The predictive value of circulating lymphocyte subpopulation characteristics for the prognosis of patients with stage III-IV non-small cell lung cancer treated with EGFR-TKI.

[OBJECTIVE] To explore the predictive value of circulating lymphocyte subpopulation characteristics for the prognosis of stage III-IV non-small cell lung cancer (NSCLC) patients treated with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI).

[METHODS] Seventy-two cases of stage III-IV NSCLC patients treated with EGFR-TKI were retrospectively selected as study subjects. The therapeutic effects of the patients were classified into three categories: complete remission (CR) or partial remission (PR) was classified as the remission group; Stable disease (SD) was classified as the stable disease group. Progression disease (PD) is classified as the progression disease group. The clinical data (general information and circulating lymphocyte subpopulation count) of the patients with different treatment effects were compared. The patients were followed up for 5 years, and factors influencing the progression-free survival (PFS) and overall survival (OS) were screened using the COX regression model. Receiver Operating Characteristic (ROC) was plotted to get the optimal stage value of circulating lymphocytes. Changes in PFS and OS of the patients were compared using the KM survival curve.

[RESULTS] Analysis of circulating lymphocyte subsets showed that the counts of CD4 + CD45RA + CD62L + T cells in the three groups of patients presented a gradient distribution of remission group > stable disease group > progression disease group. The count of CD19 + B cells in the progression disease group (148.79 ± 39.62) was higher than that in the remission group (118.34 ± 36.71). CD4 + CD45RA + CD62L + T cells were an independent influencing factor of PFS in patients (P < 0.05). ROC curve analysis confirmed that the area under the curve (AUC) of CD4 + CD45RA + CD62L + T cell count for predicting the prognosis of NSCLC patients was 0.840 (95% CI) with a cut-off value of 126.47 and a Youden index of 0.570. The PFS of patients in the high-level group of CD4 + CD45RA + CD62L + T cells was significantly higher than that in the low-level group (P < 0.05).

[CONCLUSION] Circulating lymphocyte subsets were associated with the therapeutic effect of stage III-IV NSCLC patients treated with EGFR-TKI and can be used as a prognostic indicator of PFS in patients treated with EGFR-TKI, but a comprehensive assessment should be made in combination with clinical factors (such as stage and TKI generation).