Uptake of adjuvant chemotherapy (AC) for colon cancer in older and younger patients (pts) in the Irish population.

Abstract

e14515 Background: The use of AC in older patients with colon cancer in clinical practice is uncertain. We examined uptake of AC and it’s impact on survival in older pts with stage II and III colon cancer in a national cohort. Methods: Using the National cancer Registry of Ireland, 3,486 pts with stage II and III colon cancer treated with curative resection from 2004-2009 were identified. Clinopathological features and AC use were compared between those ≥70 yrs and those < 70 yrs. Data from a single institution were reviewed to determine drivers of treatment decisions. Results: 2,026 pts with stage II disease were identified, 60% ≥ 70 yrs. AC was utilized in 10% and 40% of ≥ 70 and <70 yrs, respectively (p<0.0001). A benefit for AC over observation was seen in older [HR 0.36; p <0.0001] and younger pts [HR 0.43; p<0.0004]. Of 46 stage II pts from a single institution there were no significant differences between ≥ 70yrs (n=26) and <70yrs (n=23) in terms of ECOG PS, Charlson comorbidity scores (CCI), tumor grade, T3/T4 disease, R0/R1 resections, obstruction/perforation, lymphovascular invasion or nodal yield. However, only 12% ≥ 70yrs received AC compared to 57% of <70yrs (p=0.0002). Of 1,460 pts with stage III disease, 51% were ≥ 70 yrs. 34% of older and 83% of younger pts received AC (p<0.0001). A benefit from AC compared to observation was seen in pts ≥ 70yrs [HR 0.30; p <0.0001] and <70yrs [HR 0.22; p<0.0001]. Of 65 stage III pts from the single institution there were no differences in CCI, ECOG PS, tumor grade, R0/R1 resections between >70yrs (n=20) and <70yrs (n=45). There was a difference in those receiving AC: 75% ≥ 70yrs compared to 96% <70yrs (p=0.02). Conclusions: Adoption of AC is associated with a survival benefit in older pts (age ≥ 70 yrs), however, is still underutilized in clinical practice. Age impacts the decision to treat in our cohort.