551P - Adjuvant Chemotherapy (AC) Use and Outcomes in Stage II Colon Cancer (CC) with vs. without Poor Prognostic Features

Abstract

ABSTRACT Background AC is frequently considered in patients (pts) with “high risk” stage II CC, defined by the presence of >/ = 1 poor prognostic features: obstruction or perforation, T4 stage, Methods All pts with stage II CC in British Columbia from 1999 to 2008 and evaluated at 1/5 regional centers were reviewed. Kaplan-Meier and Cox regression methods were used to correlate high vs low risk status and receipt of AC with relapse-free (RFS), disease specific (DSS) and overall survival (OS). Results We identified 1,697 pts: 1,236 (73%) high risk and 461 (27%) low risk among whom 363 (29%) and 61 (13%) received AC, respectively. Individuals with high risk disease who received AC were younger (median 62 vs 72 yrs p Conclusions In this population-based cohort study, AC was associated with an OS advantage in high risk pts, likely due to pt selection. RFS and DSS benefits were mainly seen in T4 lesions, suggesting a limited role for AC in pts deemed high risk. A possible trend towards harm was seen in the low risk group receiving AC. Risk stratification based on molecular testing should be further explored. Table 1: 3yr RFS % p value 5yr DSS % p value 5yr OS % p value High risk AC 78 0.98 80 0.83 75 No AC 80 79 68 Low risk AC 87 0.18 93 0.78 87 0.26 No AC 93 93 85 Disclosure All authors have declared no conflicts of interest.