To scan or not to scan: effect of scanning the axilla of all patients undergoing diagnostic breast ultrasound

Breast ultrasonography is a useful modality in patients undergoing diagnostic and screening breast imaging. However, breast ultrasound has a high false positive rate and can be time-consuming to perform.The purpose of this study was to evaluate the clinical impact of incidental axillary findings found on diagnostic breast ultrasounds at a single multi-site institution that has a standard protocol of scanning the axilla for all breast ultrasound exams.All diagnostic breast ultrasounds were retrospectively reviewed from January 2017 to September 2019. Follow-up imaging, relevant clinical history, and pathology results were also reviewed. All positive axillary findings were divided into incidental or non-incidental findings depending on whether there was a direct clinical indication to scan the axilla. Descriptive statistics were performed with a 5% level of significance.Of the 19,695 diagnostic ultrasounds performed during this timeframe, there were 91 (0.5%) incidental axillary findings given a BIRADS category 3 or 4, and none of these findings resulted in the diagnosis of an occult breast cancer. One biopsy-proven SLL/CLL lymphoma was diagnosed that was otherwise clinically occult.Routine axillary scanning in all patients undergoing a diagnostic breast ultrasound at a large multi-site institution yields a low rate of incidental findings and has minimal impact on detection of cancer.