Predicting Peritoneal Carcinomatosis in Locally Advanced Gastric Cancer: The Significance of Tumor Markers in the Peritoneal Washing.

Purpose: Gastric cancer is the fifth most common malignant tumor worldwide. Many attempts have been made over the years to investigate the relationship between tumor markers and the risk of recurrence. This study aims to explore the predictive value of tumor markers measured in peritoneal washing during staging laparoscopy, regarding peritoneal carcinomatosis and mortality within 1 year.

Methods: Patients with locally advanced gastric cancer, staged as at least usT2anyNM0 were submitted to staging laparoscopy in a Portuguese single center. CA 19.9, CEA, CA 125, and CA 72.4 were measured in the peritoneal washing after being harvested during staging laparoscopy.

Results: Thirty-eight patients were enrolled. After 1 year, 20 patients did not recur (52.5%), 11 (28.9%) developed carcinomatosis, and 7 (18.4%) had distant metastasis. Mortality reached 23.7% (n = 9). A statistically significant prediction of carcinomatosis was obtained for CA 125 (cutoff: 107.6 U/mL (p = 0.019)) and CEA (cutoff: 2.0 ng/mL (p = 0.020)) with 87.5% and 75% sensitivity, respectively. Prediction of mortality was significant for CA 125 (cutoff: 103.8 U/mL (p = 0.044)) and CA 125 + CEA (p = 0.030). CEA and CA 125 had NPVs of 87.9% and 93.1% regarding PC, respectively. NPVs of 88.9% and 89.2% were met concerning mortality, for the same tumor markers.

Conclusion: Performing the peritoneal liquid harvest during staging laparoscopy makes this analysis cost effective, reproducible, and does not add further morbidity. CA 125 and CEA, individually and in association, are good predictors of progression of disease and mortality within a year of staging laparoscopy in GC patients.