Changes induced by surgical and clinical factors in the pharmacology of intraperitoneal mitomycin C in 145 patients with peritoneal carcinomatosis

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy are a combined treatment modality considered for selected patients with peritoneal carcinomatosis from colorectal and appendiceal cancer. Mitomycin C is a drug often used in this clinical setting. The surgical and clinical factors that may influence the pharmacokinetics of hyperthermic intraperitoneal chemotherapy should be further elucidated. The patients included were 145 who had colorectal or appendiceal carcinomatosis resected using cytoreductive surgery prior to treatment with hyperthermic intraperitoneal chemotherapy with mitomycin C as part of a multidrug regimen. The effect of clinical and surgical factors on drug distribution after single intraperitoneal bolus administration with mitomycin C was determined. The pharmacokinetics of 145 patients treated with intraperitoneal mitomycin C showed a 27 times greater exposure to peritoneal surfaces when compared to plasma. At 90 min, 29% of the drug remained in the chemotherapy solution, 62% was retained in the body, and 9% was excreted in the urine. The extent of peritonectomy increased the clearance of mitomycin C from the peritoneal space (p = 0.051). A major resection of visceral peritoneal surface and a contracted peritoneal space reduced drug clearance. A contracted peritoneal space significantly reduced (p = 0.0001) drug concentrations in the plasma. Surgical and clinical factors may require modifications of drug dose or timing of chemotherapy administration. A large visceral resection and a contracted peritoneal space caused a reduced mitomycin C clearance. Total diffusion surface is an important determinant of mitomycin C pharmacokinetics.