Adjuvant chemotherapy (AC) outcomes in young (YP) and elderly patients (EP) with high-risk stage II colon cancer (CC).

Abstract

3569 Background: High-risk stage II CC is defined as those presenting with T4 stage, obstruction or perforation, <12 lymph nodes retrieved, positive resection margins, and lymphovascular or perineural invasion. Our prior findings suggest that improved outcomes from AC are limited to specific high risk features, such as T4 disease (Kumar et al, ASCO 2012). It is unclear if this benefit is seen across all ages. Our aim was to compare patterns of AC use and outcomes in YP and EP with high risk stage II CC. Methods: All patients diagnosed with high risk stage II CC from 1999 to 2008 and evaluated at any 1 of 5 regional cancer centers in British Columbia were categorized into YP (age <70 years) or EP (age >/=70 years). Kaplan-Meier methods and Cox regression were used to correlate receipt of AC with overall survival (OS), disease specific (DSS) and relapse free survival (RFS), stratified by age group. Results: A total of 1,236 patients were identified: 636 (51%) YP and 600 (49%) EP among whom 363 (57%) and 85 (14%) received AC, respectively. Individuals who received AC in either age group had better performance status than those who did not (ECOG 0/1 47% vs. 34%, p=0.02). After adjusting for known prognostic factors, a significant advantage in OS, but not DSS or RFS, from AC was observed for both YP and EP (Table). The impact of AC on these outcomes was similar across age groups (p interaction of age and treatment = 0.46, 0.64 and 0.69 for OS, DSS and RFS, respectively). In the entire cohort, individuals with T4 lesions had significantly improved OS (HR 0.50, 95%CI 0.33-0.77, p=0.002), DSS (HR 0.59, 95%CI 0.37-0.93, p=0.03), and RFS (HR 0.63, 95%CI 0.42-0.95, p=0.03). The effect of AC in the T4 subgroup was also similar for both YP and EP in terms of OS, DSS and RFS (p interaction of age and treatment = 0.41, 0.71 and 0.77, respectively). Conclusions: In this population-based cohort of high risk stage II CC, improvements in outcomes from AC were seen mainly in those with T4 disease, regardless of age. [Table: see text]