Clinical impact of multimodal treatment including chemoradiotherapy, conversion surgery and postoperative chemotherapy for borderline resectable and unresectable locally advanced pancreatic cancer without disease progression after gemcitabine plus nab-paclitaxel.

ABSTRACT

BACKGROUND: The purpose of this study was to investigate treatment outcomes of chemoradiotherapy (CRT) using S-1 with or without conversion surgery after gemcitabine plus nab-paclitaxel (GnP) for borderline resectable (BR) and unresectable locally advanced (UR-LA) pancreatic cancer. METHODS: From 2016 to 2020, patients without disease progression after GnP for BR or UR-LA pancreatic cancer underwent CRT with S-1. If distant metastasis was not detected after CRT, conversion surgery and oral administration of S-1 as postoperative adjuvant chemotherapy for at least 6 months was performed. RESULTS: Forty patients were included in the present study. The median number of cycles of GnP was 6. Surgery was performed after CRT in 25 patients. The median progression-free survival (PFS) and overall survival (OS) periods from the start of radiotherapy were 24.6 and 27.4 months, respectively. The OS periods from the start of radiotherapy in patients who underwent conversion surgery and those who did not undergo conversion surgery were 41.3 and 16.8 months, respectively. The PFS periods from the start of radiotherapy in patients who underwent surgery and those who did not undergo surgery were 28.3 and 8.6 months, respectively. Patients who were able to receive S-1 after conversion surgery for more than 6 months had better OS than those who were not (p = 0.039), although there was no significant difference of PFS (p = 0.365). CONCLUSIONS: In BR/UR-LA pancreatic cancer without disease progression after GnP, multimodal treatment including CRT, conversion surgery and the scheduled postoperative chemotherapy may be effective.