Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland.
Int J Radiat Oncol Biol Phys. 2018 Nov 15;102(4):1374-1381. doi: 10.1016/j.ijrobp.2018.05.059. Epub 2018 Jun 5.
To evaluate the mammographic sequelae of preoperative accelerated partial breast irradiation (APBI) delivered via either stereotactic radiosurgery or a conventionally fractionated regimen.
This multicenter, retrospective study evaluated surveillance mammograms from patients enrolled in 2 prospective, preoperative APBI clinical trials. At 1 site, 31 patients with cT1N0 invasive carcinomas or low- or intermediate-grade ductal carcinoma in situ (<2 cm) received preoperative stereotactic radiosurgery and had a total of 186 mammograms available for review. At the second site, 180 mammograms from 25 patients with cT1-2 (<3 cm) unifocal invasive carcinomas treated with conventionally fractionated, preoperative APBI were reviewed. Findings were compared with those of 26 early stage breast cancers treated with conventional postoperative whole breast radiation therapy.
At a median follow-up of 61 months, 17 patients (55%) treated with single-dose APBI exhibited exuberant fat necrosis at the lumpectomy site. Fat necrosis was believed to be clinically palpable in 5 (16%) of these patients within the first 3 years of follow-up. Exuberant fat necrosis developed in 5 patients (20%) treated with fractionated APBI over a median 68-month follow-up period but only 2 of those patients (8%) who underwent conventional whole breast radiation therapy.
In situ tumor targeting in the preoperative setting allows relative sparing of normal tissue but results in a larger and more vigorous area of change on surveillance imaging, potentially reflecting the interaction of surgical resection with an irradiated tissue bed. High-dose stereotactic radiosurgery in particular increases the risk of developing a uniquely robust and well-demarcated pattern of fat necrosis on mammogram that may also present clinically. With many ongoing studies evaluating the preoperative treatment approach, defining the landscape of expected imaging sequelae will provide useful anticipatory guidance for clinicians and patients.
评估经立体定向放射外科或常规分割方案行术前加速部分乳房照射（APBI）的乳房 X 线摄影术后遗症。
这项多中心回顾性研究评估了两项前瞻性术前 APBI 临床试验中入组患者的监测性乳房 X 线照片。在一个部位，31 例 cT1N0 浸润性癌或低或中级别导管原位癌（<2cm）患者接受术前立体定向放射外科治疗，共可审查 186 张乳房 X 线片。在第二个部位，审查了 25 例接受常规分割、术前 APBI 治疗的 cT1-2（<3cm）单发浸润性癌患者的 180 张乳房 X 线片。结果与 26 例接受常规术后全乳放射治疗的早期乳腺癌患者的结果进行了比较。
在中位随访 61 个月时，17 例（55%）接受单次剂量 APBI 的患者在肿瘤切除术部位出现过度脂肪坏死。在随访的前 3 年内，认为 5 例（16%）患者的脂肪坏死具有临床可触及性。在中位随访 68 个月期间，5 例（20%）接受分割 APBI 的患者出现过度脂肪坏死，但仅 2 例（8%）接受常规全乳放射治疗的患者出现这种情况。
在术前环境中进行原位肿瘤靶向治疗可以相对保留正常组织，但在监测成像上会导致更大和更活跃的变化区域，这可能反映了手术切除与放射治疗组织床的相互作用。特别是高剂量立体定向放射外科会增加在乳房 X 线摄影上出现独特、强健且边界清晰的脂肪坏死模式的风险，这种情况也可能出现临床症状。随着许多正在进行的研究评估术前治疗方法，明确预期的影像学后遗症的特征将为临床医生和患者提供有用的前瞻性指导。
