Perspective on an Innovative Curative Strategy for Peritoneal Metastasis Involving Peritonectomy, Hyperthermic Intraperitoneal Chemotherapy, and Adjuvant Chemotherapy Identified as Effective in the Histoculture Drug Response Assay (HDRA).

Abstract

Background/aim: Peritoneal carcinomatosis is the end stage for patients with gastrointestinal cancer, with survival ranging between 2 and 9 months. Pancreatic acinar cell carcinoma (PACC) is rare and can result in peritoneal metastases. The efficacy of chemotherapy for patients with PACC is unknown, and a systemic treatment strategy has not been established. The aim of the present perspective is to discuss a potential curative strategy combining surgery, heated intraperitoneal chemotherapy (HIPEC), and the histoculture drug response assay (HDRA) to identify effective adjuvant chemotherapy for PACC with peritoneal metastases, based on a published case report.

Case report: A 31-year-old man with a 20 cm epigastric mass, diagnosed as PACC, had curative-intent resection of a tumor on the distal stomach and pancreas tail. The patient recurred after four courses of adjuvant oral S-1 treatment. Laparotomy demonstrated peritoneal metastases with a peritoneal cancer index of 18. Ascites or other cancer cells in the peritoneal wash were not found. Peritonectomy, combined with HIPEC with gemcitabine and docetaxel, was performed intraoperatively. Postoperative 3-dimensional histoculture of fragments of the resected tumor with drug response testing with the histoculture drug response assay (HDRA) showed gemcitabine had the highest tumor inhibitory rate (70%) among six drugs tested. Based on the HDRA results, the patient was treated with adjuvant systemic gemcitabine chemotherapy. The patient did not have a recurrence within 18 months after surgery.

Conclusion: The present innovative treatment of PACC with peritoneal metastases used laparotomy to determine the extent of peritoneal metastases, peritonectomy to attempt to completely remove the tumor, HIPEC for intraoperative hyperthermic-chemotherapy, and the HDRA to determine the most effective drug for adjuvant chemotherapy. These procedures can be individualized for each patient's cancer, and the HDRA is most critical for individualization.