After a breast cancer and any lymph glands have been surgically removed, further (adjuvant) treatment is generally given to reduce the risk of cancer recurrence. For patients with estrogen receptor (ER) positive breast cancer, this treatment has traditionally been chemotherapy and hormone therapy. However, it is increasingly recognised that tumours which are ER positive and negative for the human epidermal growth factor receptor 2 (HER2), are relatively resistant to chemotherapy. It is likely that many more people are exposed to the risks for chemotherapy than ever benefit from it. In order to select patients who will get more benefit from chemotherapy and to spare those who get very little benefit from side effects, risk assessment tools are being developed.
The 21 Gene Recurrence Score is a test that examines the tumour genes to estimate the risk of the tumour relapsing and possible chemotherapy benefits. Currently, the 21 Gene Recurrence Score (OncotypeDx®) is used In Ireland for patients with no cancer in their lymph nodes. For these patients it can help in deciding who should get chemotherapy. Patients with low scores can sometimes avoid chemotherapy. In some countries, this test is offered to almost all patients with ER positive breast cancer, irrespective of whether the cancer has spread to lymph nodes or not. However, in Ireland this test is not standardly available for patients who have breast cancer involving lymph nodes.
