Effect of time to initiation of adjuvant chemotherapy on survival in resected pancreatic cancer.

Abstract

368 Background: Pancreatic cancer carries a grim prognosis. Surgical resection followed by adjuvant chemotherapy is standard of care, but little is known about the temporal relationship of chemotherapy initiation and survival. This study analyzed the impact of time to initiation of adjuvant chemotherapy on survival in patients with resected pancreatic cancer. Methods: The National Cancer Data Base (2003-2011) was retrospectively reviewed for patients with clinical stages 1-3 resected pancreatic carcinoma. Time to chemotherapy was stratified at the 12-week post-operative timepoint. Univariate statistics, Kaplan-Meier estimates, and Cox proportional hazard modeling were performed. Results: 5,205 patients who had undergone surgical resection alone, 3,144 patients who had undergone surgical resection and adjuvant chemotherapy initiated at or before 12 weeks, and 906 patients who had undergone surgical resection followed by adjuvant therapy started after 12 weeks were included. Patients who received chemotherapy > 12 weeks tended to be older, have more co-morbidities, receive treatment at academic centers, and undergo whipple procedures. In all pathologic disease stages, adjuvant chemotherapy conferred a significant survival benefit over surgical resection alone (p < 0.0001). However, there was no significant overall survival benefit for patients receiving adjuvant chemotherapy before 12 weeks as compared to after (p = 0.85). When stratified by pathological stage, there was still no significant survival benefit for earlier initiation of chemotherapy (£ vs. > 12 weeks): stage I, p = 0.16, stage II, p = 0.12, stage III, p = 0.38. After controlling for patient, disease, and surgery characteristics, patients who received adjuvant chemotherapy after 12 weeks had a 31% lower odds of mortality at 5 years, while those who initiated it before 12 weeks had a 34% lower odds (p < 0.0001, p < 0.0001 respectively), versus surgery-alone. Conclusions: Earlier initiation of adjuvant chemotherapy does not significantly impact long-term survival in patients with resected pancreatic cancer. However, because adjuvant chemotherapy confers a survival benefit, delayed chemotherapy should be offered when appropriate.