or rectal cancer aged ≥85 years). ConclusionOne-year mortality rates remain high in elderly patients. Age-related differences in survival disappeared after adjustment for expected death from other causes and first-year mortality. Beneficial time trends in 1-year mortality rates underline that survival in elderly after CRC surgery is modifiable.