Cytohistologic assessment of antitumor effects of intraperitoneal hyperthermic perfusion with mitomycin C for patients with gastric cancer with peritoneal metastasis.

For 15 patients with refractory gastric cancer and peritoneal metastasis, intraperitoneal hyperthermic perfusion (IPHP) using mitomycin C combined with extensive surgery was prescribed. The antitumor effects were assessed cytohistologically in pre-IPHP and post-IPHP specimens of the abdominal effusion and peritoneal tissue. Gastric cancer cells in the abdominal effusion and/or lavage vanished from post-IPHP peritoneal exudate obtained from the pouch of Douglas. Peritoneal tissues from nine patients were harvested just after the IPHP treatment. All the nuclei of cancer cells were pyknotic in three of nine patients, and two of these three patients are alive with no local recurrence; one patient died of hepatic metastasis. In the remaining six patients, four with preoperative ascitic effusion and positive post-IPHP histologic findings died of peritoneal, intraabdominal, and pericardial metastases. The other two had some residual microscopic foci in the subperitoneal deep layer; one patient died of pleural recurrence, and the other is alive with no evidence of recurrence 42 months after the IPHP. Among the other six patients, whose post-IPHP peritoneal tissues were not available because of disappearance of disseminating foci as a result of the IPHP, two are living with no recurrence and, of the remaining four patients, three died of hepatic and intraabdominal metastases and the other one died of other causes. The histologic findings are suggestive of the following: (1) uniform heat and drug distribution in the abdominal cavity with IPHP treatment, except for an area adjacent to the inflow point of the perfusate; and (2) limited penetration of heat and drug through the subperitoneal layer. Thus, IPHP treatment results in complete destruction of cancer cells in the abdominal effusion and on and just beneath the peritoneum.