Background: Research suggests that EPs with cancer are commonly undertreated, but the precise reasons for this observation are unclear. Our aims were to 1) evaluate the impact of advanced age on AC use (none vs capecitabine vs FOLFOX) for stage III CC, 2) determine the specific reasons for selecting and discontinuing a particular regimen, and 3) examine if the effect of AC on outcomes is modified by age. Methods: Patients diagnosed with stage III CC from 2006 to 2008 and referred to any 1 of 5 cancer centers in British Columbia, Canada were identified. Descriptive statistics were used to summarize treatment patterns in young patients (YPs) aged <70 vs EPs aged >/=70 years. Logistic regression was used to evaluate the association between AC and cancer-specific survival (CSS) in YPs and EPs. Results: We identified 810 patients: 51% men, 52% YPs and 48% EPs, and 74% received AC in the entire cohort. When compared to YPs, EPs had worse ECOG and more comorbidities (both p<0.01). EPs were less likely than YPs to receive AC (57 vs 91%, p<0.01). Frequent reasons for no treatment included age, comorbidities and perceived minimal benefit from AC. Among those treated with AC, EPs were less likely to receive FOLFOX (32 vs 74%, p<0.01) in favor of capecitabine due to patient preference, age and comorbidities. Once started on AC, EPs had similar rates of early treatment discontinuation as YPs (70 vs 62%, p=0.08). Reasons for early discontinuation were comparable between EPs and YPs (Table). Receipt of either FOLFOX or capecitabine was correlated with improved CSS, compared to surgery alone. Age did not modify CSS, irrespective of AC choice (interaction p for capecitabine and age=0.26; interaction p for FOLFOX and age=0.40). Conclusions: EPs with stage III CC frequently received either no adjuvant treatment or capecitabine monotherapy due to advanced age and comorbidities. The treatment effect of AC on CSS is similar across age groups, with comparable side effects and rates of discontinuation between EPs and YPs. AC should not be withheld from CC patients based on advanced age alone.

	Reasons for early discontinuation
	Side effects	p	Progressive disease	p	Patient choice	p
YPs	59%	0.99	21%	0.39	6%	0.27
EPs	58%		16%		10%