Department of Clinical Oncology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China.
Biomedical Engineering, Shenzhen Polytechnic, Shenzhen, China.
Cancer Rep (Hoboken). 2022 Jul;5(7):e1525. doi: 10.1002/cnr2.1525. Epub 2021 Aug 14.
Lymphopenia can decrease immune function of the host and is a known risk factor for poor prognosis in malignant tumors. Radiation induced lymphopenia was common in patients with breast cancer and was also reported to have a negative effect on long-term outcome.
Lymphopenia may be associated with baseline immune status before radiotherapy (RT). This study aimed to explore the rate and risk factors of lymphopenia before start of the adjuvant RT in patients with breast cancer.
Patients with invasive breast cancer treated from March 2015 to February 2020 and with peripheral lymphocyte counts (PLC) available within 7 days from the beginning of RT were eligible for this study. Data were presented as mean and 95% confidence interval unless otherwise specified. The risk factors of low PLC before RT were identified using univariate and multivariable linear regressions.
A total of 1012 consecutive patients met the study criteria. The mean PLC before RT commencement was 1.5810 /L (95%CI: 1.55-1.6210 /L) with 15.2% (95%CI: 13.1%-17.6%) CTCAE defined lymphopenia, rendering 12.3%, 2.6%, 0.3%, and 0% for grade 1, 2, 3 and 4 respectively. Univariate and multivariable linear regression showed prior chemotherapy was the most significant risk factor (p < .001) for low PLC, while age, menopausal status and lymph node stage were not (all ps > .05). A total of 912 (90.1%, 95%CI: 88.1%-91.9%) patients had chemotherapy before adjuvant RT in this study. In patients with HR+/HER2- breast cancer, 69.0% (95%CI: 63.0%-74.5%) N0 and 98.1% (95%CI: 95.1%-99.5%) N1 had also received chemotherapy.
Patients with breast cancer might have lymphopenia from prior chemotherapy at the start of adjuvant RT which could have negative effect on long-term outcome. It is also noted that most of the patients with HR+/HER2-, early-stage breast cancer were treated with aggressive chemotherapy without knowing the risk of chemotherapy induced lymphopenia. Future study on predictive or prognostic multigene assays is warranted to avoid unnecessary chemotherapy and subsequent lymphopenia in patients with low risk breast cancer.
淋巴细胞减少可降低宿主的免疫功能，是恶性肿瘤预后不良的已知危险因素。乳腺癌患者常发生放射性淋巴细胞减少症，也有报道称其对长期预后有负面影响。
淋巴细胞减少症可能与放疗（RT）前的基线免疫状态有关。本研究旨在探讨乳腺癌患者辅助 RT 开始前淋巴细胞减少症的发生率和危险因素。
本研究纳入了 2015 年 3 月至 2020 年 2 月期间接受治疗的浸润性乳腺癌患者，且在 RT 开始后 7 天内有外周血淋巴细胞计数（PLC）数据。数据以平均值和 95%置信区间表示，除非另有说明。采用单因素和多因素线性回归分析 RT 前 PLC 较低的危险因素。
共有 1012 例连续患者符合研究标准。RT 开始前平均 PLC 为 1.5810 /L（95%CI：1.55-1.6210 /L），15.2%（95%CI：13.1%-17.6%）为 CTCAE 定义的淋巴细胞减少症，分别为 12.3%、2.6%、0.3%和 0%。单因素和多因素线性回归显示，先前的化疗是 PLC 较低的最显著危险因素（p<0.001），而年龄、绝经状态和淋巴结分期则不是（均 p>0.05）。在这项研究中，共有 912 例（90.1%，95%CI：88.1%-91.9%）患者在辅助 RT 前接受了化疗。在 HR+/HER2-乳腺癌患者中，69.0%（95%CI：63.0%-74.5%）N0 和 98.1%（95%CI：95.1%-99.5%）N1 也接受了化疗。
接受辅助 RT 的乳腺癌患者可能因先前的化疗而出现淋巴细胞减少症，这可能对长期预后产生负面影响。还值得注意的是，大多数 HR+/HER2-、早期乳腺癌患者接受了强化化疗，而没有考虑到化疗引起的淋巴细胞减少症的风险。有必要进行预测或预后多基因检测的未来研究，以避免低危乳腺癌患者不必要的化疗和随后的淋巴细胞减少症。
