Peripheral lymphocyte count as an indicator of radiotherapy effectiveness in hypopharyngeal squamous cell carcinoma

Abstract Objectives To explore the predictive significance of baseline absolute peripheral lymphocyte counts (ALC) in the effectiveness of radiation in hypopharyngeal squamous cell carcinoma (HPSCC) patients. Design, Setting, and Participants A retrospective study of pathologically confirmed HPSCC patients who had definitive radiation between January 2020 and January 2022 at Fudan University Eye and ENT Hospital. The routine blood results of patients were obtained to determine if the baseline ALC was connected with the response to radiation. The receiver operator characteristic (ROC) curve and LASSO‐based Cox regression were employed to assess the predictive value of ALC for the efficacy of radiotherapy (RT). Main Outcome Measures and Results RT induced a considerable drop in ALC and the level of ALC did not revert to the baseline values 1 year after radiation. The baseline level of ALC was higher in patients who met complete response after RT. The baseline ALC and monocyte counts demonstrated the predictive value of radiation effectiveness and ALC was an independent predictor. Conclusion In HPSCC, lymphocytes were sensitive to radiation and reduced significantly during RT. The baseline ALC might be regarded as a predictive indicator of the effectiveness of RT.