The Prognostic Value of EDRIC and Its Association With Radiation-Induced Lymphopenia in Patients With Esophageal Cancer Undergoing Radical Radiotherapy: A Single-Center Chinese Study.

This study aimed to evaluate the predictive value of the estimated dose of radiation to immune cells (EDRIC) in patients with esophageal cancer receiving radical radiotherapy. We retrospectively reviewed the data of patients with esophageal cancer who underwent definitive radiotherapy at our institution. The Kaplan-Meier method and log-rank test were used to assess the survival curves. Univariate and multivariate Cox regression analyses were performed to identify the prognostic factors associated with overall survival (OS) and progression-free survival (PFS). Additionally, binary logistic regression analyses were used to identify factors associated with severe lymphopenia. A total of 166 patients, with a median follow-up duration of 59 months, were evaluated. The median EDRIC was 7.23 Gy. The 1-, 3-, and 5-year OS rates were 81.9%, 49.4%, and 33.7% in the EDRIC < 7.23 Gy group, compared with 62.7%, 21.7%, and 19.3% in the EDRIC ≥ 7.23 Gy group (p < 0.001). Prognostic analysis identified Eastern Cooperative Oncology Group performance status, TNM stage, treatment, EDRIC, and lymphopenia as significant independent prognostic factors of OS (p < 0.05). Higher EDRIC, N stage, and lymphopenia were identified as independent risk factors for PFS. Logistic regression analysis indicated that treatment and EDRIC were significantly associated with severe lymphopenia (p < 0.05). EDRIC serves not only as a prognostic marker for radical radiotherapy in esophageal cancer, but also as a potential biomarker for radiation-induced lymphopenia.