Continuous hyperthermic peritoneal perfusion (CHPP) with a solution that contains mitomycin C (CHPP-M) has been clinically introduced as a prophylactic treatment for peritoneal recurrence of gastric cancer with serosal invasion. Two studies, each with a treated and a control group, were performed. In the historical control study the postoperative 3-year survival rate of patients (73.7%) in the treated group (n = 38) was significantly higher than the survival rate (52.7%) of those in the control group (n = 55) (P less than 0.04). In the random control study the survival rate (83%) of patients in the treated group (n = 26) was also higher than that (67.3%) of those in the control group (n = 21) in the 30 months that followed gastric surgery. However, there was no significant difference. In the historical control study with respect to the postoperative complications, anastomotic leak was observed in 8.5% of patients who were given CHPP-M and 12.8% patients who did not have CHPP-M. In the random control study anastomotic leak was observed in 3.1% of patients who had CHPP-M and 7.1% of patients who did not have CHPP-M. The incidence of adhesive ileus in patients having CHPP-M did not increase in historical or random control groups. Postoperative prolonged intestinal paresis or chemical peritonitis were not induced by CHPP-M. These results indicate that CHPP-M is a simple, safe, and readily available prophylactic therapy for peritoneal recurrence that may follow gastric cancer surgery.

We performed intraoperative peritoneal cytology in 171 gastric cancer patients undergoing curative surgery. Intraperitoneal free cancer cells were demonstrated in almost all patients in whom the area of serosal cancer invasion exceeded 15-20 cm2. In patients with both serosal cancer invasion and free cancer cells the 5-year survival rat was 13% as compared with 85% for patients who had neither, and 40% for patients who had serosal invasion but no free peritoneal cancer cells. Peritoneal metastasis was the most frequently observed recurrence pattern. Therefore, in gastric cancer patients with marked serosal invasion, intraoperative IP administration of cytocidal anticancer drugs should be considered.

Free cancer cells in the peritoneal cavity of 100 patients with gastric cancer were examined by means of Douglas lavage, and their viability was estimated by 3H-thymidine uptake with autoradiographical technic. Furthermore, the effect of mitomycin-C on the viability of free cancer cells in the peritoneal cavity was studied. The appearance of intraperitoneal free cancer cells was dependent on the degree of invasion of cancer to the gastric serosa; that is, free cancer cells were not found in cases without serosal invasion, but were found in 48% with serosal invasion. The viability of free cancer cells in the peritoneal cavity was relatively high, but could be suppressed remarkably by intraperitoneal administration of 10 mg of mitomycin-C.

The authors reviewed the medical records of 1005 patients with multiple colorectal cancers (763 synchronous and 242 metachronous) to study the number and site of the tumors, their preoperative detectability, and the results of treatment. Concurrent advanced cancers were found in 35.1%, concurrent advanced and early cancers in 59.0%, and concurrent early cancers in 5.9% of patients with synchronous malignancy. In 60.1% of these patients, the existence of multiple lesions was diagnosed preoperatively; coexisting early cancers were often overlooked. In patients with metachronous malignancy, early cancers were less frequent than in patients with synchronous malignancy. The cumulative 5‐year survival rate in curatively operated patients was 70.4% for synchronous malignancy and 66.5% for metachronous malignancy, similar to that for colon cancer in general.