THE CLINICAL AND DOSIMETRIC PREDICTORS OF RADIATION-INDUCED LYMPHOPENIA AND ITS IMPACT ON SURVIVAL IN SOLID TUMORS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Background: Radiation-induced lymphopenia (RIL) is a frequent condition occurring after radiotherapy, potentially altering treatment outcomes for cancer patients. In this systematic review and meta-analysis, we assess clinical and dosimetric predictors for severe RIL and its effect on survival for various solid cancers . Methods: A systematic review was carried out as per PRISMA guidelines. The studies published between 2020 to 2025 with RIL in solid tumors were considered. The data was extracted with respect to patient details, dosimetric criteria, incidence of RIL, and survival rates. Meta-analysis was conducted with the random effects model . Results: A total of 10 studies including 2,879 patients were selected. Severe RIL (grade 3-4) was reported to affect 16-58% of the patient series overall. In the pooled analysis, severe RIL was found to be an independent predictor of poor overall survival (HR=1.50; 95% CI: 1.29-1.75) and progression-free survival (HR=1.70; 95% CI: 1.39-2.07). Dosimetric variables used in the model were planning target volume (PTV), mean body dose, heart V5-V20, and thymus dose. Clinical variables. Conclusions: Severe RIL has been found to have significant prognostic implications in survival in cases of solid tumors. The search for dosimetric and clinical risk factors can help improve radiotherapy planning in such a way as to suppress lymphopenia as little as possible.