With the development of new genomic tests for breast cancer the whole emphasis for classifying breast cancers has shifted from traditional descriptive, or 'grade' classifications to genomic tests that predict the tumour capacity for 'cell proliferation'. Following surgery to remove the tumour, the breast cancer multi-disciplinary team (MDT) need to make decisions concerning the next most appropriate treatment options. Underpinning this decision is the ability to forecast the likelihood of the cancer recurring and / or forming metastases. The traditional 'grade' classifications are no longer sufficient on their own to fully inform this process. The latest genomic tests, combined with traditional pathology provide a far more accurate assessment. 
Breast cancer expert, Mr Simon Marsh, in his article Why do Patients with Breast Cancer need Gene Testing, describes the latest molecular approach to classifying breast cancers, and why this personalised medicine is good news for women. He says, "This classification not only involves the oestrogen and progesterone receptors (ER and PR) but also the sensitivity of a cancer to the Herceptin drug (Her2) and the Ki67. This is a proliferation index that indicates how fast a cancer is growing and is more sensitive than the “grade” that is often still given.
However, the accuracy of the gene testing arrays and tests available now to patients and their doctors is also advancing rapidly - and usually the speed of science outstrips the ability of regulatory authorities to respond, despite the scientific validation.
Following NICE approval the NHS has approved the use of a breast cancer screening system known as Oncotype DX, however, many breast experts believe that the benefits of this test have been surpassed by the new Endopredict test, which is currently only available in the private sector.
The main advantages of Endopredict are that the test can prevent unnecessary chemotherapy in up to 50% of patients, some of whom are node positive (Oncotype DX will not pick these up). Patient tissue samples do not have to be transported to a specialist laboratory in the US, and so turnaround time is improved and the Endopredict test costs around £1,000 less per sample. The Oncotype DX costs around £2,500 per sample. It is therefore no wonder that the private medical insurers are also likely to approve the use of Endopredict in favour of Oncotype DX, especially if it means that patients will receive better care.
