Treatment-related Lymphopenia in Patients With Stage III Non-Small-Cell Lung Cancer

Background: This study sought to estimate the severity, etiology, and clinical importance of treatment-related lymphopenia in patients with stage III non-small-cell lung cancer. Methods: Serial lymphocyte counts and survival were analyzed retrospectively in 47 patients accounting for known prognostic factors. Results: Total lymphocyte counts (TLCs) were normal before therapy and did not change following neoadjuvant chemotherapy. Following radiation, TLC fell by 67% (median 500 cells/mm(3), p <.00001). Multivariate analysis revealed an association between severe TLC and survival (HR 1.70, 95% CI: 0.8-3.6). Conclusions: Rapid and severe lymphopenia occurred in 50% of patients following radiation which was associated with reduced survival.