INTRAPERITONEAL EXFOLIATED CANCER-CELLS IN PATIENTS WITH COLORECTAL-CANCER

PURPOSE: The aims of this study were to e-valuate potential predictors of exfoliated free cancer cells in the peritoneal cavity and to asses s intraoperative peritoneal lavage cytology as a prognostic indicator in patients with colorectal cancer. METHODS: From 1985 to 1987, intrao perative peritoneal lavage cytology was performed in 140 patients with colorectal cancer. Among them, 88 patients underwent curative resecti on and 52 patients had noncurative surgery. Cytology was examined mice , i.e., immediately after opening the peritoneal cavity (precytology) and just before closing the abdomen (postcytology). One hundred millil iters of saline was poured into the peritoneal cavity and it was retri eved by suction after irrigation. Cytologic examination was performed after staining with Papanicolaou, Giemsa, periodic acid-Schiff, and Al cian blue stains. RESULTS: Among the 140 patients examined, the incide nce of positive cytology in the prelavage was 15 percent, and that in the postlavage was 9 percent, although it was 16 percent in either lav age. Among patients with curative resection, 10 percent had positive c ytology. Seven characteristics were identified as features of tumors w hich are prone to exfoliate cells into the peritoneal cavity: 1) macro scopic peritoneal dissemination, 2) liver metastasis, 3) more than 20 mi of ascites, 4) ulcerated tumors without definite borders, 5) invasi on of the serosal surface or beyond, 6) semiannular or annular shape, and 7) moderate or marked lymphatic invasion. In patients undergoing c urative surgery, among these features, circumferential involvement was the only one correlated closely with positive cytology (P < 0.02). Po sitive cytology was associated with a worse outcome. In patients who w ere resected curatively, the postcytology had a stronger influence on local recurrence than the precytology; the local recurrence rate in pa tients with positive postcytology was higher than in those with negati ve postcytology, regardless of the precytology. All patients with canc er cells in the peritoneal cavity at the end of surgery had recurrence . CONCLUSIONS: Seven characteristics were identified as risk factors f or exfoliation of cancer cells into the peritoneal cavity in patients with colorectal cancer. These findings may be helpful for the choice o f laparoscopic surgery in this era of increasing port-site metastases after laparoscopic procedure. The results of peritoneal lavage cytolog y at the end of surgery were correlated with the long-term postoperati ve outcome of colorectal cancer. Thus, meticulous follow-up and possib ly adjuvant chemotherapy may be beneficial for patients with free canc er cells in lavage fluid, even after curative surgery.