Oncologic Outcome and Efficacy of Chemotherapy in Colorectal Cancer Patients Aged 80 Years or Older

Purpose: The present study aimed to evaluate the oncologic outcomes of patients 80 years or older compared with younger patients, and we then further investigated the efficacy of chemotherapy in individuals 80 years or older. Methods: A retrospective analysis was conducted using the Surveillance, Epidemiology and End Results database. The χ² test was used to analyze the different clinicopathologic and demographic variables between 65- and 79-year and ≥80-year groups. Kaplan-Meier analysis and log-rank testing were used to compare colorectal cancer (CRC)-specific survival (CCSS) curves between different groups. Multivariate and univariate Cox proportional hazards models with hazard ratios (HRs) and 95% confidence intervals (CIs) were also used to assess CCSS and OS. Results: A total of 189,926 patients were included in our study. Compared with 65- to 79-year-old patients, age 80 years or older was associated with 48.4% increased CRC-specific mortality (HR = 1.484, 95% CI = 1.453-1.516, P < 0.0001; using 65-79 years old as the reference). Moreover, not receiving chemotherapy was significantly associated with an increased risk of CRC-related death, independent of other prognostic factors (HR = 0.615, 95% CI = 0.589-0.643, P < 0.0001) in individuals 80 years or older. Conclusions: This large population-based study showed that older age was associated with worse oncologic outcomes compared to younger age. Chemotherapy could offer survival benefit for very old patients diagnosed with CRC, and we strongly believed that very old patients were undertreated in the present medical practices.