Carcinoembryonic Antigen Messenger RNA in Pelvic Lavage Fluid Predicts Local Recurrence After Curative-Intent Resection of Rectal Cancer.

Abstract

Purpose: To evaluate whether pelvic lavage carcinoembryonic antigen (CEA) mRNA is associated with local recurrence after curative-intent resection for rectal cancer and whether it provides additional prognostic information beyond circumferential resection margin (CRM) status.

Methods: We retrospectively analyzed 178 patients who underwent curative-intent resection for primary rectal cancer. Pelvic lavage fluid was collected intraoperatively before enterotomy, and CEA mRNA levels were quantified using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). CEA mRNA positivity was defined as ≥ 0.26, and CRM positivity as ≤ 1 mm. Local recurrence was evaluated using Kaplan-Meier analysis and Cox proportional hazards modeling.

Results: During a median follow-up of 59.1 months, local recurrence occurred in 8 patients (4.5%). CEA mRNA was positive in 7 patients (3.9%), and CRM was positive in 11 patients (6.2%). Local recurrence rates were 36.4% (4/11) in CRM-positive patients and 42.9% (3/7) in CEA mRNA-positive patients. All patients who tested positive for both markers (3/3) developed local recurrence, whereas the rate was only 2.5% (4/163) among those who tested negative for both markers. In multivariable analysis, CRM positivity (HR 11.09, 95% CI 2.06-59.68, p = 0.005) and CEA mRNA positivity (HR 5.99, 95% CI 1.06-33.81, p = 0.043) remained associated with local recurrence.

Conclusions: Pelvic lavage CEA mRNA levels were associated with local recurrence beyond CRM status and may improve risk stratification. Further validation in larger multicenter cohorts is warranted.