Thursday August 8 2013
The new test should help avoid lengthy waits for results
"Instant breast cancer test approved that will save women weeks of waiting for results," reports the Daily Mirror, while the Daily Mail points out that the test could "spare thousands of sufferers the ordeal of repeat surgery".
The test in question is called RD-100i OSNA, and is used during surgery to remove invasive breast cancer. This new test can tell doctors whether the cancer has spread to the lymph nodes. It does this by detecting abnormal genetic markers in samples taken from the lymph nodes. The test is expected to provide much faster results than conventional biopsies.
The test has now been recommended by the National Institute for Health and Care Excellence (NICE), which advises which treatments should be available on the NHS. It is expected to be introduced for patients selected to have surgery for early breast cancer. NICE says that the test can help avoid further operations and allow treatments such as chemotherapy to begin much earlier.
How does the new test work?
Breast cancer can spread directly into surrounding tissue or through the bloodstream. However, it most commonly spreads through the lymph system.
The lymph system is made up of a network of vessels (channels) and glands called lymph nodes. Breast cancer most often first spreads to the lymph nodes in the armpits (axillary lymph nodes).
Currently, during surgery to remove a breast tumour the patient usually has one or more lymph nodes from the armpit removed at the same time. These are then sent to a laboratory for analysis.
The newly approved test, called RD-100i OSNA system, is a kind of biopsy that examines the genetic material of the lymph node for the presence of biological markers that indicate that the cancer has spread.
The new test looks at the lymph node DNA to detect "gene expression" for cytokeratin-19 (CK19), a protein (or marker) associated with breast cancer. Gene expression is the process through which the information encoded in our genes is used to produce proteins.
Measuring the level of gene expression shows how active the gene is. The results are available immediately, allowing surgeons to remove more tissue from the lymph nodes if the results suggest that the cancer has spread.
NICE says the test can be used to analyse the whole lymph node, reducing the risk of missing areas that are too small to be seen. This may help reduce the need for subsequent operations.
What advantages does the RD-100i OSNA test have over current diagnostic methods?
At present, lymph node tissue is usually sent for analysis under a microscope. It can take up to 15 days for laboratory results to be available, meaning patients have to wait for the results not knowing whether their initial operation has been successful or not, or if they need more surgery.
NICE says that each year about 11,000 patients with breast cancer need this extra operation to manage the spread of breast cancer. Waiting to hear if the disease has spread and if further surgery is needed causes distress and anxiety.
If a second operation is needed to remove more lymph nodes, it can be technically more difficult and result in a higher risk of complications because it involves operating in the same area as the original surgery. For example, surgery can cause damage or disruption to the lymphatic system and trigger a condition called lymphoedema, which causes swelling in the arms and legs.
Because the new test results are available immediately, the surgeon can decide whether other lymph nodes should be removed during the initial operation to help prevent further spread. As well as avoiding a second operation, this also means that other treatments such as chemotherapy can be started sooner.
What has NICE said about who should have the test?
NICE recommends the test as an option for detecting cancer cells in the armpit lymph nodes in patients with early invasive breast cancer.
Early breast cancer means the cancer is not thought to have spread beyond the breast or the lymph nodes in the armpit on the same side of the body.
How reliable is the instant breast cancer test and are there any risks?
NICE carried out a systematic review of the evidence to work out how well the test performs and how effective it is. NICE considered the test's accuracy, failure rate, effect on patient anxiety and clinical effectiveness. The studies gave a range of accuracy between 77.8% and 97.2%.
The organisation says there is a small risk of a false negative result from the test, where the test gives an "all-clear" result even though there are still cancerous cells present.
This is because in a very small proportion of breast tumours there is no gene expression for CK19, so even if the cancer has spread to the lymph nodes this test would not detect it. The manufacturer of the test estimates that this is the case for 1 in 100 breast tumours.
NICE suggests that when a breast tumour is set to be removed, a biopsy sample of the tumour should be pre-screened for CK19 gene expression. If the tumour cells are found to have no CK19 gene expression, the RD-100i OSNA test would not be used on the lymph nodes as this could result in a false negative test result.
This new test should lead to prompter treatment of invasive breast cancer. However, it remains important that women – and men – are vigilant for any abnormal signs and symptoms that could be caused by the initial stages of cancer.
See your GP if you notice any of the following:
- a lump or area of thickened tissue in either breast
- a change in the size or shape of one or both breasts
- discharge from the nipples (which may be streaked with blood)
- a lump or swelling in your armpits
- dimpling on the skin of your breasts
- a rash on or around your nipples
- a change in the appearance of your nipples, such as becoming sunken into your breast
- pain in either of your breasts or armpits not related to your period
Get answers to common questions about NHS breast cancer screening.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.