E2598. Risk of Malignancy Following a Probably Benign (BI-RADS 3) Masses on Ultrasound in Young Women
  1. Katie Shpanskaya; Duke University Health System
  2. Lars Grimm; Duke University Health System
  3. Sujata Ghate; Duke University Health System
To determine risk of malignancy of probably benign (BI-RADS 3) masses in young, average-risk female patients with short-term (6-month) follow-up.

Materials and Methods:
We conducted an IRB-approved, retrospective review of all female patients less than 35 years of age with a solid mass assigned BI-RADS 3 assessment on ultrasound from January 2015 to March 2020. Inclusion criteria were 6-month follow up ultrasound and either (a) 18 months or more of follow up imaging or (b) surgical excision/biopsy. Patients were excluded due to a lack of 6-month follow-up ultrasound (n = 145), insufficient follow-up or biopsy (n = 203), a high-lifetime breast cancer risk (n = 17) and a personal history of malignancy (n = 4). Initial ultrasound lesion characteristics, follow-up BI-RADS assessments at 6-, 12-, 18- and 24-months, and pathology results were recorded. Biopsy recommendation rate (BRR), positive predictive value (PPV) and malignancy rate were analyzed. Note was made of any phyllodes tumors as these benign lesions warrant surgical excision.

A total of 543 patients had a BI-RADS 3 mass on ultrasound, of which 174 patients with 211 lesions met inclusion criteria. Among those, 34 patients with 41 lesions underwent immediate biopsy or surgical excision predominantly due to patient request (30/34 patients; 88%). 140 patients (mean age 26.5 ± 5.8 years) with 170 lesions (mean size 1.6 ± 0.7 cm) underwent short-term (6-month) follow-up. Patients demonstrated either long-term stability (n = 78 patients, 94 lesions), biopsy (n = 55 patients, 61 lesions), or decrease/resolution (n = 13 patients, 15 lesions). The biopsy recommendation rate was 30%, most commonly due to increasing lesion size (n= 48; 79%). Most lesions underwent biopsy at the 6-month follow-up (n = 39, 64%). All 61 biopsied/excised lesions were benign with a PPV and a malignancy rate of 0%. No phyllodes tumors were detected.

The risk of malignancy in young female patients with probably benign (BI-RADS 3) solid masses is very low, with no cancers or phyllodes tumors detected in our cohort. A single 6-month imaging follow-up and then ongoing clinical surveillance may be sufficient in assessing probably benign solid masses in young women under the age of 35 years.