Effects of Intraperitoneal Chemotherapy with Mitomycin C on the Prevention of Peritoneal Recurrence in Colorectal Cancer Patients with Positive Peritoneal Lavage Cytology Findings

The detection of intraperitoneal free cancer cells in colorectal cancer (CRC) patients is associated with a poorer prognosis. The aim of this study was to investigate the effects of intraperitoneal chemotherapy (IPC) with mitomycin C (MMC) on preventing peritoneal recurrence in CRC patients with positive peritoneal lavage cytology findings. A total of 52 CRC patients who had no clinically confirmed peritoneal dissemination and whose status of peritoneal lavage cytology was positive were investigated. Conventional peritoneal lavage cytology was performed. Overall, 31 of the 52 patients (59.6%) were administered IPC with MMC. Before closure of the abdomen, 4 silicon catheters were inserted into peritoneal cavity. After closure, the perfusate (diluting 20 mg MMC with 500 ml saline) was instilled from the catheter, and all catheters were clumped. All catheters were opened 1 h later. The mean follow-up period was 83.1 months. According to univariate analyses of all 52 patients and the subgroup of 36 patients with stage II or III tumors, patients with IPC had a significantly better peritoneal recurrence-free survival and cancer-specific survival than patients who did not receive IPC (P < 0.005). In multivariate analysis, IPC remained an independent prognostic factor for peritoneal recurrence-free survival in all patients. It appears that IPC with MMC is an effective treatment to prevent peritoneal recurrence and prolong the cancer-specific survival in CRC patients without peritoneal dissemination, but who have positive peritoneal lavage cytology. It is necessary to verify the effectiveness of IPC with MMC in a prospective trial.