Outcomes of Return to Routine Screening for BI-RADS 3 Lesions Detected at Supplemental Automated Whole-Breast Ultrasound in Women With Dense Breasts: A Prospective Study.

Abstract

<b>BACKGROUND.</b> Supplemental screening breast ultrasound (US) detects additional cancers in women with dense breasts but identifies many BI-RADS 3 lesions that result in short-term follow-up and biopsies. <b>OBJECTIVE.</b> The purpose of this study was to evaluate outcomes in patients recommended for return to routine screening for lesions assessed as BI-RADS 3 on supplemental automated whole-breast US. <b>METHODS.</b> This prospective study invited patients with BI-RADS 1 or 2 on screening mammography and breast density C or D to undergo supplemental automated breast US (ABUS). ABUS was interpreted as BI-RADS 1, 2, 3, or 0. Return to routine screening was recommended for ABUS BI-RADS 1, 2, or 3. ABUS BI-RADS 0 lesions underwent targeted handheld US. Remaining patients were followed for 2 years. Malignancy rates were compared using Fisher exact tests. <b>RESULTS.</b> A total of 2257 women (mean age, 58.0 ± 11.2 [SD] years) were included. Supplemental ABUS was scored as BI-RADS 1 in 1186 (52.5%) women, BI-RADS 2 in 591 (26.2%), BI-RADS 3 in 395 (17.5%), and BI-RADS 0 in 85 (3.8%). A total of 394 patients with ABUS BI-RADS 3 had 2-year follow-up, during which no cancer (0%; 95% CI, 0.0-0.9%) was diagnosed in the quadrant of the lesion. Among patients with 2-year follow-up, breast cancer was diagnosed in 4/1117 (0.4%) with ABUS BI-RADS 1, 2/556 (0.4%) with ABUS BI-RADS 2, and 2/394 (0.5%) with ABUS BI-RADS 3 (cancer in other quadrant than the lesion). Malignancy rates were not different between ABUS BI-RADS 1, 2, and 3 (<i>p</i> = .28). The ABUS recall rate was 3.8% (85/2257; 95% CI, 3.6-4.0%). If short-term follow-up had been recommended for ABUS BI-RADS 3, the ABUS recall rate would have been 21.3% (480/2257, 95% CI 19.6-23.0%). The biopsy rate was 0.5% (12/2257; 95% CI, 0.3-0.9%); the positive biopsy rate was 58.3% (7/12). One of seven cancers diagnosed by initial supplemental ABUS and none of eight cancers diagnosed during subsequent follow-up were node-positive cancer. <b>CONCLUSION.</b> Return to routine screening for ABUS BI-RADS 3 lesions results in a substantial decrease in recall rate and is unlikely to result in an adverse outcome. <b>CLINICAL IMPACT.</b> This prospective study supports a recommendation for routine annual follow-up for BI-RADS 3 lesions at supplemental ABUS. <b>TRIAL REGISTRATION.</b> ClinicalTrials.gov NCT02650778.