The patient greater than or equal to 30 kg must have histologically proven peritoneal carcinomatosis from one of the following histologies: 1) primary peritoneal mesothelioma; 2) low grade mucinous adenocarcinoma (including low grade mucinous neoplasms of borderline malignant potential); 3) adenocarcinoma of gastrointestinal tract origin (other than low grade mucinous, excluding pancreatic cancer), with disease confined to the peritoneal cavity. Patients may not have had treatment for their disease within the previous 30 days and have recovered from all toxicity. Patients must meet certain safety laboratory criteria and may not have major medical disorders that would place them at unacceptable risk for a major surgical procedure. Patients may not have received prior intraperitoneal platinum therapy.