Clinical Significance of Serum Cytokeratin 19 Fragment in the Prediction of Chemotherapy Efficacy and Prognosis in Patients with Advanced Non-small Cell Lung Cancer

Background and objective RECIST (Response Evaluation Criteria in Solid Tumors) criteria could not be used to detect viable tumor tissue and is not an accurate tool for evaluation of objective response (OR) in non-small cell lung cancer (NSCLC) patients without measurable lesions. The aim of this study is to detect the pre- and post-chemotherapy serum cytokeratin 19 fragment (CYFRA21-1) expression levels in advanced NSCLC patients to evaluate the clinical value of CYFRA21-1 in the prediction of chemotherapy response and prognosis in NSCLC patients. Methods A automatic electrochemiluminescence immunoassay analyzer was applied to detect the pre- and post-chemotherapy serum CYFRA21-1 expression levels in 112 cases of initial treatment patients with NSCLC. Application of receiver operating characteristics curve (ROC) curve in evaluation the significance of serum CYFRA21-1 response in the diagnosis of OR and its correlation with prognosis. Results After 2 cycles of platinum-based combined chemotherapy, post-chemotherapy serum CYFRA21-1 significantly decreased compared with baseline levels. 80 patients were evaluable for radiological and serological efficacy, and 26.3% (21/80) patients achieved radiological OR. The decrease ratio of post-chemotherapy serum CYFRA21-1 with CYFRA21-1 response was 40.0% (32/80). There was significant correlation between serum CYFRA21-1 response and OR (P < 0.001). The median survival time of all patients was 9.9 months; the survival of patients with CYFRA21-1 response were significantly longer than those without CYFRA21-1 responders (12.3 months vs 8.9 months, P < 0.001). Univariate survival analysis showed that PS score, OR, baseline serum CYFRA21-1 level and CYFRA21-1 response were important prognostic factors. Cox multivariate survival analysis confirmed that only the PS score, serum CYFRA21-1 baseline levels and CYFRA21-1 response were independent prognostic factors of NSCLC patients; OR was not an independent prognostic factor. Conclusion Serum CYFRA21-1 level can be sensitive to reflect changes in tumor volume, which may be a reliable substitution index for evaluation the chemotherapy efficacy in advanced NSCLC patients and a good indicator for prediction the prognosis of survival.