Survival benefit of conversion surgery for patients with initially unresectable pancreatic cancer who responded favorably to nonsurgical treatment

BACKGROUND: Conversion surgery (CS) is expected as a new therapeutic strategy for patients with unresectable pancreatic cancer (UR-PC). We analyzed outcomes of CS for patients with UR-PC and evaluated the survival benefit of CS. METHODS: Thirty-four patients diagnosed with UR-PC according to the National Comprehensive Cancer Network guideline underwent CS in our hospital. Resectability was considered by multimodal images in patients who underwent nonsurgical treatment (NST) for more than 6 months. CS was performed only in patients who were judged to be able to undergo R0 resection. RESULTS: Twenty-six patients had locally advanced PC, and eight had distant metastases. The median duration of NST was 9 (range 5-44) months. R0 resection was achieved in 30 patients (88.2%). Six patients (17.6%) showed Evans grade ≥III. Three- and 5-year overall survival (OS) rates from initial treatment were 74% and 56.9%, respectively, with median survival time (MST) of 5.3 years. The actual 5-year OS rate in 19 patients was 47.4% with an MST of 4.0 years. Patients with Evans grade ≥III had a better prognosis than those with Evans grade