Abstract
From January 2018 to May 2018, 108 patients with thoracic esophageal cancer underwent esophagectomy with two- to three-field lymph node dissection. Serum cytokeratin 19 fragment antigen 21-1 (CYFRA21-1), squamous cell carcinoma antigen, and carcinoembryonic antigen levels were detected before surgery. Preoperative serum levels of CYFRA21-1 and squamous cell carcinoma antigen were correlated closely with pN stage (P = 0.000 and P = 0.045). CYFRA21-1 and pathological T status were independent predictors of lymph node metastasis (P = 0.000). The area under the curve values of CYFRA21-1 and squamous cell carcinoma antigen for predicting lymph node metastasis were 0.731 (P =0.000) and 0.650 (P =0.007), respectively. Our study demonstrated that serum CYFRA21-1 and squamous cell carcinoma antigen levels were associated with lymph node metastasis in esophageal squamous cell carcinoma, especially in patients at the early T stage. The preoperative serum CYFRA21-1 level was an independent predictor of lymph node metastasis.
Esophageal cancer ranks seventh in terms of incidence and sixth in mortality overall in worldwide. 1 Lymph node metastasis (LNM) is an important factor affecting the prognosis of esophageal squamous cell carcinoma (ESCC). The overall 5-year survival rates decreased from 51.2% in lymph node-negative patients to 12.4% in lymph node-positive patients. 2 LNM of ESCC is initially characterized by periesophageal lymph node involvement at the site of the tumor. Then, the lymph nodes metastasize laterally along the mucosal network of the esophagus. The LNM rate increases in proportion to the invasion depth of the ESCC. 3 Even in superficial ESCCs (SESCCs) the LNM rate was 8%–26% when the tumor invaded the submucosa to a depth of 200 μm or less from the muscularis mucosa (SM1).
LNM is often detected by computed tomography, endoscopic ultrasound, and positron emission tomography. However, these methods cannot completely exclude the presence of LNM. 4 Peripheral serum tumor markers are noninvasive diagnostic tools and are clinically useful if they can help to predict metastasis. The peripheral serum tumor markers cytokeratin 19 fragment antigen 21-1 (CYFRA21-1), squamous cell carcinoma antigen (SCC-Ag), and carcinoembryonic antigen (CEA) are commonly used in the management of ESCC patients. CYFRA21-1 and SCC-Ag are sensitive biomarkers for cancer screening, particularly in squamous cell carcinoma. CEA is the most widely used tumor marker for the management of solid tumors, including esophageal carcinoma.5, 6 Although several clinical investigations have shown that CYFRA21-1, SCC-Ag, and CEA serve as diagnostic and prognostic markers in esophageal carcinoma, the correlation between biomarkers and the extent of LNM has not been well elucidated. In this study, we analyzed the predictive significance of serum CYFRA21-1, SCC-Ag, and CEA levels for LNM in patients with ESCC.
From January 2018 to May 2018, 108 patients with ESCC underwent esophagectomy. All patients were recruited from the First Affiliated Hospital of the University of Science and Technology of China (USTC) (Anhui Provincial Hospital). Patients were selected based on the following eligibility criteria: (a) tumors located in the thoracic esophagus; (b) histopathologically proven esophageal cancer; (c) esophagectomy with two- to three- field lymph node dissection performed; and (d) no known distant metastasis. Patients were excluded if they met one of the following criteria: (a) received palliative resection; (b) had less than 15 lymph nodes dissected (National Comprehensive Cancer Network (NCCN) guidelines for treatment of esophageal and esophagogastric junction cancers); or (c) received neoadjuvant therapy. Tumor node metastasis (TNM) staging was defined according to the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) TNM classification system (8th edition). 7 Serum CYFRA21-1 levels detected before surgery with an electrochemiluminescence immunoassay (Roche cobas® 8000 modular analyzer series, Germany). Serum SCC-Ag and CEA levels were detected by chemical luminescence immunoassays (Abbott Architect i2000SR, USA). The cut-off values for CYFRA21-1, CEA, and SCC-Ag levels were 3.3 ng/mL, 5 ng/mL, and 1.5 ng/mL, respectively. The study was approved by the Ethics Committee of The First Affiliated Hospital of USTC (2018-KY-22) and conforms to the provisions of in accordance with the Helsinki Declaration as revised in 2013.
Statistical analysis was performed using SPSS software, version 19 (SPSS Inc., Chicago, IL). For these analyses, the correlations between the preoperative serum levels of CYFRA21-1, SCC-Ag, and CEA, and the clinicopathological characteristics were analyzed using the Chi-squared or Mann-Whitney U tests. Logistic regression analysis was performed for all parameters that were found to be significant in the univariate analysis. To evaluate and compare the predictive performance of the serum biologic markers, we employed a receiver operating characteristic (ROC) curve. The area under the ROC curve (AUC) was used as the criterion. An AUC of 0.5 indicated no predictive ability, whereas a value of 1 represented perfect predictive ability. A larger AUC indicated better predictability. Statistical significance was set at P < 0.05 throughout the study.
The mean age of the patients was 66.39±7.35 years (range, 48–84 years). Of all patients, 75 (69.44%) underwent Ivor-Lewis thoracotomy (two-field), and 33 (30.56%) underwent a three-field thoracotomy. The distribution of pTNM stages was as follows: 42 patients with stage I-IIA ESCC (38.89%) and 66 patients with stage IIB-IVA disease (61.11%). The characteristics of the patients are shown in Table 1.
Characteristics of the ESCC patients.
CEA: carcinoembryonic antigen; ESCC: esophageal squamous cell carcinoma SCC-Ag: squamous cell carcinoma antigen; TNM: tumor node metastasis.
The relationship between clinicopathological parameters and LNM in ESCC patients is shown in Table 2. Preoperative serum levels of CYFRA21-1 and SCC-Ag were associated with LNM in the Chi-square test (CYFRA21-1 P=0.000 and SCC-Ag P=0.013), and preoperative serum levels of CEA were not associated with LNM in the Chi-square test (P=0.145). Pathological T status was associated with LNM in the Chi-square test (P=0.000). In the logistic regression analysis, levels and pathological T status were independent predictive factors for LNM (CYFRA21-1 P=0.000 and pathological T status P=0.007). To analyze preoperative serum levels of biomarkers and LNM in early and advanced T stages, patients were divided into two subgroups; namely, pTis-T2 and pT3-4. The preoperative serum levels of CYFRA21-1 were significantly associated with LNM (P=0.001) in patients with pTis-T2 ESCC. However, the preoperative serum levels of SCC-Ag were not associated with LNM in patients with pTis-T2 ESCC (SCC-Ag P=0.914). In patients with pT3-4 ESCC, preoperative serum levels of CYFRA21-1 were associated with LNM (P=0.044). However, no correlation was found for SCC-Ag levels with LNM in these patients (Table 3). Preoperative serum levels of CYFRA21-1 and SCC-Ag were correlated closely with pN stage (CYFRA21-1 P= 0.000 and SCC-Ag P= 0.045) (Table 4).
Relationship between clinicopathological parameters and LNM in ESCC patients.
CEA: carcinoembryonic antigen; ESCC: esophageal squamous cell carcinoma; LNM: lymph node metastasis; OR: odds ratio.
Correlation between biomarkers and LNM in pTis-T2 and pT3-T4 stage ESCC patients.
ESCC: esophageal squamous cell carcinoma; lymph node metastasis; SCC-Ag: squamous cell carcinoma antigen.
CYFRA21-1 level: Low (⩽3.30 ng/mL); high (>3.30 ng/mL).
SCC-Ag level: Low (⩽1.5 ng/mL); high (>1.5 ng/mL).
Correlation between biomarkers and pN in ESCC patients.
ESCC: esophageal squamous cell carcinoma; SCC-Ag: squamous cell carcinoma antigen.
CYFRA21-1 level: Low (⩽3.30 ng/mL); high (>3.30 ng/mL).
SCC-Ag level: Low (⩽1.5 ng/mL); high (>1.5 ng/mL).
Several previous studies have revealed the prognostic significance of CYFRA21-1, SCC-Ag, and CEA levels in ESCC.6, 8, 9 However, the predictive values of these serum biomarker levels for the extent of LNM in ESCC have not been well elucidated and studied. LNM is an important prognostic factor and an early event in patients with ESCC. In tumors invading the submucosa, the minimum submucosal invasion thickness in patients with LNM was 250µm. 10 Lymph node involvement occurred in 6.25% (4/64) of mucosal cancers and 29.3% (39/133) of submucosal cancers. 11 Regional lymph node recurrence frequently occurs after surgery for ESCC, and the prognosis is poor. 12 Even if the primary tumor is limited to the submucosal layer, recurrence after surgery may involve the lymph nodes. The clinical value of evaluating lymph node status is in deciding whether patients should undergo neoadjuvant therapy before esophagostomy, 9 and in detecting lymph node recurrence early.
Our findings indicate that preoperative serum CYFRA21-1 and SCC-Ag levels are closely associated with LNM in ESCC. Preoperative serum CYFRA21-1 levels were significantly associated with LNM and pN stage, and were independent predictive factors for LNM in ESCC patients. To better identify the risk of patients with early and advanced T stage ESCC, we examined CYFRA21-1 levels in the pTis-T2 group and the pT3-4 group. In the pTis-T2 group, preoperative serum CYFRA21-1 levels were significantly associated with LNM (P=0.001). In the pT3-4 group, serum CYFRA21-1 levels were also associated with LNM (P=0.044). The results showed that serum CYFRA21-1 levels could serve as precise predictors for early stage LNM. In the present study, preoperative serum SCC-Ag levels were also associated with LNM and pN stage, but were not independent predictive factors for LNM. In the early and advanced T stage groups, preoperative serum SCC-Ag levels were associated with LNM (P=0.012) in the pTis-T2 group, but similar results were not observed in patients in the pT3-4 group.
To better identify patients at high risk for LNM, we employed an ROC curve. The ROC AUC was used as the criterion. The AUC values of CYFRA21-1 and SCC-Ag for predicting LNM were 0.731 (P=0.000) and 0.650 (P=0.007). The combined AUC value of CYFRA21-1 and SCC-Ag was 0.759. Since the 95% confidence intervals in the ROC analysis are large, the AUC value of CYFRA21-1 alone and the combination value of CYFRA21-1 and SCC-Ag are almost superimposable; therefore the combined AUC value of CYFRA21-1 and SCC-Ag is probably not useful.
There were limitations in our study. First, as a retrospective single-center study, selection bias might have been underestimated. Second, the sample size was not large enough. Larger and more homogeneous studies evaluating biomarkers for ESCC should be conducted. Third, this study did not reveal the predictive significance of the serum biomarkers for LNM in patients with recurrent tumors.
In conclusion, our study demonstrated that serum CYFRA21-1 and SCC-Ag levels were associated with LNM in ESCC, especially in patients with early T stage ESCC. The preoperative serum CYFRA21-1 level was an independent predictor of LNM.
Footnotes
Authors’ note
Xiaodong Zhu is now affiliated with Wannan Medical College, P.R. China and and Lei Zuo is now affiliated with Anhui Medical University, P.R. China.
Availability of data and materials
The datasets supporting the conclusions of this article are included within the article.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Research ethics and patient consent
The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the ethics committee of the First Affiliated Hospital of the USTC (Anhui provincial hospital) (2018-KY-22).