Reasons for delay in time to initiation of adjuvant chemotherapy (AC) for colon cancer (CC).

Abstract

548 Background: AC improves survival among patients with colon cancer. Two meta-analyses have demonstrated a decrease in survival with increasing time to AC (TTAC). In this study, we examined individual patient charts to determine reasons for delay in AC. Methods: Medical records of patients with CC who initiated AC Aug 2005-Nov 2010 at the Cancer Centre of Southeastern Ontario were reviewed to capture patient, disease, and treatment characteristics including: medical comorbidities, post-operative complications, whether AC was or was not ordered after initial consultation, and the reasons behind the decision. Dates of surgery, referral, consult, central venous catheter (CVC) insertion, and first cycle of AC were recorded. Patients were then categorized into Group 1-medical/surgical reason for delay (MSRD), defined as presence of post-operative complications or intercurrent medical illness, and Group 2–no MSRD. In Group 2, patients were further categorized as having a non-MSRD, defined as patients in whom AC was deferred at time of consultation due to patient preference and/or further investigations required, vs none. A multivariate logistic regression model was used to determine factors associated with TTAC > 8 weeks (w). Results: For 171 patients: Mean age - 67; 52% male; 79% stage 3; IV AC – 80%, Oral AC – 20%. TTAC for all cases was 8.3 ± 2.3w. Mean intervals ± SD between surgery and TTAC in weeks were: surgery to referral 3.1 ± 2.0; referral to consult 2.5 ± 2.3; consult to oral AC 2.0 ± 2.1; for IV AC, consult to CVC 2.2 ± 1.3, and CVC to AC 0.7 ± 0.8. TTAC did not differ between patients with comorbidities (N= 89) and those without (N=82), p= 0.64, but was greater for patients in Group 1 (N=41 with MSRD) vs Group 2 (N = 130), p= 0.002. In Group 2, 43.8% (N=57) had TTAC > 8w while only 20% of cases (n=26) had a non-MSRD. Factors associated with TTAC>8w were MSRD [OR=5.6 (2.3-13.7), p = <0.001] and non-MSRD [OR=6.7 (2.3-19.5), p = <0.001]. Conclusions: Although medical/surgical complications are a strong predictor of delayed TTAC, this only applies to a small proportion of cases. Accordingly, in most patients TTAC>8w is unrelated to their post-operative medical condition and likely reflects health system and logistical issues.