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

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.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.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).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).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.