Timing of breast biopsy and axillary ultrasound does not affect the false positive rate of the axillary ultrasound

Background

The determination of axillary lymph node metastases is an important component of breast cancer treatment planning. Lymph node biopsies can be performed simultaneously with breast biopsy or at a later time. However, a post-breast biopsy ultrasound of the axilla may appear abnormal due to reactivity in the axillary lymph nodes. This study examined the timing of the axillary ultrasound (AUS) in relation to a breast biopsy to determine if it would affect patient management.

Methods

All newly diagnosed breast cancers from 2016 to 2017 were analyzed. We analyzed the timing of breast abnormality diagnosis, breast ultrasound, breast biopsy, AUS, and the AUS biopsy (AUSBx). An interval AUS was considered one that was not performed on the same day as a breast biopsy. True positive (TP), false positive (FP), true negative (TN), and false negative (FN) values were calculated. Chi-square analysis and Fisher exact test were performed on categorical data, and a student’s t-test was performed for continuous variables. Significance was determined to be p < 0.05.

Results

Same-day TP and FP AUS rates were 66.5 % and 33.5 %, respectively, and interval TP and FP AUS rates were 60.1 % and 39.9 %, respectively (p = 0.4708). The same-day TN and FN AUS rates were 90.6 % and 9.4 %, respectively, and interval TN and FN rates were 82.4 % and 17.6 %, respectively (p = 0.3917).

Conclusion

Overall TP, FP, TN, and FN rates did not differ between patients who received same-day or interval AUS studies.