Peritoneal carcinomatosis and radioimmunoguided surgery.

Abstract

The Radioimmunoguided Surgery (RIGS) system was developed, in part, to detect occult tumor in patients with recurrent colorectal cancer. Unfortunately, however, patients are sometimes found to have unresectable peritoneal metastasis. For these patients, intraperitoneal hyperthermic perfusion (IPHP) with mitomycin C (MMC) was used as a novel treatment method. Thirty-six intraperitoneal hyperthermic perfusions with MMC were given over the course of several studies. A preliminary study delineated two groups as possible candidates for this treatment: patients with pseudomyxoma peritonei and patients with peritoneal metastasis < 0.5 cm. Intraperitoneal hyperthermic perfusion (IPHP) was conducted for 1 hour after achieving an abdominal temperature of 41 degrees C. A dose of 30 mg MMC in 31 Plasmalyte was injected followed by a second 30 mg dose given at 30 minutes. Plasma pharmacokinetics of IPHP with MMC indicate an advantage in the range of 100-fold enhancement of exposure compared with delivery in plasma. The method was found to be safe when flow was observed and dosage decisions were made during perfusion according to flow. A clinical study group consisting of 15 patients underwent cytoreductive surgery followed by IPHP. The majority of them had either gastrointestinal or urologic anastomoses. There were no complications. In every patient the CEA level decreased after surgery and IPHP, with a median response of 6 months. RIGS technology aided in the selection of IPHP as a treatment choice by demonstrating the presence of an occult tumor burden in those patients whose traditional explorations were deceiving. This chapter includes technical details and suggestions for improving and modifying the use of IPHP.