Chi Mau-Shin, Ko Hui-Ling, Yang Tsen-Long, Liu Ya-Fang, Chi Kwan-Hwa, Cheng Fiona Tsui-Fen
Department of Radiation Therapy & Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
Institute of Veterinary Clinical Science, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
Front Oncol. 2024 Oct 8;14:1411598. doi: 10.3389/fonc.2024.1411598. eCollection 2024.
Intraoperative radiation therapy (IORT) and whole breast irradiation (WBI) are both effective adjuvant radiotherapy methods for ductal carcinoma (DCIS) or early-stage breast cancer (BC) patients undergoing breast-conserving surgery (BCS). We aim to evaluate the long-term oncological efficacy and refine patient selection criteria based on our findings.
Female patients who underwent either IORT or WBI from January 2016 to December 2019, with a minimum follow-up of 12 months were collected. IORT was administered as a single fraction of 20 Gray (Gy) to the lumpectomy cavity using the Axxent electronic brachytherapy system, while WBI consisted of a standard fractionation of 50 Gy in 25 fractions, along with a reduced boost of 10 Gy. The clinicopathologic characteristics and oncological outcomes were retrospectively analyzed.
A total of 247 patients were enrolled, comprising 164 with BC and 83 with DCIS. Among them, 112 underwent IORT, and 135 received WBI after BCS. The median age was 62.2 years, with median tumor sizes of 1.5 cm for BC and 1.2 cm for DCIS. At a median follow-up of 64.6 months, IORT demonstrated 11 locoregional recurrences (LRR), 1 metastasis, and 1 death, compared to 4 LRR, 5 metastases, and 2 deaths in the WBI group. WBI yielded significantly higher locoregional control (97.0% vs. 90.2%, p = 0.033), although metastasis-free (96.3% vs. 99.1%, p = 0.166) and overall survival rates (98.4% vs. 99%, p = 0.688) did not differ. The LRR rate was significantly higher in the IORT group among the DCIS or BC patients (p = 0.043). The hazard ratio for locoregional recurrence significantly increased in estrogen-receptor-negative (ER-) patients in both univariate analysis (HR = 4.98, 95% CI = 1.76-14.09, p = 0.002) and multivariate analysis (HR = 40.88, 95% CI = 1.29-1297.84, p = 0.035). Additionally, IORT was associated with increased LRR in the multivariate analysis (HR = 4.71, 95% CI = 1.16-19.06, p = 0.030).
At a long-term follow-up, the LRR rate was higher in the BCS followed by IORT, without significant differences in metastasis-free or overall survival rates. Our data confirmed the importance of exclusion ER- patients for IORT.
术中放疗（IORT）和全乳照射（WBI）都是对接受保乳手术（BCS）的导管原位癌（DCIS）或早期乳腺癌（BC）患者有效的辅助放疗方法。我们旨在根据研究结果评估长期肿瘤学疗效并完善患者选择标准。
收集2016年1月至2019年12月期间接受IORT或WBI且随访至少12个月的女性患者。使用Axxent电子近距离放疗系统对肿块切除腔单次给予20格雷（Gy）的IORT，而WBI包括25次分割共50 Gy的标准分割，外加10 Gy的减量推量。对临床病理特征和肿瘤学结局进行回顾性分析。
共纳入247例患者，其中164例为BC，83例为DCIS。其中，112例行IORT，135例在BCS后接受WBI。中位年龄为62.2岁，BC的中位肿瘤大小为1.5 cm，DCIS为1.2 cm。中位随访64.6个月时，IORT组出现11例局部区域复发（LRR）、1例转移和1例死亡，而WBI组分别为4例LRR、5例转移和2例死亡。WBI的局部区域控制率显著更高（97.0%对90.2%，p = 0.033），尽管无转移生存率（96.3%对99.1%，p = 0.166）和总生存率（98.4%对99%，p = 0.688）无差异。DCIS或BC患者中，IORT组的LRR率显著更高（p = 0.043）。在单因素分析（HR = 4.98，95%CI = 1.76 - 14.09，p = 0.002）和多因素分析（HR = 40.88，95%CI = 1.29 - 1297.84，p = 0.035）中，雌激素受体阴性（ER-）患者局部区域复发的风险比显著增加。此外，在多因素分析中IORT与LRR增加相关（HR = 4.71，95%CI = 1.16 - 19.06，p = 0.030）。
长期随访时，BCS后行IORT的LRR率更高，无转移生存率或总生存率无显著差异。我们的数据证实了排除ER-患者接受IORT的重要性。
