Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Johns Hopkins School of Medicine, Baltimore, MD, USA.
Br J Radiol. 2021 Mar 1;94(1119):20201202. doi: 10.1259/bjr.20201202. Epub 2021 Jan 5.
Defining the posterior extent of breast cancer prior to surgery has clinical implications. However, there are limited data available to guide the interpretation of breast cancers seen on MRI that abut the pectoralis muscle but lack associated muscle enhancement.
In this retrospective study of breast MRIs performed between May 2008 and July 2019, 43 female patients demonstrated breast cancers abutting the pectoralis muscle without enhancement of the muscle itself. Imaging features of the cancers as well as pathologic and clinical outcomes were recorded. Statistical analyses of associations between imaging findings and clinical outcomes were performed using Fisher's exact test, logistic regression, a Mann-Whitney test and/or Student's -test.
The pectoralis major muscle was pathologically invaded by carcinoma in 4/43 (9.3%). There was no significant association between pectoralis muscle invasion and any MR imaging feature of the breast cancer. Tumors causing deformation of the muscle contour by MRI, tumors larger in size, tumors with a larger extent abutting the muscle and tumors in which the imaging feature abutting the muscle was a mass or non-mass enhancement (rather than a spicule) were more commonly seen in patients with muscle invasion, although these did not reach statistical significance ( > 0.05).
In this study, a lack of pectoralis muscle enhancement by MRI did not exclude pathologic muscle invasion by breast cancers abutting the muscle.
Knowledge of the likelihood of pectoralis muscle involvement for breast cancers abutting the pectoralis muscle on MRI may guide accurate interpretation and definition of the posterior extent of disease.
在术前确定乳腺癌的后向范围具有临床意义。然而，目前可用的数据有限，无法指导解释在 MRI 上看到的紧贴胸肌但缺乏相关肌肉增强的乳腺癌。
在这项回顾性研究中，纳入了 2008 年 5 月至 2019 年 7 月间进行的 43 例女性乳腺 MRI 检查，这些患者的乳腺癌紧贴胸肌，但胸肌本身没有增强。记录了癌症的影像学特征以及病理和临床结果。使用 Fisher 精确检验、逻辑回归、Mann-Whitney 检验和/或 Student's t 检验对影像学发现与临床结果之间的关联进行统计学分析。
43 例患者中有 4 例（9.3%）胸大肌被癌侵犯。乳腺癌的胸肌侵犯与任何 MRI 影像学特征均无显著相关性。通过 MRI 引起肌肉轮廓变形的肿瘤、较大的肿瘤、与肌肉更广泛接触的肿瘤以及影像学特征紧贴肌肉的肿瘤为肿块或非肿块样强化（而非刺状）的肿瘤，更常见于有肌肉侵犯的患者，尽管这些差异无统计学意义（>0.05）。
在这项研究中，MRI 上缺乏胸肌增强并不能排除紧贴胸肌的乳腺癌对胸肌的病理侵犯。
了解 MRI 上紧贴胸肌的乳腺癌发生胸肌侵犯的可能性，可能有助于准确解释和确定疾病的后向范围。
