Neoadjuvant Chemotherapy for Pancreatic Adenocarcinoma Lessens the Deleterious Effect of Omission of Adjuvant Chemotherapy

Background. Despite controversy regarding the role of neoadjuvant chemotherapy (NAC) in pancreatic adenocarcinoma, nearly half of resected patients do not receive chemotherapy postoperatively. This study aimed to examine whether use of NAC compensates for omission of adjuvant chemotherapy (AC) for resected pancreatic adenocarcinoma. Methods. Adults with resected stages 1 to 3 pancreatic adenocarcinoma were enrolled from the National Cancer Database NCDB (2006-2016). Overall survival (OS) analyses were used to examine the impact of NAC on those who did not receive AC. Results. The study analyzed a national cohort of 56,286 patients: 30% without chemotherapy, 11% with NAC, 54% with AC, and 5% with NAC plus AC. Use of NAC increased by more than 400% from 2006 to 2016, whereas the rates for omission of chemotherapy remained unchanged. The OS rates were similar between the patients who received NAC and those who received AC (hazard ratio, 0.97; p = 0.21). Among the patients who did not receive AC, NAC was associated with improved OS (26.7 vs. 18.4 months; p < 0.0001). The patients who did not receive AC but underwent NAC had a median OS comparable with the OS of those who received AC alone (26.9 vs. 24.7 months). In the adjusted analysis, the use of NAC for those without AC was significantly associated with improved OS (estimate, - 0.24; p < 0.0001). Conclusions. Although data are limited regarding the survival benefit derived from neoadjuvant versus adjuvant chemotherapy in pancreatic adenocarcinoma, nearly half of patients do not receive adjuvant chemotherapy. This study demonstrates that the use of NAC lessens the survival disadvantage caused by omission of AC. Despite controversy, NAC may be considered for pancreatic adenocarcinoma patients given the high likelihood that adjuvant chemotherapy will be omitted.