对乳腺癌的新辅助全身治疗（NST）的响应可以个体化调整后续治疗。NST后进行成像引导的乳腺活检能够准确预测病理学完全缓解（pCR）。本临床试验的可行性阶段评估了在试验扩展之前省略乳腺手术后进行放疗对局部复发的影响。符合以下条件的乳腺癌病人可被纳入研究：病灶单中心、临床分期为cT1-2 N0-1 M0的三阴性乳腺癌（TNBC）或表皮生长因子受体2阳性乳腺癌（HER2+BC），在NST后成像研究中，残余病灶直径小于2cm。如果成像引导的抽吸活检（VACB）未发现残余腺体内或腺体外浸润病变，则可省略乳腺手术并进行放疗。可行性阶段的主要终点是6个月内同侧乳腺肿瘤复发情况。如果在可行性阶段出现任何复发，试验将停止。从2017年3月至2018年10月，共纳入13名病人。平均年龄60.8岁（范围51至75岁），大部分为白人（69.2%）和非拉丁裔（84.6%）。所有病人均为浸润性导管癌（6例TNBC，7例HER2+BC）。NST前平均病灶大小为2.4cm（范围0.9至5.0cm），NST后为0.7cm（范围0至1.8cm）。7例病人（53.8%）在VACB中发现残余病灶，剩下的6例（46.2%）构成了可行性队列。在中位随访时间为44.3个月（范围41.3至51.3个月）内，这个队列中没有同侧乳腺肿瘤复发。这些早期数据表明，在经过NST后，对于没有残余病灶的TNBC和HER2+BC患者，省略乳腺手术是可行的。该临床试验扩展阶段的结果将按照预先规定的分析方案进行报告。版权所有©2023年美国外科医师学会。由Wolters Kluwer Health，Inc出版。保留所有权利。

Response to neoadjuvant systemic therapy (NST) for breast cancer enables tailoring of subsequent therapy. Image-guided breast biopsy after NST can accurately predict a pathologic complete response (pCR). The feasibility phase of the clinical trial reported here assesses omission of breast surgery followed by radiotherapy in terms of local recurrence before trial expansion.Women with unicentric, cT1-2 N0-1 M0 triple-negative (TNBC) or human epidermal growth factor receptor 2-positive breast cancer (HER2+BC) cancer with <2 cm residual disease on post-NST imaging were eligible to enroll. If no residual invasive or in situ disease was identified by image-guided, vacuum-assisted core biopsy (VACB), breast surgery was omitted, and radiotherapy delivered. The primary endpoint for the feasibility phase was ipsilateral breast tumor recurrence at 6 months. If any recurrence occurred during the feasibility phase the trial would halt.Thirteen patients were enrolled from March 2017 to October 2018. The mean age was 60.8 years (range 51 to 75) and most patients were White (69.2%) and non-Hispanic/Latino (84.6%). All patients had invasive ductal carcinoma (6 TNBC, 7 HER2+BC). Mean tumor size was 2.4 cm (range 0.9 to 5.0) before NST and 0.7 cm (range 0 to 1.8) after NST. Seven patients (53.8%) had residual disease identified on VACB; the remaining 6 (46.2%) comprised the feasibility cohort. At a median follow-up of 44.3 months (range 41.3 to 51.3) there was no ipsilateral breast tumor recurrence in this cohort.These early data suggest that omission of breast surgery in patients with invasive TNBC and HER2+BC with no evidence of residual disease on standardized VACB after NST is potentially feasible. Results from the expansion phase of this clinical trial will be reported per protocol prespecified analyses.Copyright © 2023 by the American College of Surgeons. Published by Wolters Kluwer Health, Inc. All rights reserved.