Prognostic Value of Pretreatment Serum CA199 in Patients with Locally Advanced Rectal Cancer Treated with CRT Followed by TME with Normal Pretreatment Carcinoembryonic Antigen Levels

Abstract

Background: Elevated pretreatment carcinoembryonic antigen (CEA) levels are related to poor prognosis in patients with locally advanced rectal cancer (LARC) treated with neo-CRT followed by TME. In patients with normal pretreatment CEA levels, the prognostic significance of carbohydrate antigen 199 (CA199) is controversial. Objectives: The aim of this study was to explore the prognostic value of pretreatment serum CA199 in patients with LARC who had normal pretreatment CEA levels treated with neo-CRT followed by curative surgery. Methods: A retrospective study of 456 patients with LARC treated with neo-CRT followed by TME between January 2006 and May 2017 was performed. We employed the maximal χ² method to determine the CA199 threshold of 9.1 U/mL based on the difference in survival and divided patients into 2 groups. Group 1: patients with pretreatment s-CEA < 5 ng/mL and CA199 ≥ 9.1 U/mL. Group 2: patients with pretreatment s-CEA < 5 ng/mL and CA199 < 9.1 U/mL. Overall survival (OS) across CA199 was assessed using Cox proportional hazard regression models (PS:CEA ≥ 5 ng/mL was seen as elevated). Results: Multivariate analyses demonstrated that the following factors were significantly related to OS in patients with LARC with normal pretreatment CEA levels: ypT (odds ratio [OR] 1.863, p = 0.030), ypN (OR 1.622, p = 0.026), and pretreatment CA199 levels (OR 1.886, p = 0.048). Conclusion: Pretreatment CA199 is an independent factor for OS in patients with LARC with normal pretreatment CEA levels, which may reach the clinic to guide individualized decision-making.