Adjuvant therapy use and outcomes of stage II and III colorectal cancer (CRC): Comparison of young and elderly patients (pts) in a large, contemporary, population-based Canadian database.

807 Background: The incidence of CRC increases significantly with age. Despite the benefits associated with adjuvant therapy, older pts are frequently treated less aggressively due to perceived poor tolerance to treatment, comorbidity, or limited life expectancy. We aim to examine the impact of chronological age on use of perioperative therapies in a contemporary cohort of pts and determine differences in outcomes based on age. Methods: Adult pts who underwent surgical resection for stage II or III CRC in Alberta, Canada from 2004 to 2015 were analyzed. Pts were stratified based on pre-specified age sub-groups. Overall survival (OS) and cancer specific survival (CSS) were assessed using the Kaplan-Meier method and compared with the log-rank test. A Cox proportional hazards model was constructed to evaluate the impact of age on outcomes. Results: We identified 8,538 pts of whom 56% were men, 53% had stage III disease, and 26% had rectal cancer. Older pts were more likely diagnosed with right-sided tumors, earlier stage, and higher Charlson comorbidity index (CCI) (all p <.01). Chemotherapy (CT) use decreased significantly with advancing age, even in recent years (Table). Older rectal cancer pts were also less likely to receive radiation (p <.01). Elderly age was the strongest predictor for not using CT, after adjusting for sex, stage, tumor location, and CCI. On multivariate Cox regression, older age was associated with inferior OS and CSS, but CT improved outcomes. Conclusions: Despite evidence of benefit and prior studies recommending treatment of elderly, the current cohort of older pts with resected stage II and III CRC continue to undergo perioperative therapy less commonly than their younger counterparts. [Table: see text]