British scientists say women who develop breast cancer because of two common genetic mutations could have their treatment transformed by a chemotherapy drug which already exists.
The drug Carboplatin which is currently used to treat ovarian and lung cancers may very well be as much as 20 times more effective than standard therapies for breast tumours triggered by defects in the BRCA1 and BRCA2 genes.
The scientists say that animal studies have indicated that Carboplatin,a platinum-based drug not normally used in breast cancer treatment, can target the "Achilles' heel" of tumours caused by BRCA defects.
They say their research with mice has shown that cancer cells with BRCA2 mutations are twenty times more sensitive than normal to Carboplatin, and that BRCA1 tumours are between five and twenty times more sensitive.
As many as 85 per cent of women who inherit mutations in one of these genes will develop breast cancer by the age of 70, and between them they account for 5 per cent of the 41,700 cases diagnosed in Britain each year which occur in women with a strong family history of the disease.
Some groups have a higher risk of having faults in these genes; around one in 44 Ashkenazi Jews carry a change in their BRCA genes compared to less than one in 100 people in the non-Jewish population.
Despite improvements in detection and treatment of early breast cancer, around 25% of women are likely to have a recurrence of their cancer.
The team are presently recruiting 150 BRCA breast cancer patients, 75 with each mutation, who will be treated with Carboplatin or Docetaxel, the standard chemotherapy agent for the disease, to determine which is more effective.
Women who have been diagnosed with a faulty BRCA1 or 2 gene and whose breast cancer has returned elsewhere in the body will be eligible.
Women from the UK, Europe, America and Australia will take part in the four year study.
They will be treated with Carboplatin or the best current treatment, the chemotherapy drug, Docetaxel.
Clinical trials are already under way and should they indicate that Carboplatin performs the same in the women as in the mice, it could be given routinely to breast cancer patients with BRCA mutations within five years.
Andrew Tutt, consultant oncologist at Guy's and St Thomas' NHS Foundation Trust in London, who is leading the trial, says breast cancer is not just one disease and different types of tumour will respond differently to particular drugs.
He says the genetically tailored chemotherapy treatment acts in a much more focused manner than standard chemotherapy.