Diagnosis and treatment of peritoneal mesothelioma: The Washington Cancer Institute experience.

Peritoneal mesothelioma is a rare disease, but increasing in frequency. The incidence is approximately one per 1,000,000 and about one fifth to one third of all mesotheliomas are peritoneal. Because of its unusual nature, the disease has not been clearly defined either in terms of its natural history, diagnosis, or management. This article reviews a single institution's experience with 51 patients prospectively treated over the past decade with increasingly aggressive local/regional protocols. Peritoneal mesothelioma patients generally present with two types of symptoms and signs; those with abdominal pain, usually localized and related to a dominant tumor mass with little or no ascites and those without abdominal pain, but with ascites and abdominal distention. Pathologically, a positive immunostain for calretinin has markedly increased the accuracy of diagnosis. Prognosis as determined by clinical presentation, the completeness of cytoreduction, and gender (females survive longer than males) appears to be improved by the use of intraperitoneal chemotherapy. Over the past decade, the management of these patients has evolved similarly to ovarian cancer treatment and now involves cytoreductive surgery, heated intraoperative intraperitoneal chemotherapy (HIIC) with cisplatin and doxorubicin, and early postoperative intraperitoneal paclitaxel. These perioperative treatments are followed by adjuvant intraperitoneal paclitaxel and second-look cytoreduction. Prolonged disease-free survival and reduced adverse symptoms with the current management strategy are documented by a high complete response rate as assessed by a negative second-look. This multimodality treatment approach with cytoreductive surgery and intraperitoneal chemotherapy has resulted in a median survival of 50 to 60 months. Peritoneal mesothelioma is an orphan disease that is treatable with expectations for "potential" cure in a small number of patients if diagnosed and treated early with definitive local/regional treatments. A prolonged high quality of life is possible in the majority of patients.