Analysis of Perioperative Chemotherapy in Resected Pancreatic Cancer: Identifying the Number and Sequence of Chemotherapy Cycles Needed to Optimize Survival

Purpose. Receipt of 6 cycles of adjuvant chemotherapy (AC) is standard of care in pancreatic cancer (PC). Neoadjuvant chemotherapy (NAC) is increasingly utilized; however, optimal number of cycles needed alone or in combination with AC remains unknown. We sought to determine the optimal number and sequence of perioperative chemotherapy cycles in PC. Methods. Single institutional review of all resected PCs from 2008 to 2015. The impact of cumulative number of chemotherapy cycles received (0, 1-5, and >= 6 cycles) and their sequence (NAC, AC, or NAC + AC) on overall survival was evaluated Cox-proportional hazard modeling, using 6 cycles of AC as reference. Results. A total of 522 patients were analyzed. Based on sample size distribution, four combinations were evaluated: 0 cycles = 12.1%, 1-5 cycles of combined NAC + AC = 29%, 6 cycles of AC = 25%, and >= 6 cycles of combined NAC + AC = 34%, with corresponding survival. 13.1, 18.5, 37, and 36.8 months. On MVA (P < 0.0001), tumor stage [hazard ratio (HR) 1.35], LNR (HR 4.3), and R1 margins (HR 1.77) were associated with increased hazard of death. Compared with 6 cycles AC, receipt of 0 cycles [HR 3.57, confidence interval (CI) 2.47-5.18] or 1-5 cycles in any combination (HR 2.37, CI 1.73-3.23) was associated with increased hazard of death, whereas receipt of >= 6 cycles in any sequence was associated with optimal and comparable survival (HR 1.07, CI 0.78-1.47). Conclusion. Receipt of 6 or more perioperative cycles of chemotherapy either as combined neoadjuvant and adjuvant or adjuvant alone may be associated with optimal and comparable survival in resected PC.