Women may get 'tailored' cures for breast cancer

Women could avoid unnecessary and harmful breast cancer treatment in future after a ground-breaking study identified 10 distinct types of the disease.

Breast cancer has traditionally been viewed as a single condition with three or four varieties. But Cambridge University academics have pinpointed 10 genetic types of the disease, which should help doctors determine more accurately which treatments stand the best chance of eliminating a particular tumour, and which would be a waste of time.

The discovery, which followed the largest genetic study of breast cancer tissue yet, was hailed by charities as a step towards the "holy grail" of tailoring treatments to the needs of individual patients.

Unnecessary treatment with toxic drugs is a major risk in breast cancer treatment because doctors are unable to determine which patients will respond best to which drugs.

Studies suggest that up to 10 women undergo unnecessary treatment for every one whose life is saved. It is hoped that in future, the quarter of breast cancer sufferers with the least aggressive tumours could be precluded from treatments such as chemotherapy which have ravaging side effects.

Professor Carlos Caldas, who led the study, said: "We are over-treating a significant number of women. We are not doing that because we are evil, we over-treat them because we just cannot precisely define the ones who are going to benefit. If we could identify subgroups where they have such good outcomes that we could spare them treatments instead of adding more and more toxic treatments, that would have enormous value for women."

The discovery could also help drug companies develop new treatments aimed at particular strains more accurately and effectively, he added.

Almost 50,000 women are diagnosed with breast cancer every year in Britain and more than 10,000 deaths are attributed to the disease.

The Cambridge academics studied the DNA of 2,000 tumours and compared it to patients' responses to different treatments and their survival rates. They found that all but a handful of tumours shared one of 10 genetic "signatures" dictating how aggressive they were and how they reacted to treatments.

Prof Caldas said further research into each cancer subtype could lead to doctors developing more accurate diagnostic tests within three to five years.

Dr Harpal Kumar, chief executive of Cancer Research UK, which funded the study, said: "This will, in the years to come, have an enormous impact on the way we think about both diagnosing and then treating women with breast cancer."

Baroness Delyth Morgan, chief executive of the Breast Cancer Campaign, added: "Being able to tailor treatments to the needs of individual patients is considered the holy grail for clinicians and this extensive study brings us a step further to that goal."