Breast cancer has always been considered to have three or four varieties, but researchers have conducted a study and now they are sure that it can be separated into ten distinct types which give patients dramatically varying chances of survival.
Knowing which category a patient’s cancer falls into will help to choose the most appropriate treatment and to stand the best chance of eliminating the tumour, and avoid those least likely to benefit the patient.
The Department of Health and Cancer Research UK are due to publish a review of the breast cancer screening program later this year after the scientists suggested that up to 10 women undergo unnecessary treatment for every one whose life is saved, writes The Telegraph.
Prof Carlos Caldas, who led the study, explained: “We are overtreating a significant number of women. We are not doing that because we are evil, we overtreat them because we just cannot precisely define the ones who are going to benefit.”
He kept on: “If we could identify sub groups 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.”
Studying how each tumour type reacts to different therapies is believed to help drug companies develop new treatments which could target particular strains more accurately and effectively.
The statistics show that almost 50,000 women are diagnosed with breast cancer every year in Britain, with more than 10,000 deaths attributed to the disease annually.
The Cambridge University academics examined the DNA of 2,000 breast cancer tumours and compared it against patients’ responses to different treatments and their survival rates.
They found that all but a handful of the tumours shared one of ten genetic “signatures” which dictated how aggressive they were and how they reacted to different forms of treatment.
Prof Caldas predicts that the new information would be useful in targeting clinical trials at select groups of patients, but that within three to five years doctors could start developing more accurate diagnostic tests.
He said: “There will not be a test available tomorrow to a patient coming into a clinic. What this provides us with is a new map of breast cancer that will help us in the path ahead for clinical trials. It will lead to better and more targeted treatments and the benefit of that will take years to be fulfilled.”
Dr Harpal Kumar, chief executive of Cancer Research UK, which funded the study, added: “One of the things people have struggled with is really getting to grips with the reasons why some women respond to treatments and some women don’t.”
Dr Kumar continued: “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, said: “Being able to tailor treatments to the needs of individual patients is considered the holy grail for clinicians and this extensive study brings us another step further to that goal.”