11th April 2024

Investigations

Ultrasound, mammography and MRI are used in the assessment of breast lesions. The imaging results will identify which lesions should undergo biopsy. The British Society of Breast Radiologists (BSBR) have a standardised classification system for breast lesions. A five-point scale is used to classify lesions from normal (1) to highly suspicious for malignancy (5). The breast imaging-reporting and data system (BI-RADS) is another classification system widely used in North America and Europe. A biopsy is recommended for all suspicious lesions (BSBR/BI-RADS 4 or 5). Biopsy under ultrasound guidance is preferred over alternative imaging modalities. A marker clip should be placed to assist with post-biopsy management (including repeat imaging). 

There are three biopsy methods: FNA, CNB and surgical biopsy. CNB is the preferred initial method in most cases. The benefit of CNB is that it is minimally invasive and usually acquires enough tissue to adequately assess the intended lesion. FNA demonstrates higher rates of insufficient tissue samples and false negative results. In these cases, CNB is required (following FNA). Surgical biopsy is performed if needle biopsy is not technically possible or the results of needle biopsy are inconclusive or discordant. The entire lesion can be removed (excisional biopsy), or a portion of the lesion can be removed (incisional biopsy). 

Complications of CNB include haematomas, infection, pneumothorax, fistula formation and potential seeding of tumour along the biopsy track.