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

Background: 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-ups and biopsies. Objective: To evaluate outcomes in patients recommended for return to routine screening for lesions assessed as BI-RADS 3 on supplemental automated whole-breast US (ABUS). Methods: This prospective study invited patients with BI-RADS 1 or 2 on screening mammography and breast density C or D to undergo supplemental 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 hand-held US. Remaining patients were followed for 2 years. Malignancy rates were compared using Fisher s exact tests. Results: A total of 2257 women (mean age, 58.0±11.2 years) were included. Supplemental ABUS was scored as BI-RADS 1 in 1186 (52.5%), 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 (p=.28). 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, ABUS recall rate would have been 21.3% (480/2257, 95% CI 19.6%-23.0%). Biopsy rate was 0.4% (12/2257; 95% CI 0.3%-0.9%); positive biopsy rate was 58.3% (7/12). One of 7 patients diagnosed with cancer by initial supplemental ABUS, and none of 8 patients diagnosed with cancer during subsequent follow-up, had node-positive cancer. Conclusions: Return to routine screening for ABUS BI-RADS 3 lesions results in a substantial decrease in recall rate, while being unlikely to result in adverse outcome. Clinical Impact: This prospective study supports a recommendation for routine annual follow-up for BI-RADS 3 lesions at supplemental ABUS.