Effectiveness of Adjuvant Therapy in Patients with Pancreatic Cancer Who Underwent Neoadjuvant Therapy

Purpose Neoadjuvant therapy (NAT) is used to treat not only advanced pancreatic cancer but also resectable lesions. The present study investigated the effectiveness of postoperative adjuvant chemotherapy for patients with pancreatic cancer who underwent surgical resection after NAT. Methods Patients who underwent macroscopically curative resection after NAT for pancreatic cancer were enrolled. Adjuvant chemotherapy was defined as at least 1 cycle of planned chemotherapy within 3 months after the date of surgery and included S-1, gemcitabine, or both. We retrospectively examined the effect of adjuvant chemotherapy on overall survival (OS) and recurrence-free survival (RFS) as a function of patients’ clinicopathological factors. Results Ninety-seven patients were included in the study, of which 68 (70.1%) underwent adjuvant chemotherapy. Administration of adjuvant chemotherapy was significantly associated with prolonged OS and RFS in patients whose elevated levels of carbohydrate antigen 19-9 or duke pancreatic monoclonal antigen type-2 did not normalize after NAT. In patients with pathological lymph node metastasis, the administration of adjuvant chemotherapy was significantly associated with longer OS but did not improve PFS. Conclusions Postoperative adjuvant chemotherapy was associated with prolonged postoperative survival in patients with pancreatic cancer who did not sufficiently respond to NAT as judged by tumor marker expression.