Impact of thymus dose-volume parameters on radiation-induced lymphopenia in early-stage breast cancer patients during postoperative adjuvant radiotherapy
10.3760/cma.j.cn113030-20250228-00074
- VernacularTitle:早期乳腺癌辅助放疗中胸腺辐射对淋巴细胞减少的影响
- Author:
Tong XIA
1
;
Liyan JIN
;
Pengfei XING
;
Sisi ZHENG
;
Jianjun QIAN
;
Ye TIAN
;
Shang CAI
Author Information
1. 苏州大学附属第二医院放射治疗科，苏州 215004
- Publication Type:Journal Article
- Keywords:
Breast neoplasms, early-stage;
Postoperative adjuvant radiotherapy;
Lymphopenia;
Thymus;
Dose-volume parameters
- From:
Chinese Journal of Radiation Oncology
2025;34(10):1001-1007
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the correlation between thymus dose-volume parameters and lymphopenia in patients with early-stage breast cancer (BC) receiving adjuvant radiotherapy (RT).Methods:Medical records of 54 patients with early-stage BC who received postoperative adjuvant RT in the Second Affiliated Hospital of Soochow University from January to December 2019 were retrospectively analyzed. Absolute lymphocyte counts (ALC) were collected at 1 month before (baseline) and weekly during RT. Lymphopenia was graded based according to the common terminology criteria for adverse events version 5.0 and nadir/baseline ALC was calculated. The thymus was delineated according to anatomical boundaries in the original RT planning system. Dosimetric parameters were obtained from the dose volume histograms. Stepwise multiple linear regression analysis was used to explore the factors associated with nadir/baseline ALC. The cutoff values of dosimetric parameters for predicting ≥grade 3 lymphopenia were obtained using the receiver operating characteristic (ROC) curve.Results:The proportion of 54 patients experiencing ≥ grade 3 lymphopenia was 38.9%. The median value of thymus volume, mean dose, V 5 Gy, V 10 Gy were 14.02 cm 3, 4.95 Gy, 36.18%, and 6.61%, respectively. Stepwise multiple linear regression analysis revealed that baseline ALC ( P=0.005), quadrant location ( P=0.005) and mean thymus dose ( P<0.001) were significantly associated with nadir/baseline ALC. ROC curve analysis indicated that the cutoff values of thymus mean dose, V 5 Gy and V 10 Gy for predicting ≥ grade 3 lymphopenia were 6.12 Gy, 35.2%, and 7.4%, respectively. Conclusions:Lymphopenia in early-stage BC patients is significantly correlated with high dosimetric parameters of the thymus during postoperative adjuvant RT. Thymus may be considered as an organ at risk during RT.
