Objective: To investigate the correlation of CD4+CD29+ regulatory T cells (Treg) with tumor recurrence and survival time in patients with non-small cell lung cancer (NSCLC).
Methods: Fifty-nine patients with NSCLC treated with radical surgery were followed up for 5 years. Blood Treg cells were examined during the follow-up using flow cytometry (FCM). The sensitivity and specificity of Treg cells to predict recurrence of NSCLC were analyzed using receiver-operating characteristic (ROC) curve and compared with those of carcinoembryonic antigen (CEA) and cytokeratin21-1 (Cyfra21-1). The influences of gender, age, occupation and radiotherapy on survival time of the patients were analyzed with Kaplan-Meier method.
Results: Among the 59 patients, the shortest survival time was 23 months while the longest time was over 67 months. Nineteen patients had NSCLC recurrence, and 17 (28.81%) of them died of metastasis during the follow-up. The frequencies of blood Treg cells in patients who did not receive radiotherapy and in patients with tumor recurrence were significantly higher than those in patients receiving radiotherapy and in patients free of recurrence (P=0.000). ROC curves showed that the area under curve (AUC) lowered in the order of Treg cells, Cyfra21-1, CEA (P=0.002, 0.006 and 0.013, respectively) with 95% confidence interval (CI) of 0.649-0.981, 0.621-0.936 and 0.584-0.944, respectively. At the cut-off value of 7.53%, the sensitivity and specificity of Treg cells to predict NSCLC recurrence was 91.42% and 87.59%, respectively. The five-year survival rate of the 59 patients was 71.18% (42/59), and Kaplan-Meier analysis revealed a longer survival time in female patients (P=0.038), in patients below 50 years of age (P=0.013), in patients not engaging in mental work (P=0.029), and in patients receiving radiotherapy (P=0.003).
Conclusion: Treg cells has a better efficiency than Cyfra21-1 and CEA to predict tumor recurrence in patients with NSCLC following radical surgery. The male gender, an age beyond 50 years, an occupation of mental work, and failure to receive radiotherapy are all risk factors for recurrence of NSCLC.