Radiation-Induced Lymphopenia is Associated with Worse Survival in Patients Treated with Radiation Therapy for Cervical Cancer

To evaluate the prognostic impact of radiation therapy (RT)-induced lymphopenia on survival outcomes in patients with cervical cancer treated with RT. Study design: We retrospectively reviewed 215 patients with histologically confirmed cervical cancer who received RT with concurrent chemotherapy between January 2001 and December 2017. The severity of lymphopenia was quantified using the ratio of pretreatment absolute lymphocyte count (ALC) to nadir ALC during RT (∆ALC/preALC). The optimal cutoff of ∆ALC/preALC for survival analysis was determined to be 0.88. Survival outcomes were assessed using Kaplan-Meier analysis and Cox proportional hazard models. Results: The median follow-up duration was 61.0 months. Patients with severe lymphopenia (∆ALC/preALC > 0.88) had significantly worse disease-free survival (DFS) and overall survival (OS). On multivariable analysis, ∆ALC/preALC > 0.88 remained an independent prognostic factor for both DFS (HR 2.18, p = 0.011) and OS (HR 2.54, p = 0.009). The impact of lymphopenia on survival was most pronounced in patients receiving extended field RT compared to whole pelvis RT (mean ∆ALC/preALC: 0.85 vs. 0.77, p < 0.001). Subgroup analysis showed lymphopenia was a significant prognostic factor only in the extended field RT group. Conclusion: RT-induced lymphopenia is associated with inferior survival in cervical cancer patients, particularly those receiving extended field RT. Strategies to mitigate lymphopenia, such as minimizing RT fields or using advanced bone marrow-sparing techniques, may improve patient outcomes.