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.

Carcinoembryonic antigen (CEA) levels were determined in 252 gastric cancer patients. In patients with resectable cancer, the preoperative CEA values and CEA positivity rates were 2.4 ± 1.5 ng/ml and 7.7% for stage I, 24.9 ± 72.0 ng/ml and 10.0% for stage II, 21.6 ± 84.1 ng/ml and 17.9% for stage III, and 6.3 ± 8.4 ng/ml and 27.1% for stage IV cancers, respectively. In patients with nonresectable cancers, the CEA value was 83.0 ± 235.5 ng/ml, the CEA positivity rate was 47.8%. Overall, of 252 patients with primary gastric cancer, 47(18.7%) were positive for CEA. In patients with cancer recurrence, the CEA value averaged 41.8 ± 101.8 ng/ml, the positivity rate was 63%. This rate increased as the cancer stage increased; it was highest in gastric cancer patients with liver metastasis. In 4 of 13 patients with recurrence, an elevation in CEA was observed about 4.8 months before the clinical detection of cancer recurrence. Our results suggest that in gastric cancer patients, the preoperative and periodic postoperative assay of CEA levels has predictive value in determining cancer stage, progression and recurrence.

We analyzed heating profiles from 318 hyperthermic treatments of 39 patients with recurrent or inoperable cancers of the digestive organs whose deep-seated tumors were treated by radiofrequency (RF) capacitive heating of the abdominal region, and we investigated the heating efficiency and antitumor effect of such treatment. It was apparent that heating with a mean maximum RF output of 1,000 watts (700 watts at least), repeated four times or more, was necessary for a high rate of response by the tumor. Although it was difficult to heat tumors of the bile duct/pancreas to 42 degrees C or more, there was a strong positive correlation between maximum output of RF energy and maximum temperature of tumors (r = 0.839, P less than 0.001). The antitumor effect of RF hyperthermia was augmented with increasing output of RF energy. Therefore, the maximum level of RF output may be a useful index for expressing the heating efficiency with respect to intra-abdominal deep-seated tumors.

Total-body hyperthermia (TBHT) as a treatment for cancer may lead to a reduction in the host's immunocompetence as a result of the direct effects of heat on the immune system. Thus, we studied the influences of hyperthermia in vitro on the function of peritoneal macrophages from mice. Peritoneal macrophages from C3H/HeN mice were heated in vitro for 3 hr at 37, 39, 40, 41 or 42 degrees C. After exposure to heat, the phagocytic ability of the macrophages, as well as results of the nitroblue tetrazolium (NBT) reduction test and the cytotoxicity test were examined. The changes in all these parameters showed almost the same pattern: a tendency for macrophage functions to be potentiated up to 40 degrees C, and a tendency towards inhibited functioning at temperatures above 41 degrees C. Although augmented functions of macrophages were observed after exposure to mild hyperthermia (less than 40 degrees C), the possibility of TBHT (42 degrees C)-induced inhibition of macrophage function must be further investigated in clinical trials of TBHT therapy for cancer.

Detailed histopathological examination of serial blocks and subserial sections of the entire resected esophagus in 111 patients who underwent esophagectomy for esophageal squamous cell carcinoma revealed 38 associated cancerous lesions apart from the main tumors, in 33 patients (29.7%). These associated lesions were divided into multiple primary lesions (MPLs; 27 lesions in 23 patients) and intramural metastatic lesions (IMLs; 11 lesions in 10 patients). Thirteen and fourteen MPLs were distributed on the proximal and distal sides, respectively, of the main tumor with the same mean distance of 2.6 cm. Three and 8 IMLs were located on the proximal and distal sides, respectively, with mean distances of 3.4 cm and 4.6 cm. With respect to the histological depth of cancer invasion, MPLs were all confined within the submucosal layer (superficial cancer) while IMLs varied from the submucosa to the adventitia. Histological findings indicate that MPLs may be associated with a possible increased multicentric carcinogenic potential in the non-cancerous epithelium of the esophagus of patients who have had an antecedent esophageal cancer, and that IMLs are developed by intramural lymphatic spread from the primary esophageal cancer. These results emphasize the need for careful attention to the choice of margins during the surgical resection of the esophagus.