The impact of different modalities of chemoradiation therapy and chemotherapy regimens on lymphopenia in patients with locally advanced non-small cell lung cancer.

Background: Chemotherapy and radiotherapy (RT) would induce lymphopenia, leading to a poor prognosis. This study investigated whether chemotherapy increased lymphopenia during RT and explored the impacts of different chemotherapy regimens on the lymphocyte counts of patients receiving RT.

Methods: Clinical parameters and lymphocyte data were collected from 215 patients with locally advanced non-small cell lung cancer (LA-NSCLC). Severe lymphopenia (SRL) was defined as an absolute lymphocyte count (ALC) of ≤0.2×10 cells/μL. Patient overall survival (OS) was analyzed using the Kaplan-Meier method. The predictors of SRL were extracted using univariate and multivariate regression analyses with backward likelihood ratio elimination.

Results: Compared with patients without SRL, patients with SRL with LA-NSCLC showed a poorer prognosis in terms of OS (P=0.003). Of the 215 patients, 130 underwent concurrent chemoradiotherapy (CCRT) and 85 underwent sequential chemoradiotherapy (SCRT). The OS was better in patients without SRL (in the CCRT group, P=0.01 and in the SCRT group, P=0.08). The mean ALCs for CCRT and SCRT did not differ significantly (P=0.27). The minimum ALC of CCRT was significantly lower than that of SCRT (P<0.0001). CCRT was a predictor of SRL (P=0.008). However, multivariate analysis showed that the different chemotherapy regimens were not predictors of SRL (all P>0.1).

Conclusions: In LA-NSCLC, the outcomes of patients with SRL were poorer than those without SRL. RT and chemotherapy were the main factors affecting SRL development, while different chemotherapy regimens were not significantly associated with lymphocyte counts in LA-NSCLC.