Keywords:
Breast, Ultrasound
Authors:
S. H. Park1, E.-K. Kim2, M. J. Kim2, J. Y. Kwak2, S. J. Kim2; 1Incheon/KR, 2Seoul/KR
DOI:
10.1594/ecr2010/C-0442
Methods and Materials
I. CASE SELECTION
Between July 2005 and July 2007, 3124 ultrasound guided-14 gauge core needle biopsies (US-14G-CNBs) of breast masses were performed at the breast imaging center at our institution. Among the lesions, 78 lesions were pathologically-determined to be DCIS.
Inclusion criteria was a histopathologically-proven pure DCIS without signs of micro-invasion or invasive cancer, as determined by the use of light microscopy.
- DCIS with micro-invasion was defined as tumor cells, singly or in clusters, that infiltrated the periductal stroma or were seen as a projection of neoplastic cells through a disrupted basement membrane in continuity with the DCIS, measuring < 1 mm in the greatest dimension.
Exclusion criteria: Excluding lesions with microinvasion (n = 9), 69 pure DCIS lesions in 60 patients that manifested as identifiable masses with or without calcifications as depicted on ultrasound (US) were included in the study population. Six patients had two separate lesions and one patient had four separate lesions.
II.IMAGE AND CLINICAL ANALYSIS
IMAGE ANALYSIS
- Two radiologists retrospectively reviewed the mammographic and sonographic findings of the DCIS lesions in consensus.
1. Mammography
- The mammographic characteristics of the lesions were classified as negative, calcifications only, a mass, a mass with calcifications, asymmetry, and asymmetry with calcifications.
2. US
- Sonographic characteristics of size, shape, orientation, margin, lesion boundary, and echogenicity of the nodules according to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS®) lexicon were reviewed retrospectively.
- Lesion size : the maximum lesion diameter as measured on US.
- An abnormal lymph node was defined as a thickened or eccentrically bulging cortex with a diminished or absent hilum as depicted on US in accordance with previous reports.
3. Clinical review
- Clinical records for 60 patients were reviewed to determine age and symptoms at the time of presentation.
BIOPSY PROCEDURE
- A US-14G-CNB was performed using a free hand technique and a high-resolution sonography unit with a 7.5- or 12-MHz linear array transducer. All procedures were performed using an automated gun and 14-gauge Tru-Cut needles with a 22 mm throw.
- One of five radiologists specializing in breast imaging performed all of the biopsies. Prior to a biopsy, a breast US (including the bilateral axillae) was meticulously performed. A minimum of five biopsy samples were obtained with additional samples at the discretion of the radiologist.
- The pathologic results of the US-14G-CNBs for each case were retrospectively reviewed with the final pathology findings as determined after breast surgery.
DATA ANALYSIS
- The results of the US-14G-CNBs were correlated with the subsequent surgical (lumpectomy or mastectomy) histologic findings.
- Axillary lymph node status was determined after a sentinel lymph node biopsy or axillary lymph node dissection.
- The rate of underestimation was defined as a diagnosis of DCIS after a US-14G-CNB with a pathologic diagnosis of invasive carcinoma following surgery.
- The underestimated group was defined as DCIS after a US-14G-CNB in which the cases were subsequently determined to be invasive ductal carcinoma (IDC) following surgical excision.
- The non-underestimated group consisted of accurately diagnosed cases of DCIS after a US-14G-CNB in which the cases were not invasive following surgical excision.
- The underestimated and non-underestimated groups were compared in terms of clinical symptoms, mammographic findings and sonographic characteristics, including axillary findings.
STATISTICAL ANALYSIS
- Tests for statistical significance were performed with statistical software. A p < 0.05 was considered significant.
- Statistical comparisons were performed using the chi-squared test (Fisher’s exact test) for categorical variables and the independent t-test for continuous variables.
- Confidence intervals were calculated according to the formula by developed by Berry.