Influencing factors of lymphopenia after conventional fractionated whole-breast radiotherapy following breast-conserving surgery for early breast cancer: a retrospective study

Objective: To explore the risk factors for grade 2 or higher lymphocytopenia during whole-breast radiotherapy after breast-conserving surgery for breast cancer. Methods: A total of 112 patients who underwent whole-breast radiotherapy after breast-conserving surgery for breast cancer in our department from June 2019 to June 2024 were selected and divided into the no/mild lymphopenia group (no or grade 1 lymphocytopenia, 48 cases) and moderate/severe lymphopenia group (grade 2 or higher lymphocytopenia, 64 cases). Univariate and multivariate logistic regression analyses were performed on the clinical data and dosimetric parameters of the two groups to identify the independent risk factors for grade 2 or higher lymphocytopenia. The predictive efficacy of the risk factors was established using the receiver operating characteristic (ROC) curve. Results: /L and 2.85 Gy, respectively. The area under the curve (AUC) values were 0.787 and 0.7, with corresponding sensitivities of 82.8% and 75.6%, and specificities of 70.4% and 76.7%, respectively. Conclusion: /L before chemotherapy and D80 of the sternum >2.85 Gy are independent risk factors for grade 2 or higher lymphocytopenia during whole-breast radiotherapy after breast-conserving surgery for breast cancer.