INTRODUCTION An increasing number of breast cancer patients undergo breast-conserving surgery (BCS), but multiple ipsilateral breast cancer (MIBC) is still considered a relative contraindication for breast conservation. This study provides an update on trends in the surgical management for MIBC over a 10-year period. METHODS Nationwide data from the Netherlands Cancer Registration of all patients diagnosed with breast cancer between 2011 and 2021 were analysed. The primary outcomes of this study were the incidence of MIBC and the trend in breast surgery type among patients between 2011 and 2021. Secondary outcomes were the positive resection margin rates in patients treated with BCS, the proportion of patients requiring re-excision and overall survival. RESULTS In total, 114 433 patients (83%) with unifocal breast cancer and 23 932 patients (17%) with MIBC were identified. The incidence of MIBC was stable (17%) over the years. Overall BCS rates, both primary and after neoadjuvant chemotherapy, increased in MIBC from 29% in 2011 to 41% in 2021. Re-excision was performed in 1348 patients (n = 8455, 16%). The 5-year OS estimate for patients with MIBC treated with BCS was 93%. The pathological complete response (pCR) in MIBC patients treated with neoadjuvant chemotherapy followed by mastectomy was 23%. CONCLUSION The breast conservation rate in MIBC has increased over the last decade. In addition, 23% of MIBC patients treated with neoadjuvant chemotherapy followed by mastectomy achieved a pCR. This suggests increasing opportunities for even more BCS in MIBC.

中文翻译：

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增加多发性同侧乳腺癌保乳治疗的机会：荷兰全国性研究。


简介 越来越多的乳腺癌患者接受保乳手术（BCS），但多发性同侧乳腺癌（MIBC）仍然被认为是保乳的相对禁忌症。这项研究提供了 10 年来 MIBC 手术治疗趋势的最新情况。方法 对荷兰癌症登记中心 2011 年至 2021 年间所有诊断患有乳腺癌的患者的全国数据进行了分析。本研究的主要结果是2011年至2021年间患者中MIBC的发生率和乳腺手术类型的趋势。次要结果是接受BCS治疗的患者的阳性切除切缘率、需要再次切除的患者比例以及总生存期。结果 总共确定了 114 433 名单灶性乳腺癌患者 (83%) 和 23 932 名 MIBC 患者 (17%)。 MIBC 的发病率多年来保持稳定（17%）。 MIBC 的总体 BCS 率（包括初次化疗和新辅助化疗后）从 2011 年的 29% 增加到 2021 年的 41%。1348 名患者进行了再次切除（n = 8455，16%）。使用 BCS 治疗的 MIBC 患者的 5 年 OS 估计为 93%。接受新辅助化疗并随后进行乳房切除术的 MIBC 患者的病理完全缓解 (pCR) 为 23%。结论 MIBC 的乳房保留率在过去十年中有所增加。此外，接受新辅助化疗并随后进行乳房切除术的 MIBC 患者中有 23% 获得了 pCR。这表明 MIBC 中存在更多 BCS 的机会越来越多。