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

Objectives: 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.

Methods: 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).

Results: 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).

Conclusions: 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.