Intraoperative and early postoperative chemotherapy into the abdominal cavity using gemcitabine may prevent postoperative occurence of peritoneal carcinomatosis.

BACKGROUND AND OBJECTIVES

Malignant tumors of various abdominal organs are blamed to be the cause of death in approximately 40% of cases per year in Western Europe. At the time of death, about half of them show peritoneal carcinomatosis which is considered an unfavorable prognostic factor. In case of peritoneal carcinomatosis, there is no curative treatment available for any of the tumors in the abdominal cavity. The aim of this experimental study was to evaluate the preventive potential of intra-operative or early postoperative local administration of gemcitabine into the abdominal cavity against peritoneal carcinomatosis.

METHODS

Peritoneal carcinomatosis was induced in male WAG rats (n = 18) by transfer of 5 x 10(6) cells of the adenocarcinoma cell line CC-531 via minilaparotomy carried out in all rats under general anesthesia. Thirty days after cell transfer, rats were sacrificed and peritoneal carcinomatosis was confirmed using histologic investigation in specimens obtained from the peritoneal site. Extension of this carcinomatosis was quantified by (i) counting tumor nodes per square centimeter (mean of several counts) and (ii) determining tumor weight (weight of the greater omentum plus the resected mesentery). Rats were subdivided into three groups (n = 6 per group): group 1 (controls); group 2, simultaneously with tumor cell transfer 24 mg/kg of gemcitabine were administered into the abdominal cavity; group 3, postoperative intraperitoneal irrigation with 24 mg/kg of gemcitabine was achieved via a previously implanted port-a-cath on days(d) 15, 21, and 27.

RESULTS

On the 30th postoperative day, all six animals of the control group showed extensive tumor growth at the peritoneum and greater omentum, indicating carcinomatosis. In contrast, none of the rats of group 2 revealed any traces of intraperitoneal tumor growth. While all rats of group 3 demonstrated intraperitoneal tumor growth, but early postoperative treatment with gemcitabine, however, resulted in a significant reduction of the number of tumor nodes and tumor weight in comparison with group 1 (controls).

CONCLUSIONS

Immediate, i.e., simultaneous intraoperative application of a cytostatic agent such as gemcitabine into the abdominal cavity may completely prevent the generation of peritoneal carcinomatosis from occuring tumor cells, whereas early postoperative locoregional chemotherapy into the abdominal cavity can only reduce the severity of the peritoneal carcinomatosis.