Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, USA.
Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
Radiother Oncol. 2023 Jul;184:109668. doi: 10.1016/j.radonc.2023.109668. Epub 2023 Apr 6.
The role of post-mastectomy radiation therapy (PMRT) following primary systemic therapy (PST) in HER-2 positive breast cancer (Her2 + BC) remains poorly understood. The current study evaluates PMRT based on the pathological response to PST in Her2 + BC.
TRYPHAENA and NeoSphere are randomized phase II trials that investigated PST for Her2 + BC. Our study is a pooled analysis of both trials, including 312 node-positive patients treated with HER-2 targeted PST followed by mastectomy with or without PMRT. The primary endpoint is loco-regional recurrence-free survival (LRRFS).
Our analysis included 172 (55%) patients who achieved complete nodal pathological response (ypN0) and 140 (45%) patients who did not. Patients with ypN0 had a 5-year LRRFS of 97% in both, the PMRT and no PMRT, groups (p = 0.94). Patients with ypN + had 5-year LRRFS of 89% in the PMRT group and 82% in the no PMRT group (p = 0.17). Patients with ypN1 (n = 62) disease who received PMRT (n = 40) had a 5-year LRRFS of 85% as compared to 89% in those who did not (n = 22); (p = 0.60). A significant LRRFS difference was noted in patients with ypN2-3 (n = 78) disease who received PMRT (n = 53) compared to those who did not (n = 25) (5-year LRRFS 92% vs. 75%; p = 0.019). On multivariate analysis, clinical nodal disease at diagnosis and ypN0 were significantly associated with loco-regional recurrence (LRR).
Her2 + BC patients who achieve ypN0 after PST have excellent locoregional-control which supports de-escalation of PMRT. In contrast, patients with ypN2-3 disease derive significant benefit from PMRT. Clinical nodal stage at presentation and ypN0 status are significantly associated with LRR risk in Her2 + BC.
在人表皮生长因子受体 2 阳性乳腺癌（Her2+BC）中，接受初始系统治疗（PST）后行乳房切除术放疗（PMRT）的作用仍未被充分理解。本研究基于 PST 对病理反应评估 Her2+BC 中的 PMRT。
TRYPHAENA 和 NeoSphere 是两项针对 Her2+BC 的 PST 的随机 II 期试验。我们的研究是对这两项试验的汇总分析，共纳入 312 例接受抗 HER-2 靶向 PST 联合乳房切除术治疗且有或无 PMRT 的淋巴结阳性患者。主要终点是局部区域无复发生存（LRRFS）。
本分析纳入了 172 例（55%）完全淋巴结病理缓解（ypN0）患者和 140 例（45%）未缓解患者。ypN0 患者在 PMRT 和无 PMRT 两组的 5 年 LRRFS 分别为 97%（p=0.94）。ypN+患者在 PMRT 组的 5 年 LRRFS 为 89%，在无 PMRT 组为 82%（p=0.17）。ypN1（n=62）疾病患者接受 PMRT（n=40）的 5 年 LRRFS 为 85%，而未接受 PMRT（n=22）的为 89%（p=0.60）。ypN2-3（n=78）疾病患者接受 PMRT（n=53）的 5 年 LRRFS 显著高于未接受 PMRT（n=25）（92% vs. 75%；p=0.019）。多变量分析显示，诊断时临床淋巴结疾病和 ypN0 与局部区域复发（LRR）显著相关。
PST 后达到 ypN0 的 Her2+BC 患者局部区域控制效果极佳，支持 PMRT 降阶。相比之下，ypN2-3 疾病患者从 PMRT 中获益显著。在 Her2+BC 中，临床淋巴结分期和 ypN0 状态与 LRR 风险显著相关。
