Survival benefit of intravenous and intraperitoneal paclitaxel with S-1 in pancreatic ductal adenocarcinoma patients with peritoneal metastasis: a retrospective study in a single institution.

BACKGROUND: We evaluated the clinical efficacy of intravenous (i.v.) and intraperitoneal (i.p.) paclitaxel (PTX) combined with S-1 in patients with chemotherapy-naïve pancreatic ductal adenocarcinoma (PDAC) with peritoneal metastasis.

METHODS: Forty-nine patients were diagnosed with peritoneal metastasis during 2007-2014; 29 received gemcitabine or S-1-based chemo(radio)therapy from 2007 to 2011 (control group), and the remaining 20 received i.v. (50 mg/m2 ) and i.p. (20 mg/m2 ) PTX on days 1 and 8, and S-1 at 80 mg/m2 per day for 14 consecutive days, followed by 7 days of rest from 2012 to 2014 (study group).

RESULTS: The median survival time in the study group was significantly longer than that in the control group (20 vs. 10 months, respectively; P = 0.004). At 1 year after initial treatment, a significant difference in ascites development on CT was found between the study (5/20 patients) and the control group (18/29 patients, P = 0.009). The frequency of objective response (9/20 patients) and conversion surgery (6/20 patients) in the study group was higher than those in the control group (8/29 and 2/29, respectively). Patients who underwent conversion surgery had improved survival in both groups.

CONCLUSION: Implementation of the S-1+i.v./i.p. PTX regimen was closely associated with improved overall survival in PDAC patients with peritoneal metastasis.