Adjuvant chemotherapy improves survival amongst octogenarians following resection of colorectal adenocarcinoma

Background: The Australian population is ageing, with an increasing number of patients diagnosed with colorectal cancer in their eighth decade. This group represents a challenging cohort to deliver multidisciplinary care, with increased morbidity and mortality related to surgical and oncological therapies. This project aimed to compare surgical and oncological outcomes in octogenarian and non-octogenarian patients with colorectal cancer. Methods: A matched case–control retrospective review of a prospectively maintained institutional database of colorectal cancer patients treated between 2005 and 2021 was conducted. Patient demographics, treatment details, peri-operative complications, and long-term survival were reported. The primary outcome, cancer-specific survival, was investigated using time-to-event analysis and interrogated with multivariate regression. Results: There were 747 patients included in the study. There was no difference in five-year cancer-specific survival and recurrence-free survival between cohorts. Multivariate analysis for octogenarians confirmed a significant hazard signal associated with worsening cancer stage and a survival benefit associated with the administration of adjuvant therapy. However, we noted that stage-matched octogenarian patients received less adjuvant treatment compared to non-octogenarians. Conclusion: Octogenarians undergoing treatment for colorectal cancer have similar cancer-specific survival and recurrence-free survival to non-octogenarians. Our study demonstrates a survival benefit when adjuvant therapy is provided to octogenarians, despite only half of this cohort receiving therapy compared to their younger peers. Further research into adjuvant therapy with surgical resection for CRC in older Australians is required.