Diagnostic Value of Tumor Markers in Peritoneal Lavage Fluid for Peritoneal Metastasis from Colorectal Cancer.

Objective: To investigate the diagnostic value of tumor markers in peritoneal lavage fluid in the diagnosis of peritoneal metastasis from colorectal cancer.

Methods: One hundred eighty-six patients with colorectal cancer and 15 patients with benign disease who underwent surgical treatment were included. The abdominal cavity and pelvis of the patients were lavaged with 200 ml of normal saline immediately after abdominal cavity incision or pneumoperitoneum establishment. Five milliliters of lavage fluid was collected for peritoneal lavage fluid tumor marker detection (pCEA, pCA19-9, pCA125 and pCA724), and another 100 ml of lavage fluid was collected for cytological examination.

Results: There were 13 patients with abdominal and pelvic nodules found intraoperatively and confirmed by postoperative pathology as peritoneal metastasis, and 24 patients were cytologically peritoneal lavage-positive, with a positivity rate of 12.9%. Peritoneal metastasis from colorectal cancer was related to tumor T stage, N stage, and serum CEA and CA19-9 elevation. Peritoneal lavage fluid tumor markers had diagnostic value for patients with and without peritoneal metastasis from colorectal cancer, and the differences were statistically significant (<0.05). Among them, pCA19-9 had the highest area under the curve (AUC), with 84.62% sensitivity and 85.19% specificity at the cutoff value. pCA19-9 had diagnostic value for peritoneal micrometastasis from colorectal cancer (<0.05), with an AUC of 0.72.

Conclusion: T stage, N stage, and serum CEA and CA19-9 elevation are associated with peritoneal metastasis from colorectal cancer. Peritoneal lavage fluid tumor markers have diagnostic value for peritoneal metastasis from colorectal cancer, among which pCA19-9 has the highest diagnostic value.