Carcinoembryonic antigen levels in the peritoneal cavity: useful guide to peritoneal recurrence and prognosis for gastric cancer.

At the time of laparotomy, peritoneal washings were collected from 155 gastric cancer patients and the levels of carcinoembryonic antigen (CEA) determined. The CEA levels in peritoneal washings were statistically independent of those in sera and could more reliably predict the presence of peritoneal metastasis than a cytologic study. Peritoneal recurrence was seen in 14 of 118 patients after curative operation. Of the 14 patients, 10 (71%) had elevated levels of CEA (100 ng/g protein) at surgery. Of these 10 cases, 2 of the tumors were classified as stage IB and 4 had no serosal invasion. Only one patient with peritoneal metastasis and a low CEA level was free from relapse more than 1 year after operation. Kaplan-Meier's analysis showed that a high CEA level in peritoneal washings was a predictor of poor prognosis in patients who underwent either curative or noncurative resection. A proportional hazards regression analysis showed that a high CEA level in peritoneal washings was statistically significant in terms of predicting a shorter interval until peritoneal recurrence (p = 0.0002) and for survival (p = 0.0001). The CEA level in peritoneal washings is therefore of value as an indicator of peritoneal recurrence and prognosis.