Prognostic stratification of pathological node-negative lung adenocarcinoma by carcinoembryonic antigen level

Carcinoembryonic antigen (CEA) is a well-known tumour marker for lung adenocarcinoma (AC). This study was conducted to evaluate the clinical characteristics and prognosis of patients with pathological node-negative lung AC who have a high preoperative level of CEA.

Among 2124 patients with lung AC between 2003 and 2016, 858 patients were enrolled. CEA levels were dichotomized as normal (≤5 ng/ml) or high (>5 ng/ml). According to the levels of CEA between 6 and 12 months after surgery, patients were divided into a normalized and a remained-high group. Propensity score matching was used to compare 80 patients without adjuvant chemotherapy (ACT) with 39 patients with ACT. Kaplan-Meier survival analysis with the log-rank test and Cox proportional hazards regression analysis were performed for recurrence-free survival (RFS) and overall survival (OS).

The multivariable analysis showed that high maximum standardized uptake value and T2 stage were more common in patients with high levels of CEA. The median follow-up period was 52.8 months (range 6-169 months). The 5-year RFS and OS rates were 89.3% and 68.9% and 92.8% and 77.2% in normal patients and patients with high levels of CEA, respectively, with a statistically significant difference. The 5-year RFS was 79.4% and 39.2% in the normalized and remained-high groups after surgery, respectively (P = 0.011). The 5-year RFS and OS rates were 68.9% and 62.2% and 80.1% and 82.9% in patients without and with ACT, respectively. After propensity score matching, RFS was not significantly different between patients without and with ACT (P = 0.500); however, OS was significantly better in patients with ACT than in those without ACT (P = 0.001).

The clinicopathological characteristics, RFS and OS of patients with lung AC might be well discriminated by preoperative CEA levels. In patients with node-negative disease and high CEA levels, those with normalized CEA levels had a significantly better prognosis than those with persistently high CEA levels.