12 August 2013
ByAppeared in BioNews 717
The test is designed to be used during initial surgery to remove tumours in patients with early invasive breast cancer. By detecting abnormal genetic markers in the lymph nodes, the test can assess if cancer cells have spread from the breast to the lymph nodes in the armpits, and can help surgeons decide at the time whether the lymph nodes should also be removed.
While many patients currently have to wait up to two weeks after their first operation to find out whether a cancer has spread, the new method will give faster results and may avoid the need for follow-up surgery, reducing the risk of clinical complications. It will also allow treatments such as chemotherapy to be started earlier.
Dr Carole Longson, director of the Centre for Health Technology Evaluation at NICE, said: 'For people with breast cancer and their families, waiting to hear if the disease has spread can cause significant distress and anxiety. If the test is positive, and a second operation is needed to remove more of the axillary lymph nodes, the second operation can be technically more difficult and result in a higher risk of complications'.
Breast cancer is one of the most common cancers in women, with around 46,000 new cases diagnosed in England and Wales each year. It can spread through the circulation or the lymph system, a network of channels and glands called lymph nodes. If cancer cells do detach from the original tumour they are most commonly carried to the axillary lymph nodes in the armpit.
At present patients undergoing cancer surgery usually have one or more lymph nodes removed from their armpit at the same time. The biopsies are sent for laboratory analysis to confirm whether additional surgery to remove the remaining lymph nodes is needed. According to NICE, around 11,000 people with newly diagnosed breast cancer require this additional surgery. However a second operation can be more dangerous as it involves operating on the same area of the breast and armpit as the first.
The new test, called the RD-100i One Step Nucleic Acid Amplification (OSNA) system, involves analysing lymph node samples for the presence of a protein called cytokeratin-19 (CK19), a biological marker associated with breast cancer. Studies have shown to test to be between 77.8 percent and 97.2 percent accurate.
As well as providing results more quickly than conventional biopsies, the test allows the whole lymph node to be analysed therefore likely reducing the risk of missing areas that are too small to be seen using conventional methods.
A similar novel method, the Metasin test, has also been developed. However, although NICE says it 'shows promise', the Metasin test is not currently recommended for use as further evidence of its effectiveness is needed.