To examine the clinicopathological characteristics and the influencing factors of the residual tumor of patients with Breast Image Report and Data System (BI-RADS) grade 3 lesions diagnosed with malignancy after minimally invasive excision.

In this retrospective case-control study, clinicopathological data of 69 cases, which had been evaluated as BI-RADS 3 lesions by ultrasound (4 151 cases) diagnosed with breast cancer by minimally invasive excision pathology, were analyzed between May 2012 and June 2016 at the Department of Breast Surgery of the Second Hospital of Shandong University and Linyi People′s Hospital. All patients were female, aged (43.4±8.2) years (range: 22 to 70 years). Based on residual tumor after minimally invasive excision, patients were classified into two subgroups: tumor residual group (n=39) and non-tumor residual group (n=30). The clinicopathological features between the two groups were compared. The differences in clinicopathological characteristics were compared in different groups using the χ² test and the t test. Potential variables identified in the univariate analysis and other relevant variables will be analyzed multivarially using Logistic regression models. The Kaplan-Meier method was applied for survival analysis and survival curves.

The breast cancer detection rate of ultrasound BI-RADS 3 lesions was 1.66% (69/4 151), and their maximum diameter of the masses was (1.27±0.45) cm (range: 0.5 to 2.3 cm). Among them, the maximum diameter were ≤1 cm in 28 cases and >1 cm in 41 cases. Histopathological results showed carcinoma in situ in 24 cases and invasive carcinoma in 41 cases, positive expression of the estrogen receptor in 47 cases, positive expression of the progesterone receptor in 43 cases, Ki-67 proliferation index elevated in 26 cases. Axillary metastasis positive rate was 10.1% (7/69). Residual tumor after minimally invasive surgery was found in 39 cases (56.5%). Univariate analysis showed that the tumour residual group showed a significantly increased rate of positive expression of the estrogen receptor (91.9%(34/37) vs. 61.9%(13/21), χ²=7.838, P=0.012). In multivariate analysis, the only variable found to significantly affect the residual tumor was the positive expression of the estrogen receptor (OR=16.852, 95%CI: 1.819 to 156.130, P=0.013). The 5-year disease-free survival rate of breast cancer patients with breast ultrasound BI-RADS 3 lesions was 97.1% and the overall survival rate was 98.6%.

BI-RADS 3 lesions diagnosed by ultrasound undergoing ultrasound-guided minimally invasive excision have a certain risk of detected malignancy, approximately 1.66%. Patients with positive expression of the estrogen receptor are more likely to develop residual tumor. A secondary operation should be considered to ensure that no tumor residues remain in the cavity.

Breast neoplasms; Biopsy; Minimally invasive excision; Residual tumor; Prognosis