接受乳腺癌区域性淋巴结分次照射治疗的患者的剂量学和毒性结果：为了最大限度地降低放射性肺炎的风险，最佳的剂量-体积限制是多少？
Dosimetry and Toxicity Outcomes in Patients Treated with Hypofractionated Regional Nodal Irradiation for Breast Cancer: What is the Best Dose-Volume Limit to Minimize Risks of Radiation Pneumonitis?
机构信息
University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
Department of Radiation Oncology, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
出版信息
Pract Radiat Oncol. 2023 Jul-Aug;13(4):291-300. doi: 10.1016/j.prro.2022.10.007. Epub 2022 Nov 1.
PURPOSE
Although published data have supported the use of hypofractionated regional nodal irradiation (HF-RNI) for breast cancer, limited dosimetric data exist to evaluate predictors of lung toxicity. The ongoing RT CHARM trial limits the percentage of ipsilateral lung volume that receives ≥18 Gy to 35 to 40%. We assessed dosimetry, toxicity, and disease outcomes in patients with breast cancer treated with HF-RNI with a particular focus on pneumonitis.
METHODS AND MATERIALS
We retrospectively reviewed all patients with breast cancer treated with HF-RNI (40-43 Gy in 15-16 fractions) after either lumpectomy or mastectomy at The University of Pittsburgh Medical Center from September 2018 to December 2021 to collect dosimetric and outcomes data. All post-radiation therapy chest computed tomography (CT) scans were manually reviewed for evidence of acute (≤6 months postradiation) or chronic (>6 months postradiation) pneumonitis.
RESULTS
One-hundred-ninety-one patients qualified with a median follow-up of 20.3 months (range, 5.1-42.2). Acute grade 1 (G1) pneumonitis was observed in 6.8% of the overall cohort (13 of 191 patients) and 39.4% of the patients (13 of 33) who received a chest CT ≤6 months postradiation therapy. Only 1 patient developed acute G2 pneumonitis. Chronic G1 pneumonitis was observed in 29.8% of the overall cohort (57 of 191 patients) and 77% of patients (57 of 74 patients) who received a chest CT >6 months postradiation therapy. No patients developed acute G3+ or chronic G2+ pneumonitis.
CONCLUSIONS
Rates of symptomatic pneumonitis were low in this cohort of patients treated with HF-RNI, even with integration of HER2/neu-directed therapy, chemotherapy, hormone therapy, and internal mammary nodal irradiation. Lung V20Gy <26% appeared safe in this cohort to limit symptomatic pneumonitis, though this is not meant to represent the safe upper limit. Given the low event rate of symptomatic pneumonitis, data from larger cohorts will be needed to assess dosimetric predictors and the safe upper limit of lung dose.
目的
虽然已有研究数据支持采用低分割区域淋巴结照射（HF-RNI）治疗乳腺癌，但目前仅有有限的剂量学数据可用于评估肺毒性的预测因素。正在进行的 RT CHARM 试验将同侧肺接受≥18 Gy 的百分比限制在 35%至 40%。我们评估了接受 HF-RNI 治疗的乳腺癌患者的剂量学、毒性和疾病结局，特别关注放射性肺炎。
方法和材料
我们回顾性分析了 2018 年 9 月至 2021 年 12 月期间在匹兹堡大学医学中心接受保乳或乳房切除术治疗的乳腺癌患者的 HF-RNI（40-43 Gy，15-16 次分割）治疗后的所有患者的剂量学和结局数据，以收集剂量学和结局数据。所有放疗后的胸部 CT 扫描均由手动审查，以评估急性（放疗后≤6 个月）或慢性（放疗后>6 个月）放射性肺炎的证据。
结果
共有 191 例患者符合条件，中位随访时间为 20.3 个月（范围为 5.1-42.2）。总的队列中观察到 6.8%（191 例患者中的 13 例）和接受放疗后≤6 个月胸部 CT 的 39.4%（33 例患者中的 13 例）的患者出现急性 G1 级肺炎。仅 1 例患者发生急性 G2 级肺炎。总的队列中观察到 29.8%（191 例患者中的 57 例）和接受放疗后>6 个月胸部 CT 的 77%（74 例患者中的 57 例）的患者出现慢性 G1 级肺炎。没有患者发生急性 G3+或慢性 G2+肺炎。
结论
在接受 HF-RNI 治疗的患者中，即使整合了曲妥珠单抗、化疗、激素治疗和内乳淋巴结照射，症状性肺炎的发生率也较低。在本队列中，V20Gy<26%的肺体积似乎是安全的，可以限制症状性肺炎，但这并不意味着是安全上限。鉴于症状性肺炎的发生率较低，需要更大的队列数据来评估剂量学预测因素和肺剂量的安全上限。
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