隐匿性乳腺癌临床病理特征及诊疗策略：附12例报告

Clinicopathologic characteristics, diagnosis and treatment strategies of occult breast cancer: a report of 12 cases

摘要:

背景与目的 隐匿性乳腺癌（OBC）是一种罕见的乳腺癌类型，其发病率低、难以找到乳腺原发病灶，使得临床医师对该病的定义和诊断模糊。同时，由于OBC的管理策略缺乏大样本的临床研究，因此OBC局部及全身治疗选择、预后信息对于临床医生来说颇具挑战。本研究通过对12例OBC的临床病理特征分析，总结诊疗流程，并结合国内外文献，对OBC诊疗策略进行讨论，以期给临床提供参考。方法 将2013年5月—2020年4月西安交通大学第一附属医院乳腺外科12例OBC患者纳入研究，对其临床病理特征、MRI表现、治疗方案、新辅助化疗疗效及预后进行了回顾性分析。结果 12例患者中位年龄53岁，组织学分型低分化腺癌、浸润性导管癌和单纯癌分别占66.7%、25.0%和8.3%，分子分型luminal B型、HER-2阳性型、三阴性型比例分别为41.7%、8.3%和50.0%，AJCC乳腺癌分期Ⅱ、Ⅲ和Ⅳ期分别占25.0%、58.3%和16.7%。9例（75.0%）MRI提示单侧腋窝淋巴结肿大，其中右侧3例，左侧6例。1例（8.3%）发现双侧腋窝淋巴结肿大。2例（16.7%）行MRI提示右侧腋窝淋巴结及右侧锁骨上淋巴结肿大。所有患者MRI均未发现乳腺部位可疑恶性病灶。10例非Ⅳ期的OBC患者中8例接受了乳腺癌改良根治术，2例仅接受腋窝淋巴结清扫术，2例初诊Ⅳ期的患者未接受手术。接受新辅助化疗共3例，达到病理学完全缓解（pCR）者2例。患者的中位随访时间为（43±14）个月。截至2022年7月，6例出现复发转移，其中3例因内脏转移死亡。结论 乳腺MRI检查在OBC的排除性诊断中有重要价值；OBC的治疗策略根据分子分型及淋巴结分期可选择新辅助治疗、乳腺癌改良根治术、腋窝淋巴结清扫术，术后酌情联合辅助放疗、化疗、内分泌治疗等。

Abstract:

Background and Aims Occult breast cancer (OBC) is a rare type of breast cancer with low incidence and difficulty in identifying the primary breast lesion, leading to a vague definition and diagnosis for healthcare professionals. Additionally, due to the lack of large-scale clinical studies on the management strategies for OBC, the local and systemic treatment options, as well as prognosis information, pose considerable challenges for clinicians. This study was performed to attempt to provide clinical references by analyzing the clinical and pathological characteristics of 12 cases of OBC, summarizing the diagnostic and therapeutic process, and discussing the diagnostic and treatment strategies for OBC based on domestic and international literature.Methods A retrospective analysis was conducted on 12 cases of OBC patients treated in the Department of Breast Surgery at the First Affiliated Hospital of Xi'an Jiaotong University from May 2013 to April 2020. The clinicopathologic characteristics, MRI findings, treatment strategies, efficacy of neoadjuvant chemotherapy, and prognosis of these patients were analyzed.Results Of the 12 patients, the median age was 53 years, histological subtypes consisted of poorly differentiated adenocarcinoma, infiltrating ductal carcinoma, and carcinoma simplex, accounting for 66.7%, 25.0%, and 8.3% respectively. The molecular subtypes were luminal B type, HER-2 positive type, and triple-negative type, with proportions of 41.7%, 8.3%, and 50.0% respectively. According to the AJCC staging, 25.0% were stage Ⅱ, 58.3% were stage Ⅲ, and 16.7% were stage Ⅳ. MRI findings indicated unilateral axillary lymph node enlargement in 9 cases (75.0%), with 3 cases on the right side and 6 cases on the left side. Bilateral axillary lymph node enlargement was found in 1 case (8.3%). MRI revealed axillary lymph node enlargement and supraclavicular lymph node enlargement on the right side in 2 cases (16.7%). No suspicious malignant lesions were detected in the breast region on MRI in any of the patients. Among the 10 patients with non-stage Ⅳ OBC, 8 underwent modified radical mastectomy, 2 underwent axillary lymph node dissection only, and 2 patients diagnosed with stage Ⅳ at initial presentation did not undergo surgery. Three patients received neoadjuvant chemotherapy, and two of them achieved pathological complete response (pCR). The median follow-up time was (43±14) months. As of July 2022, six patients experienced recurrence and metastasis, with three deaths attributed to visceral metastasis.Conclusion Breast MRI examination has important value in the exclusionary diagnosis of OBC. The treatment strategy for OBC can involve neoadjuvant therapy, modified radical mastectomy, axillary lymph node dissection based on molecular subtypes and lymph node staging. Postoperative adjuvant radiotherapy, chemotherapy, and endocrine therapy may be considered as adjunctive treatments.