London: Breast cancer is “not one disease, but 10 different
diseases”, according to a ‘landmark study’ that could
revolutionize its treatment.
An international team of researchers that analysed breast
cancers from 2,000 women said the classifications could help
improve treatment by tailoring drugs for patients’ exact type of
breast cancer and also predict survival more accurately. It will
take at least three more years for the findings to be used in
hospitals, the researchers said.
In the study, published in the journal Nature, the team
analysed genetics of frozen breast cancer samples from 2,000
women at hospitals in the UK and Canada. They looked in huge
detail at the genetics of the tumour cells — which genes had
been mutated, which genes were working in overdrive, which were
being shut down.
They found that all the different ways the cells changed
when cancerous could be grouped into 10 different categories,
named IntClust one to 10. Each tumour within a particular group
shares similar genes and different women with the same type have
similar odds of survival.
“Breast cancer is not one disease, but 10 different
diseases,” lead researcher professor Carlos Caldas, was quoted
as saying by the BBC News.
He added, “Our results will pave the way for doctors in the
future to diagnose the type of breast cancer a woman has, the
types of drugs that will work and those that won’t, in a much
more precise manner than is currently possible.”
At the moment, breast cancers are classified by what they
look like under the microscope and tests for “markers” on the
tumours. Those with “oestrogen receptors” should respond to
hormone therapies, while those with a “Her2 receptor” can be
treated with Herceptin.
The vast majority of breast cancers, over 70%, should
respond to hormone therapies. However, their reaction to
treatment varies wildly. “Some do well, some do horribly.
Clearly we need better classification,” said Caldas.
Dr Harpal Singh, of Cancer Research UK that funded the
study, said, “This study will change the way we look at breast
cancer, it will have an enormous impact in diagnosing and
treating breast cancer.”
He added the charity would begin using the new criteria in
clinical trials it funded. Outside of trials for new cancer
drugs, the new breast cancer rulebook could take some time to
directly benefit patients.