The number of women diagnosed with breast cancer who undergo unnecessary chemotherapy could be dramatically reduced following results from medical findings carried out in Ireland, a US cancer diagnostic service claims.
US firm Genomic Health claims the new genomic testing can conclude not only the suitability of chemotherapy but whether or not the treated cancer is likely to recur.
Chemotherapy is a toxic treatment with severe side effects and is only thought to benefit about 4 per cent of those diagnosed with hormone-sensitive early stage breast cancer, according to the company. The test will determine which patients are still likely to need it.
Global “TAILORx” trials carried out between 2007 and 2010 by Genomic Health under the umbrella of the US National Cancer Institute, enrolled 10,273 patients, including 733 from 15 hospitals in Ireland.
Recurrence
According to results due to be announced today of 1,626 patients measuring a low probability of recurrence through the “Oncotype DX” test, 99.3 per cent displayed no new symptoms five years after the original trial.
To date in Ireland, the trial has led to a 58 per cent reduction in chemotherapy use, according to a study carried out by the All Ireland Co-operative Oncology research group in collaboration with the national cancer control programme. This resulted in net cost savings of about €800,000 to the health service.
Steven Shak, founder and chief scientific officer of Genomic Health said: "Ireland was very much ahead of the curve in seeing the value of it. It was the first country in Europe that gave public reimbursement that allowed for access to the citizens."
Genetic trials
The project is among the largest breast cancer research project ever undertaken, and genetic trials are carried out in countries such as Ireland, Canada, Peru and Australia.
Traditionally, the decision on whether or not to use chemotherapy, as well as radiotherapy and hormone treatment, was based on an analysis of the tumour and age of the patient.
“What this [new approach] does is it helps women and their physicians determine whether they need to add chemotherapy,” said Mr Shak.
Genomic Health is undertaking three more similar projects in Ireland, focusing on more cancer types including colon, ductile and another form of breast cancer known as node-positive. Breast cancer is the most commonly diagnosed form of the disease in Irish women, with 2,700 cases every year.
Reassured
Addressing the TAILORx trial, Prof John Crown of St Vincent's University Hospital, who was involved in the trial, said: "The key thing to say here is that clinicians and patients who are worried about not taking chemotherapy when they are in that low risk group need to be ultimately reassured they don't need it. There is no evidence that chemotherapy will make any difference. All they are taking is toxicity; all they are taking is side effects."
