Value of the US BI-RADS final assessment following mastectomy: BI-RADS 4 and 5 lesions

Abstract

Clinical examination is not entirely sufficient for evaluation of the postoperative site for follow-up of patients with mastectomy. A few studies have reported that postoperative follow-up US evaluation allows early detection and proper management of local tumor recurrence. To evaluate the diagnostic performance of the American College of Radiology (ACR) ultrasonographic (US) Breast Imaging Reporting and Data System (BI-RADS) categories 4 and 5 breast lesions at the mastectomy site. Our institutional review board approved this study and waived the need for informed consent. We retrospectively reviewed the consecutive post-mastectomy US exams for palpable and non-palpable lesions in the post-mastectomy chest wall that were categorized as BI-RADS 4 (subcategorized 4a, 4b, and 4c) or 5 between January 2007 and April 2010. The positive predictive value (PPV) for final assessment was evaluated. From 2681 post-mastectomy US examinations, we obtained a study population of 50 patients with 50 lesions (20 palpable, 30 non-palpable). There were nine (45%) malignancies among the palpable lesions and six (20%) malignancies among the non-palpable lesions. The palpability showed no significant correlation with malignancy in overall subcategorization (P >0.05). The PPVs of categories 4 and 5 were 14.3% for category 4a, 62.5% for category 4b, 100% for category 4c, and 100% for category 5. The ACR US BI-RADS categorization of 4a, 4b, 4c, and 5 for breast lesions at the mastectomy site is a feasible method for predicting local recurrence. All lesions should be managed according to US characteristics during evaluation of local recurrence at the mastectomy site, regardless of palpability.