Elevation of Serum Carcinoembryonic Antigen Concentration Caused by Everolimus-Induced Lung Injury: A Case Report

Serum carcinoembryonic antigen elevation in benign lung diseases

Carcinoembryonic antigen (CEA) is not only used to aid the diagnosis of lung cancer, but also help monitor recurrence and determine the prognosis of lung cancer as well as evaluate the therapeutic efficacy for lung cancer. However, studies have also shown that CEA is present at low levels in the serum of patients with benign lung diseases (BLD), which will interfere with the accurate judgment of the disease. Due to difference in sample size, detection methods, cutoff values and sources of BLD, the positive rate of CEA in BLD is different with different literature. Therefore, it is necessary to define CEA levels in patients of different BLD in a large sample study. 4796 patients with BLD were included in this study. The results showed that the CEA levels of 3.1% (149/4796) patients with BLD were elevated, with three cases exceeds 20 ng/mL (0.06%, 3/4796). The results from the literature showed that BLD had a mean positive rate of 5.99% (53/885) and only two cases had CEA above 20 ng/mL. The CEA elevations mainly distributed in chronic obstructive pulmonary disease (COPD), pneumonitis and interstitial lung disease and significantly correlated with age of patients (OR 2.69, 95% CI 1.94–3.73, p < 0.001). Pulmonary tuberculosis (7/1311, 0.53%) had the lowest positive rate of CEA elevations while pulmonary alveolar proteinosis (6/27, 22.22%) had the highest positive rate. The majority of patients with abnormally elevated CEA levels had multiple underlying diseases, mainly diseases of the circulatory system (42.28% [63/149]), endocrine diseases (26.85% [40/149]), and respiratory or heart failure (24.16% [36/149]. In endocrine diseases, 87.5% (35/40) of patients had diabetes. In conclusion, CEA is present at a low positive rate in the serum of patients with BLD, but few exceed 20 ng/mL. For lung disease patients, if CEA levels rise, we should carry out comprehensive analysis of types of lung diseases, age of patients, and comorbid diseases.

Association Between Pretransplant Serum Carcinoembryonic Antigen Levels and Immunohistochemical Staining of Explanted Native Lungs in Patients Who Underwent Lung Transplantation

Some patients show high serum carcinoembryonic antigen (CEA) levels in the evaluation of candidate patients for lung transplantation, which might be a challenge because high serum CEA potentially implies an existence of malignancy. For further understanding of the true meaning of high serum CEA levels in lung transplantation, we retrospectively investigated the relationship between serum CEA and clinical data. We also performed immunohistochemical analysis of explanted native lungs and evaluated its relationship with serum CEA levels. Retrospective chart review was performed in consecutive patients who underwent lung transplantation with measurement of serum CEA before and after transplantation at our institution between August 2008 and June 2017. Histopathological analysis was also performed in the same cohort of patients. Survival outcomes and pathohistological findings were compared between the high serum CEA and the normal CEA group, adjusting for potential confounding factors. One hundred and fifteen patients were eligible for analysis. High serum CEA levels before lung transplantation in most cases were decreased after the transplantation (35/39, 90%, P < 0.001). Preoperative serum CEA levels were not associated with postoperative survival. The percentage of CEA-positive alveolar cells was significantly higher in the high serum CEA group (P < 0.0001). After adjusting for potential confounding factors, there was a significant difference between the high serum CEA group and normal serum CEA group (CEA-positive alveolar cells; P = 0.002). High serum CEA levels before lung transplantation might derive from native lungs in the recipients and that they were not associated with overall survival after lung transplantation.