Clinical study on splenic radiation dose constraints.

• DOI: 10.1200/jco.2025.43.16_suppl.e16138
• Publication Date: 2025-05-28T16:22:46Z
• Authors: Yifu Ma; Yuehong Kong; Jianjun Qian; Liyuan Zhang

e16138 Background: Lymphocytes, known for their high sensitivity to radiation, are vital the body's anti-tumor mechanisms. Radiation-induced lymphopenia have been linked worse prognosis across various cancer types. Despite being largest secondary lymphoid organ, spleen is not currently designated as an organ at risk in radiation therapy protocols. This study seeks provide a reference splenic dose-volume constraints clinical radiotherapy practice. Methods: To exclude influence of tumor factors on dose and given spleen's anatomical proximity target area gastric radiotherapy, we selected patients with R0 gastrectomy who underwent adjuvant radiotherapy. A retrospective group 159 locally advanced had undergone postoperative chemoradiotherapy (CRT) between Jan 2010 2020 was analyzed. Complete blood counts were collected before, during, after CRT. Logistic regression analyses used evaluate effects variables predicting grade 4 lymphopenia. Cox proportional hazard modeling Kaplan–Meier method log-rank tests analyze correlation each variable survival outcomes. Receiver Operating Characteristic (ROC) curves utilized determine ideal threshold V 5 , lymphocyte recovery index (LRI) changes ALC (ΔALC). Results: The median follow-up period 48 months. 5-year OS DFS 56.6% 40.2%, respectively. ALCs baseline (× 10 9 /L) 1.4, 0.8, 0.5, 0.4, 0.3, 0.25, 0.2 week1–6 during CRT, values decreased by 85.71% Patients (G4) poorer rate (44.9 vs. 62.9 months, P = 0.029) than those without. analysis confirmed that independent predictor G4. Further revealed limiting < 272.2cc death 60.9% ( 0.005). LRI ΔALC identified predictors DFS, Conclusions: Constraining may indirectly improve outcomes through preservation. Additionally, can function prognostic indicators undergoing Consequently, propose design treatments.