Effects of early discontinuation of adjuvant chemotherapy (EDAC) and the timing of treatment on outcomes in patients with early-stage pancreatic cancer (ESPC): Result from a population-based retrospective cohort study.

Abstract

694 Background: Although evidence suggests that a delay in initiation of adjuvant chemotherapy (AC) results in inferior outcomes in some cancers, little is known about its detrimental effects in patients with ESPC. Moreover, it is not known if EDAC has been associated with high risk of recurrence and poor survival. The current study aims to determine association between timing and completion of AC and outcomes in ESPC. Methods: Patients with ESPC who were diagnosed from Jan 2007 to Dec 2017 and underwent complete resection in the province of Saskatchewan were examined. Kaplan Meier methods and log rank tests were performed for survival analyses. Cox proportional multivariate analyses were performed for correlation with recurrence and survival. Results: A total 168 patients with ESPC were identified. 97 (57%) patients were excluded as they did not receive AC, were found to have metastatic disease, did not have curative surgery or had received preoperative chemotherapy. Of 71 eligible patients with median age of 69 years (IQR: 57-73), 52% were male, 31% had WHO performance status of 0 and 92% had a comorbid illness. 78% had pancreatic head tumor, 66% had T3 tumor and 63% had node-positive disease. Median time to start of AC from surgery was 73 days (IQR: 59-89). 32% were started AC within 60 days of surgery. 89% received single-agent chemotherapy and 25% received adjuvant radiation. 69% completed planned treatment. Median time to recurrence in group which completed treatment was 22 months (95%CI:15.8-28.2) vs. 9 months (3.3-14.7) if treatment was discontinued early (P < 0.001). Median overall survival of the group that completed treatment was 33 months (17.5-48.5) vs. 16 months (17.5-48.5) if it was stopped early (P < 0.001). On multivariate analysis, EDAC was significantly correlated with recurrent disease (HR = 3.0; 1.6-5.5), P = 0.0001 and inferior survival (HR = 3.2; 1.68-6.12), P < 0.001. No correlation between AC timing and survival was noted. Conclusions: Although timing of AC does not correlate with inferior outcomes, EDAC has been associated with high risk of recurrence and inferior survival in ESPC.