Follow-up Recommendations for Young, Average Risk Women With BI-RADS 3 Masses

To determine the outcome and malignancy rate of BI-RADS 3 masses during follow-up at 6, 12, and 24 months.

This retrospective cohort study identified female patients <35 years of age with an oval, parallel, circumscribed mass assigned a BI-RADS 3 assessment on US from January 2014 to December 2021. Inclusion criteria were average risk women with a 6-month follow-up US and either (1) ≥18 months of follow-up imaging or (2) surgical excision/biopsy. Initial US lesion characteristics; follow-up BI-RADS assessments at 6, 12, 18, and 24 months; and pathology results were recorded.

There were 662 patients with a BI-RADS 3 mass on US, of whom 191 were patients (mean age 26.4 ± 6.0 years) with 228 lesions (mean size 1.6 ± 0.7 cm) who met inclusion criteria. Most lesions exhibited either 2-year stability (56%, 128/228) or decreased in size/resolved (8%, 18/228). In all, 31% (71/228) of lesions were biopsied, most commonly because of increasing size (93%, 66/71). Most enlarging lesions underwent biopsy at the 6-month follow-up (68%, 45/66). All 71 lesions recommended for biopsy were fibroadenomas with a positive predictive value and malignancy rate of 0%. No phyllodes tumors were detected.

There were no cancers among young female patients with probably benign (BI-RADS 3) masses on US. A single 6-month imaging follow-up and then ongoing clinical surveillance may be sufficient in assessing probably benign masses in young women aged <35 years.