The RD-100i OSNA system and Metasin test are designed to show whether cancer cells have spread from the breast to lymph nodes in the armpits of people diagnosed with invasive breast cancer. During surgery to remove a breast tumour, they are carried out to help the surgeon decide at the time (rather than having to wait for laboratory results) whether the lymph nodes need to be removed as well. This can avoid the need for a second operation, and also allow treatments such as chemotherapy to be started earlier.
NICE recommends the RD-100i OSNA system as an option for detecting cancer cells in armpit lymph nodes during breast surgery in people with early invasive breast cancer. Although the Metasin test shows promise, NICE does not recommend it for use in routine clinical NHS practice, and recommends that more evidence for the test is needed.