ABUS for Early-stage Breast Cancer
ABUS for Early-stage Breast Cancer
While the role of automated breast ultrasound (ABUS) as an alternative to hand-held
 ultrasound (HHUS) in breast cancer screening has been established, the use of ABUS in
 preoperative evaluation of newly diagnosed breast cancer patients is still limited. This may
 be because axillary areas are not included in the scanning area of ABUS. Newly diagnosed
 breast cancer patients have undergone axillary US to predict axillary lymph node metastasis
 before surgery, in combination with preoperative breast US, in many institutions. However,
 recent studies have reported that sentinel lymph node biopsy alone is sufficient for
 diagnosis and treatment of axillae of patients with early-stage breast cancer, because the
 incidence of axillary lymph node metastasis is very low. Therefore, the clinical significance
 of preoperative axillary US is being lowered in patients with early-stage breast cancers.
 Thus, considering that coronal images provided by ABUS may be more advantageous for detection
 of multifocal or multicentric cancer, we hypothesized that ABUS could replace HHUS in
 preoperative staging of patients with early-stage breast cancers (clinical Tis, T1-2/N0
 cancers) for whom preoperative axillary US is not necessary. The purpose of this study was to
 prospectively compare the diagnostic performances of ABUS and HHUS in preoperative evaluation
 of patients with early-stage breast cancers. This study will be conducted with institutional
 review board approval, and written informed consent will be obtained. From the Jan 2019 to
 Dec 2021, 675 patients diagnosed with early-stage breast cancer will be enrolled from the
 three institutions. Both ABUS and HHUS will be performed on each patient before surgery.
 Breast radiologists independently review ABUS and HHUS images. They detect all visible
 lesions and record the location and size of them. They characterize all detected lesions by
 using BI-RADS category. The primary object is to compare the diagnostic performance of ABUS
 and HHUS as preoperative staging tool in women with known breast cancers. The sensitivities
 and specificity of each US mode for the detection of breast cancers are calculated on a
 per-lesion basis. McNemar's test and Fisher's exact test are used to compare the
 sensitivities and PPVs for ABUS and HHUS. Significance testing on the lesion level and
 patient level is conducted using generalized estimating equations (GEEs) with a logit link
 and an independent working correlation structure to adjust the effect of clustering on
 radiologists and patients. GEEs are utilized to compare the sensitivities and PPVs for ABUS
 and HHUS. Diagnostic performance are assessed with receiver operating characteristics curve
 analysis. Area under the curves are calculated from both parametric and trapezoidal curve
 fitting. Agreements between tumor size measured by each US mode and pathologic the tumor size
 are analyzed with the intraclass correlation coefficient (ICC) and 95% Bland-Altman limits of
 agreement.
Inclusion Criteria:

 -  Patients with early-stage breast cancer (clinical Tis, T1- T2 cancers are suspected on
 mammography at the time of diagnosis), without palpable nodes at physical examination
 (N0)

 -  Patients who schedule to undergo surgery and sentinel lymph node biopsy

 -  Patient's age between 25-69 years

 -  Patients who voluntarily agree to participate in this study

 Exclusion Criteria:

 -  A history of previously treated breast cancers

 -  Patients who undergo excision biopsy for diagnosed breast cancer

 -  Pregnant or lactating women

 -  Patients who have breast implants