Department of Radiation Oncology, Stony Brook University, Stony Brook, NY.
Renaissance School of Medicine, Stony Brook, New York.
Int J Radiat Oncol Biol Phys. 2024 Feb 1;118(2):436-442. doi: 10.1016/j.ijrobp.2023.08.064. Epub 2023 Oct 2.
Surgery is the backbone of breast cancer (BC) treatment. For patients who cannot undergo surgery, improving local control (LC) of the primary tumor is paramount. To that end, this study explored the role of stereotactic body radiation therapy (SBRT).
Between 2015 and 2022, 21 nonsurgical candidates (10 metastatic, 11 stage IA-IIIC) received 23 SBRT courses to primary BC. Seven were analyzed retrospectively; 15 are currently enrolled in a prospective study. SBRT (40 Gy/5 fractions) was delivered every other day. Follow-up imaging was reviewed. Acute (≤3 months) and late toxicities were evaluated using Common Terminology Criteria for Adverse Events, version 5. LC and overall survival (OS) were estimated using Kaplan-Meier curves.
Median age was 78.4 years (45.9-97.3). Median follow-up was 14.7 months (3.3-70.3). Median pre-SBRT index lesion size was 3.1 cm (0.5-14.5) and planning treatment volume was 32.4 cc (11.5-522.4). Initial posttreatment imaging performed at a median 4.0 months (0.6-11.9) post-SBRT demonstrated median decrease in index lesion size of 20.8% (0%-100%); SUV reduction of 65.2% (20.8%-100%). Second follow-up scans at a median 7.8 months post-SBRT showed 62% (0%-100%) and 88% (33.3%-100%) median reduction in tumor size and SUV, respectively, compared with pre-SBRT values. The estimated LC rate was 100% at 6 months and 93.3% at 12, 24, and 36 months. Local progression occurred in 1 case 9.5 months after SBRT, after an initial response. Regional progression occurred in 4 cases (17.4%) at a median 18.6 months (5.2-22.7) post-SBRT. Six patients (35.3%) developed distant progression at a median 2.7 months (0.9-16.2). The estimated OS was 85.7% at 6 months, 69.6% at 12 months, and 63.8% at 24 and 36 months. The rates of acute toxicity were G1: 47.8%, G2: 4.3%, G3: 8.7%, and G4: 0%.
Definitive SBRT for primary BC resulted in good LC in nonsurgical patients and was well-tolerated. Considering the pattern of progression, additional approaches to improve regional/distant control should be investigated.
手术是乳腺癌（BC）治疗的基础。对于不能接受手术的患者，提高原发性肿瘤的局部控制（LC）至关重要。为此，本研究探讨了立体定向体部放射治疗（SBRT）的作用。
在 2015 年至 2022 年期间，21 名非手术候选者（10 名转移性，11 名 IA-IIIC 期）接受了 23 次原发性 BC 的 SBRT 治疗。其中 7 例进行了回顾性分析；15 例目前正在前瞻性研究中。SBRT（40 Gy/5 次分割）每隔一天进行一次。随访影像学检查。使用常见不良事件术语标准，第 5 版评估急性（≤3 个月）和迟发性毒性。使用 Kaplan-Meier 曲线估计 LC 和总生存（OS）。
中位年龄为 78.4 岁（45.9-97.3）。中位随访时间为 14.7 个月（3.3-70.3）。中位 SBRT 前病灶大小为 3.1 cm（0.5-14.5），计划治疗体积为 32.4 cc（11.5-522.4）。SBRT 后中位 4.0 个月（0.6-11.9）进行初始治疗后影像学检查，显示病灶大小中位下降 20.8%（0%-100%）；SUV 降低 65.2%（20.8%-100%）。SBRT 后中位 7.8 个月的第二次随访扫描显示，与 SBRT 前相比，肿瘤大小和 SUV 分别有 62%（0%-100%）和 88%（33.3%-100%）的中位下降。6 个月时的估计 LC 率为 100%，12、24 和 36 个月时分别为 93.3%。SBRT 后 9.5 个月，1 例患者出现初始反应后局部进展。SBRT 后中位 18.6 个月（5.2-22.7），4 例（17.4%）出现区域进展。SBRT 后中位 2.7 个月（0.9-16.2）时，6 例（35.3%）发生远处进展。6 个月时的估计 OS 为 85.7%，12 个月时为 69.6%，24 和 36 个月时分别为 63.8%。急性毒性发生率为 G1：47.8%，G2：4.3%，G3：8.7%，G4：0%。
非手术患者的原发性 BC 确定性 SBRT 治疗可获得良好的 LC，且耐受性良好。考虑到进展模式，应研究改善区域/远处控制的其他方法。
