Significance of neoadjuvant therapy for borderline resectable pancreatic cancer: a multicenter retrospective study.

PURPOSE: Neoadjuvant therapy (NAT) is increasingly used to improve the prognosis of patients with borderline resectable pancreatic cancer (BRPC) albeit with little evidence of its advantage over upfront surgical resection. We analyzed the prognostic impact of NAT on patients with BRPC in a multicenter retrospective study.

METHODS: Medical data of 165 consecutive patients who underwent treatment for BRPC between January 2010 and December 2014 were collected from ten institutions. We defined BRPC according to the National Comprehensive Cancer Network guidelines, and subclassified patients according to venous invasion alone (BR-PV) and arterial invasion (BR-A).

RESULTS: The rates of NAT administration and resection were 35% and 79%, respectively. There were no significant differences in resection rates and prognoses between patients in the BR-PV and BR-A subgroups. NAT did not have a significant impact on prognosis according to intention-to-treat analysis. However, in patients who underwent surgical resection, NAT was independently associated with longer overall survival (OS). The median OS of patients who underwent resection after NAT (53.7 months) was significantly longer than that of patients who underwent upfront (17.8 months) or no resection (14.9 months). The rates of superior mesenteric or portal vein invasion, lymphatic invasion, venous invasion, and lymph node metastasis were significantly lower in patients who underwent resection after NAT than in those who underwent upfront resection despite similar baseline clinical profiles.

CONCLUSIONS: Resection after NAT in patients with BRPC is associated with longer OS and lower rates of both invasion to the surrounding tissues and lymph node metastasis.