Conversion therapy for pancreatic cancer with peritoneal metastases using intravenous and intraperitoneal paclitaxel with S-1.

Combination chemotherapy consisting of systemic and intraperitoneal agents against peritoneal metastases from several types of cancer has shown promising results. We herein report a case in which combination therapy with intravenous and intraperitoneal paclitaxel with S-1 converted an unresectable pancreatic cancer with peritoneal metastases into a resectable one. The patient was a 65-year old woman with recurrent pancreatitis for 5 months. Endoscopic ultrasonography-guided fine-needle aspiration revealed minute epithelial masses composed of cells with irregular nuclei in the pancreatic body. The patient underwent abdominal surgery, but no excision was performed, as two peritoneal metastases in the bursa omentalis were detected. Combination therapy was initiated, consisting of intravenous and intraperitoneal paclitaxel with S-1 as a single-center clinical trial. The regimen consisted with 2-week administration of S-1 (80 mg per day) followed by 1 week of rest, intravenous paclitaxel 50 mg/m2, and intraperitoneal paclitaxel 20 mg/m2 by a peritoneal access device on days 1 and 8. Over the seven cycles of the chemotherapy, the primary lesion did not change in size, and peritoneal lavage cytology remained negative. After confirming the disappearance of the peritoneal lesions by exploratory laparoscopy, the patient underwent distal pancreatectomy combined with resection of the transverse mesocolon and stomach wall. Thus, the 2-way chemotherapy of intravenous and intraperitoneal paclitaxel with S-1 was well-tolerated and was able to convert pancreatic cancer with peritoneal metastases to resectable disease.