Background/Objectives: HER2-positive breast cancer (HER2+BC) is an aggressive subtype, with neoadjuvant treatment (NAT) aiming to achieve a pathological complete response (pCR) to improve long-term outcomes. Trastuzumab emtansine (T-DM1) has been established as the standard of care in the adjuvant setting for HER2+BC patients who do not obtain pCR. The ATD study aimed to evaluate the real-world tolerability of T-DM1 in this setting. The secondary objective was to assess the effectiveness. Methods: This was a multicenter, retrospective study across 24 Italian oncology centers, including 410 patients with HER2+BC treated with adjuvant T-DM1 following a lack of pCR after NAT. Patient characteristics, NAT regimens, and surgical outcomes were recorded. Tolerability was assessed by documenting adverse events (AEs) according to the CTCAE (v5.0). Preliminary effectiveness was evaluated in terms of relapse-free survival (RFS) and overall survival (OS). Results: Overall, 228 patients (55.6%) experienced at least one AE related to T-DM1, with 4.9% experiencing grade 3 or higher AEs. The most common AEs were hepatotoxicity (18.5%) and thrombocytopenia (17.6%). T-DM1 was discontinued in 10.0% of patients due to toxicity. After a median follow-up of 25 months, 31 relapse events (7.6%) and 22 deaths (5.4%) were reported. The preliminary incidence of RFS and OS events was similar between patients who completed the T-DM1 course and those who discontinued it early. Conclusions: T-DM1 demonstrated a manageable safety profile, and the adverse events were consistent with those reported in randomized trials. The data are not yet sufficient to allow for a formal analysis of RFS and OS, and long-term follow-up is required.
背景/目的：HER2阳性乳腺癌（HER2+BC）是一种侵袭性亚型，新辅助治疗（NAT）旨在实现病理学完全缓解（pCR）以改善长期预后。对于未达到pCR的HER2+BC患者，恩美曲妥珠单抗（T-DM1）已被确立为辅助治疗的标准方案。ATD研究旨在评估T-DM1在此背景下的真实世界耐受性，次要目标是评估其有效性。方法：这是一项在意大利24个肿瘤中心开展的多中心回顾性研究，共纳入410例在NAT后未达到pCR并接受辅助T-DM1治疗的HER2+BC患者。研究记录了患者特征、NAT方案和手术结果。根据CTCAE（v5.0）标准记录不良事件（AEs）以评估耐受性。通过无复发生存期（RFS）和总生存期（OS）评估初步有效性。结果：总体而言，228例患者（55.6%）经历了至少一次与T-DM1相关的AE，其中4.9%的患者出现3级或以上AE。最常见的AE是肝毒性（18.5%）和血小板减少症（17.6%）。10.0%的患者因毒性反应停用T-DM1。中位随访25个月后，报告了31例复发事件（7.6%）和22例死亡（5.4%）。完成T-DM1疗程的患者与早期停药患者的RFS和OS事件初步发生率相似。结论：T-DM1显示出可控的安全性特征，其不良事件与随机试验报告一致。现有数据尚不足以对RFS和OS进行正式分析，需要长期随访。
肿瘤(癌症)患者之家