Yale University School of Medicine, Department of Pathology, New Haven, CT, USA.
Montefiore Medical Center, Department of Pathology, New York, NY, USA.
Hum Pathol. 2023 Dec;142:15-19. doi: 10.1016/j.humpath.2023.10.002. Epub 2023 Nov 14.
Although mucinous carcinoma (MC) is considered a favorable histologic subtype of invasive breast cancer (BC), a subset of MC is managed with neoadjuvant therapy (NAT). The clinical and pathologic features of MC following NAT are not well characterized. The aim of this study is to characterize pathologic response in patients with MC treated with NAT, including neoadjuvant endocrine therapy (NET), neoadjuvant chemotherapy (NCT), and Herceptin-targeted NCT (H-NCT). We conducted a retrospective cohort study of 28 patients with MC who received preoperative adjuvant therapy followed by resection from three institutions between 2010 and 2020. Demographic and clinical information were retrieved from the medical records. Pathologic review of the post NAT resection specimens was performed including tumor grading, tumor size, staging, residual tumor cellularity, estrogen receptor (ER) and HER2 status. Nine (32 %) patients with ER+/HER2- MC received NET, 8 (29 %) ER+/HER2- MC were treated with NCT only and 11 (39 %) HER2+ MC received HER2-targeted NCT (H-NCT). The HER2+ MC patients were younger (45 vs. 64 years; p = 0.006). The HER2+ MC were of higher grade (p = 0.03) and more likely to be multifocal (p = 0.008). Only 2 of 28 (7 %) MC (both HER2+) showed complete pathologic response with residual acellular mucin pools. Persistent mass-forming mucin pools were present in 26 (93 %) cases. The residual tumor cellularity was markedly reduced (≤5 %) in H-NCT treated MC (11/11, 100 %), followed by NET group (6/9, 67 %) and NCT only group (4/8, 50 %) (p = 0.011). Similarly, a higher rate of pathologic response (pCR/RCB-I) was observed in H-NCT (7/11, 64 %), followed by NET group (5/9, 56 %), and NCT only group (1/7, 13 %) (p = 0.053). Post-therapy, all HER2+ MC were smaller than 2 cm and ypT size was significantly smaller in H-NCT group (11/11, 100 %) versus combined NET (5/9, 55 %) and NCT only groups (4/8, 50 %) (p = 0.029). We conclude that ER-/HER2+ and ER+/HER2-mucinous carcinomas of the breast show robust pathological response to neoadjuvant HER2 targeted and endocrine therapy, respectively. Our findings suggest that MC may show good response to endocrine therapy.
虽然黏液癌（MC）被认为是浸润性乳腺癌（BC）的一种有利组织学亚型，但 MC 的一部分需要接受新辅助治疗（NAT）。接受 NAT 后的 MC 的临床和病理特征尚未得到很好的描述。本研究的目的是描述接受 NAT 治疗的 MC 患者的病理反应，包括新辅助内分泌治疗（NET）、新辅助化疗（NCT）和曲妥珠单抗靶向 NCT（H-NCT）。我们对 2010 年至 2020 年间在三家机构接受术前辅助治疗后行切除术的 28 例 MC 患者进行了回顾性队列研究。从病历中检索人口统计学和临床信息。对 NAT 切除标本进行病理复查，包括肿瘤分级、肿瘤大小、分期、残留肿瘤细胞密度、雌激素受体（ER）和 HER2 状态。9 例（32%）ER+/HER2-MC 患者接受 NET 治疗，8 例（29%）ER+/HER2-MC 患者仅接受 NCT 治疗，11 例（39%）HER2+MC 患者接受曲妥珠单抗靶向 NCT（H-NCT）治疗。HER2+MC 患者更年轻（45 岁 vs. 64 岁；p=0.006）。HER2+MC 分级更高（p=0.03）且更有可能呈多灶性（p=0.008）。仅 28 例 MC 中有 2 例（均为 HER2+）表现为残留无细胞黏液池的完全病理缓解。26 例（93%）中仍存在实性黏液肿块。H-NCT 治疗的 MC 中残留肿瘤细胞密度明显降低（≤5%）（11/11，100%），其次是 NET 组（6/9，67%）和仅 NCT 组（4/8，50%）（p=0.011）。同样，H-NCT 组的病理缓解率（pCR/RCB-I）更高（7/11，64%），其次是 NET 组（5/9，56%）和仅 NCT 组（1/7，13%）（p=0.053）。治疗后，所有 HER2+MC 的大小均小于 2cm，且 H-NCT 组的 ypT 大小明显小于 NET 组（5/9，55%）和仅 NCT 组（4/8，50%）（p=0.029）。我们得出结论，ER-/HER2+和 ER+/HER2-的乳腺黏液癌分别对新辅助 HER2 靶向和内分泌治疗有明显的病理反应。我们的研究结果表明，MC 可能对内分泌治疗有良好的反应。
