Science and Technology
03.07.2013

New breast cancer test will help more women avoid unnecessary chemotherapy

The test, which can be processed locally, indentifies more women with the highest risk of their breast cancer returning,

A new genetic test for one of the most common forms of breast cancer will help doctors better identify those women who should be considered for chemotherapy, and those who can avoid it, say researchers.

A team at The Institute of Cancer Research, London, The Royal Marsden NHS Foundation Trust and Queen Mary University of London found that the test - called PAM50 - produced better long-term information than current methods for determining if a patient' s breast cancer would return.

The test, which can be processed locally instead of being sent off to an American lab, indentifies more women with the highest risk of their breast cancer returning, with fewer women classed as at intermediate risk.

The new test could therefore help doctors identify with greater certainty the women who will have the most potential of benefitting from chemotherapy, while letting others avoid unnecessary treatment.

The research, published today (Monday) in the Journal of Clinical Oncology, was funded by Breakthrough Breast Cancer, AstraZeneca and the NIHR Biomedical Research Centre at The Royal Marsden, with additional support from Cancer Research UK.

Breast cancer is diagnosed in 50,000 women every year, with 80% of cases caused by oestrogen receptor positive (ER+) disease. Women with this type of breast cancer can be treated with hormone therapy, but for some women, the risk of their breast cancer coming back within 10 years means they are also given chemotherapy.

Currently, a test called Oncotype DX (1) can assess the likelihood of a patient' s breast cancer returning, but the test costs more than £2,000 per patient to be administered privately and samples must be sent abroad to be processed. The current test also identifies a large portion of women as having ' intermediate risk' , making a doctor' s decision of whether chemotherapy will help more difficult.

In this study, scientists assessed RNA in tissue samples taken from 940 patients with ER+ breast cancer and compared the new PAM50 score, which analyses 50 genes linked with breast cancer, with the Oncotype DX test, and with a test called IHC4, developed by Breakthrough Breast Cancer.

The PAM50 test provided more long-term predictive information for doctors than both the Oncotype DX test and IHC4, while being as effective as other tests in identifying women at low risk of their breast cancer recurring.

Notably, the PAM50 test categorised more patients as having a high risk of their breast cancer returning within 10 years and fewer as intermediate than the other two tests. The researchers said the PAM50 test could therefore be a more cost-effective tool while providing doctors with more relevant information for determining which breast cancer patients will benefit most from chemotherapy.

Source: CANCER RESEARCH UK