This article was last reviewed on
This article waslast modified on 10 July 2017.

On 7 August 2013 the National Institute for Health and Care Excellence (NICE) published a detailed evaluation of the clinical and cost effectiveness of molecular tests used during breast cancer surgery to detect cancer cells in the ‘sentinel’ lymph nodes in the armpit. Sentinel nodes are those to which breast cancer cells first spread.

About 46,000 cases of breast cancer are diagnosed in England and Wales each year. Current NICE guidance is that patients in whom a mammogram (X-ray of the breast) or an ultrasound scan shows early invasive breast cancer should be offered an ultrasound scan of the armpit. If the lymph nodes appear abnormal, ultrasound-guided needle biopsy is offered to detect cancer cells. If there are no abnormal nodes on ultrasound, or if the biopsy tissue examination is negative, then the breast tumour can be removed with only minimal local surgery. However, in order to confirm that there has been no lymphatic spread in these patients, radioactive material and a blue dye are injected into the breast before the operation to identify sentinel lymph nodes. One or more nodes are removed during the operation and sent to the laboratory for microscopic examination.

This recent NICE evaluation has approved the use of a molecular test, the One-Step Nucleic Acid Amplification system (RD-100i OSNA, Sysmex UK), to examine sentinel nodes while breast tumour surgery is underway. A whole sentinel node is homogenised and the liquid phase analysed in an automated system. The analysis looks for messenger RNA (mRNA) that codes for the production of a protein called cytokeratin-19 (CK19). This mRNA is present in 99% of breast tumour cells but not in normal lymph nodes. The semiquantitative test result for one node is available in 30 minutes and for up to four nodes in 40 minutes. Because sentinel node analysis can be done while the primary tumour is being removed, the total time in surgery may not be significantly increased.

This evaluation concluded that the OSNA system would represent a cost-effective use of NHS resources for those with early invasive breast cancer. It would let the surgeon removing the tumour decide whether all the armpit lymph nodes should also be removed during the same operation, rather than having to wait 5 to 15 days for the results of examination of tissue under a microscope. Such a wait can cause anxiety for patients, and a positive result may lead to a second operation at the same site which can be more difficult, with a higher risk of complications. In addition, the availability of a result during the operation would allow the early start of treatments such as chemotherapy.