Comparison Trial of Open-tip Pulsed Needle Biopsy and Conventional Core Biopsy in Axillary Lymph Nodes

It is the standard of care in the United Kingdom for women with suspected or confirmed breast cancer to undergo ultrasound of the ipsilateral axilla prior to surgery in order to detect nodal metastatic disease. Women with invasive breast cancer and normal axillary ultrasound will then undergo operative sentinel lymph node biopsy. This is usually at the same time as the surgical removal of the breast cancer by wide local excision or mastectomy but may be done as a separate procedure before (e.g. where neoadjuvant chemotherapy is planned) or after (e.g. if a non-operative diagnosis of invasive breast cancer was not made prior to surgery). Women who are found to have a positive sentinel lymph node biopsy (i.e. have axillary metastatic disease) normally undergo axillary node clearance (ANC) at a subsequent operation. This policy may change in the future, as evidence from the American Z0011 study suggests that women with low volume axillary metastatic disease do as well with no further axillary surgery plus standard adjuvant treatment as those that undergo ANC.

Women who have abnormal lymph nodes on axillary ultrasound undergo tissue sampling with core needle biopsy (CNB), usually 14 Gauge (14G) under local anaesthetic or with fine needle aspiration cytology (FNAC). Women with proven axillary nodal metastases will then usually undergo axillary node clearance at the same operation as surgical removal of the primary tumour.

The number of women who need to undergo more than one operation can therefore be minimised by maximising the number of women with axillary metastatic disease in whom this diagnosis is made preoperatively.

Meta-analyses of published studies and more recent studies suggest that ultrasound has a sensitivity of ~60% and specificity of ~80% for the detection of metastatic lymph nodes. Although no randomised comparisons of 14G core needle biopsy (CNB) and FNAC have been performed, several studies have suggested that CNB is more accurate. Ultrasound-guided biopsy of nodes subsequently proven at surgery to contain metastases has a sensitivity of ~80% and a specificity of 100% and is more likely to be positive in those women with a higher nodal burden. Numerous studies suggest that increasing the volume of tissue removed may increase the diagnostic yield.

Recently a new biopsy device indicated for the use in breast and axillary lymph nodes (NeoNavia biopsy system, NeoDynamics, Sweden) has become available. It incorporates a pneumatic needle insertion mechanism that is intended to provide better control of needle progression and enable stepwise insertion without noticeable deformation or displacement of surrounding tissue as visualized under ultrasound. Furthermore a new method of tissue acquisition is employed that has pre-clinically shown a significantly higher sampling yield compared to CNB. These characteristics indicate that the device could be well suited for axillary lymph node biopsies. Initial clinical results indicate that in axillary lesions deemed "technically difficult", i.e. where prior US-guided biopsies with CNB or FNA had yielded non-diagnostic histology results, the NeoNavia device performed successfully, thereby significantly altering clinical management.