Vertido Anna, McKenzie Tesia, Othieno Alisha, Quirarte Astrid, Kaur Mandeep, Abel Mary Kathryn, Chung Maggie, Lee Amie Y, Mukhtar Rita A
Division of Surgical Oncology, Department of Surgery, University of California San Francisco, San Francisco, CA, USA.
Division of Breast Surgery, Riverview Medical Center, Hackensack Meridian Health, Shrewsbury, NJ, USA.
Ann Surg Oncol. 2025 Jun 27. doi: 10.1245/s10434-025-17735-6.
Invasive lobular carcinoma (ILC) is the second most common subtype of breast cancer, comprising 10-15% of cases. Due to its diffuse growth pattern, conventional imaging techniques have decreased sensitivity for ILC. While breast magnetic resonance imaging (MRI) is often recommended for ILC, its accuracy following neoadjuvant therapy is unknown. We evaluated the accuracy of post-treatment MRI and examined the impact on surgical outcomes.
We retrospectively analyzed 129 patients with ILC who underwent neoadjuvant chemotherapy (NAC) or endocrine therapy (NET) and had post-treatment MRI. We considered a 0.5 cm difference between longest tumor diameter on MRI and pathologic tumor size to be discrepant. Tumor imaging phenotype was categorized as mass, non-mass enhancement (NME), or mass + NME. We evaluated concordance between imaging and pathology by tumor phenotype and associations with positive margin rates using Stata 18.0.
Post-treatment MRI underestimated tumor size in 52.5% of cases, was concordant in 25.3%, and overestimated in 22.2%. The presence of NME was associated with a higher rate of tumor size underestimation (62.5% versus 39.5% for mass only, p = 0.023); mean underestimation was 3.4 cm in those with NME. Underestimation was associated with higher positive margin rates following breast-conserving surgery (p = 0.018). Finally, among patients with complete imaging response on MRI, 93.3% had residual invasive disease on pathology.
Following neoadjuvant therapy, post-treatment MRI frequently underestimates tumor size in ILC, particularly in tumors with NME. Surgeons should consider these imaging limitations when planning resection, which could improve surgical outcomes.
浸润性小叶癌（ILC）是乳腺癌的第二大常见亚型，占病例的10 - 15%。由于其弥漫性生长模式，传统成像技术对ILC的敏感性降低。虽然通常推荐对ILC进行乳腺磁共振成像（MRI）检查，但其在新辅助治疗后的准确性尚不清楚。我们评估了治疗后MRI的准确性，并研究了其对手术结果的影响。
我们回顾性分析了129例接受新辅助化疗（NAC）或内分泌治疗（NET）并进行了治疗后MRI检查的ILC患者。我们将MRI上最长肿瘤直径与病理肿瘤大小相差0.5 cm视为不一致。肿瘤成像表型分为肿块型、非肿块强化（NME）型或肿块 + NME型。我们使用Stata 18.0评估成像与病理之间按肿瘤表型的一致性以及与切缘阳性率的相关性。
治疗后MRI在52.5%的病例中低估了肿瘤大小，25.3%的病例中两者一致，22.2%的病例中高估了肿瘤大小。NME的存在与更高的肿瘤大小低估率相关（仅肿块型为39.5%，NME型为62.5%，p = 0.023）；NME型患者的平均低估为3.4 cm。低估与保乳手术后更高的切缘阳性率相关（p = 0.018）。最后，在MRI上显示完全影像学缓解的患者中，93.3%的患者病理上有残留浸润性疾病。
新辅助治疗后，治疗后MRI经常低估ILC的肿瘤大小尤其是有NME的肿瘤。外科医生在计划切除时应考虑这些成像局限性，这可能改善手术结果。
