Diagnostic laparoscopy, serum CA125, and peritoneal metastasis in gastric cancer

Background and Study Aims: Peritoneal metastasis is a crucial factor for the prognosis in gastric cancer, but its diagnosis is difficult before laparotomy. We report on the utility of laparoscopy and its indications in the detection of peritoneal metastasis in gastric cancer. Patients and Methods: A total of 39 patients with gastric cancer underwent laparoscopy and peritoneal cytology investigation in our department, between April 1992 and April 2000. Laparoscopic diagnosis for peritoneal metastasis (LP-P) was determined through macroscopic, pathological and cytological diagnoses. All the patients underwent diagnostic imaging with computed tomography (CT) and ultrasound before laparoscopy. Carcinoembryonic antigen, carbohydrate antigen (CA) 19-9, and CA125 levels in serum and peritoneal fluid were measured using enzyme immunoassay. Results: Laparoscopic diagnosis for peritoneal metastasis gave negative results in 21 patients and positive results in 18. All the patients with negative LP-P findings underwent surgery; 18 of the 21 patients showed no peritoneal metastasis, but three were diagnosed as having peritoneal metastasis, one at the pouch of Douglas and two at the mesentery. The diagnosis of all the patients with positive LP-P findings was finally confirmed as correct. The specificity, sensitivity, and accuracy of laparoscopy for peritoneal metastasis were 100% (18/18, 95% Cl 0.82-1), 86% (18/21, 95% CI 0.64 - 0.97), and 92 % (36/39, 95 % CI 0.79 - 0.98), respectively. The specificity, sensitivity, and accuracy of diagnostic imaging for peritoneal metastasis were 100 % (18/18, 95 % CI 0.82-1),38% (8/21, 95% CI 0.18-0.62), and 67% (26/39, 95% CI 0.50-0.81), respectively. All of the 11 patients showing high levels of serum CA125 (equal to or more than 35 U/ml) had peritoneal metastasis whereas 17 of the 26 patients with low levels of serum CA125 (less than 35 U/ml) did not (P < 0.001). Conclusions: The sensitivity of laparoscopy for peritoneal metastasis was much higher than that of diagnostic imaging. Laparoscopy and serum CA125 level both predicted peritoneal metastasis, but the degree, volume, or distribution of peritoneal metastasis was disclosed only by laparoscopy. Laparoscopy is a useful way of detecting peritoneal metastasis in gastric cancer, and patients with an elevated level of serum CA125 are the best candidates for laparoscopy.