Intraperitoneal Paclitaxel Treatment for Patients with Pancreatic Ductal Adenocarcinoma with Peritoneal Dissemination Provides a Survival Benefit

SIMPLE SUMMARY: Pancreatic ductal adenocarcinoma (PDAC) with peritoneal dissemination is a highly lethal disease. Recently, promising activity of intraperitoneal chemotherapy with paclitaxel (i.p.-PTX) has been observed in patients with peritoneal dissemination. We conducted a retrospective comparative study to evaluate the clinical efficacy of i.p.-PTX combined with systemic chemotherapy versus standard systemic chemotherapy in PDAC patients with peritoneal dissemination. The median survival time was 10.2 months for patients in the standard therapy group and 17.9 months in the i.p.-PTX group; the difference between groups was statistically significant (p = 0.006). We have performed surgical resection (defined as conversion surgery) to responders to treatment. Conversion surgery was planned for 26% in the i.p.-PTX group and 8% in the standard therapy group. The median survival time (27.4 months) from initial treatment in patients who underwent conversion surgery was significantly longer than that in patients who did not undergo conversion surgery (11.3 months, p < 0.0001). Implementation of the i.p.-PTX regimen may improve survival in patients with PDAC with peritoneal dissemination. ABSTRACT: Background: Intraperitoneal chemotherapy using paclitaxel (i.p.-PTX) is expected to be a new therapeutic strategy for patients with pancreatic ductal adenocarcinoma (PDAC) and peritoneal dissemination. We evaluated the survival benefit of i.p.-PTX compared with standard systemic chemotherapy. Methods: Clinical data of 101 consecutive PDAC patients with peritoneal dissemination between 2007 and 2018 were analyzed. All patients were determined to have no other sites of distant organ metastasis to the lung, bone, or liver on contrast-enhanced CT imaging. Patients underwent staging laparoscopy or open laparotomy to confirm pathological evidence of peritoneal dissemination, and to exclude occult liver metastasis. Survival curves were estimated using the Kaplan–Meier method, and differences were compared using the log-rank test. Results: Forty-three patients were treated with i.p.-PTX (i.p.-PTX group) and forty-nine patients received standard systemic chemotherapy (Ctrl group). Nine patients did not receive any treatment (BSC group). The median survival time (MST) in the i.p.-PTX group was significantly longer than that in the Ctrl group (17.9 months vs. 10.2 months, p = 0.006). Negative peritoneal washing cytology was observed in 24 out of 43 patients in the i.p.-PTX group. The i.p.-PTX group tended to have a higher proportion of clinical responses than the Ctrl group (30% vs. 18%, p = 0.183). Conversion surgery was performed in 10 patients in the i.p.-PTX group and 2 patients in the Ctrl group after confirming disappearance of peritoneal dissemination with staging laparoscopy or open laparotomy (p = 0.005). The MST in patients who underwent surgical resection was significantly longer than that in patients who did not (27.4 months vs. 11.3 months; p < 0.0001). Conclusion: i.p.-PTX therapy provided improved survival in PDAC patients with peritoneal dissemination, and conversion surgery enhanced it in patients with favorable responses to chemotherapy. i.p.-PTX might become one of the treatment options to PDAC patients with peritoneal dissemination.