Combining Lactate Dehydrogenase and Fibrinogen: Potential Factors to Predict Therapeutic Efficacy and Prognosis of Patients with Small-Cell Lung Cancer

A growing interest exists in identifying reliable and low-cost biomarkers or factors that could predict the therapeutic response, prognosis, recurrence, and survival in small-cell lung cancer (SCLC). This study aimed to investigate the better predictors of chemotherapy efficacy and prognosis in patients with SCLC receiving first-line chemotherapy and radiotherapy. This study retrospectively retrieved the medical records of patients with SCLC treated with first-line platinum-based chemotherapy and radiotherapy from January 2016 to June 2019 in the First Affiliated Hospital of Nanjing Medical University. Plasma biochemical parameters, clinical features, and overall survival (OS) time were collected. The independent effects of plasma parameters on patient survival were assessed by conducting univariate and multivariate Cox regression analyses. The optimal cut-off values of independent risk factors in the ROC curve and Kaplan-Meier survival analysis were determined using MedCalc software. Statistically significant differences in lactate dehydrogenase (LDH) and fibrinogen (Fbg) were found between the complete remission + partial remission group and the non-responders, which consisted of stable-disease and progressive-disease groups, after first-line chemotherapy. Multivariate Cox regression analysis showed that LDH and Fbg were independent risk factors in predicting PFS (LDH HR: 1.013, 95% CI: 1.002-1.030, = 0.037; Fbg HR: 1.622, 95% CI: 1.094-2.526, = 0.017) and OS (LDH HR: 1.021, 95% CI: 1.008-1.034, = 0.001; Fbg HR: 2.168, 95% CI: 1.324-3.550, = 0.002). The AUC of LDH and Fbg was 0.77 and 0.745, respectively. The cut-off value of LDH and Fbg in predicting OS was 263 U/L and 4.03 g/L. When these two data were combined, the AUC reached 0.832, better than that of LDH and Fbg alone. The objective response rate (ORR) and OS were significantly different among these three different groups according to the addition of the assigned value ( < 0.05). Combined retreatment serum LDH and Fbg levels may be a better potential biomarker for predicting the clinical efficacy of chemotherapy and the prognosis of individuals with SCLC. Combining these two parameters could improve prediction efficacy.