Cancer hope as tumour DNA is tracked
Published 29/01/2013 | 05:00
CANCER could become a manageable disease rather than a death sentence, thanks to a revolutionary treatment which will be available within five years.
All patients will soon have their tumours' DNA sequenced, enabling medics to ensure they give exactly the right drugs to keep the disease at bay.
Doctors hope it will be a major step towards transforming cancer from a terminal into a chronic disease.
The technique could enable terminally ill patients – who today can only expect to see out a few months – to live for a decade or more in relatively good health, according to specialists at the Institute of Cancer Research (ICR) in London.
The breakthrough was welcomed by leading Irish cancer specialist Professor John Crown, who said he was hopeful this area of research would bring improvements in cancer treatment. But the St Vincent's Hospital specialist cautioned that the timeline was a little over optimistic.
"We cannot be specific about what cancer research will bring," he told the Irish Independent. However, he said that genetic profiling of tumours had already been successful and he was hopeful of more improvement in the future.
Genetic profiling of tumours is already used to a certain extent, although current methods only look for a few genes.
For example, women with advanced breast cancer are tested to see if their tumours have a particular variant of the HER2
gene, which causes a fifth of cases. Those who have it are given Herceptin, but the remainder are not because it would do them no good.
Professor Alan Ashworth, chief executive of the ICR, said: "We should be aspiring to cure cancer, but for people with advanced disease, it will be a question of managing them better so they survive for much longer – for many years.
"Cancer often appears in people who are old, and if we can keep them alive long enough for them to die of something else, then we are turning cancer into a chronic disease."
Professor Ashworth said the understanding of how different cancers are caused by different genetic triggers is now building "incredibly rapidly".
For example, Vemurafenib is prescribed to half of advanced melanoma patients, who have the BRAF V600 gene mutation.
The pill has been shown to increase survival, on average, from 9.6 to 13.2 months, and help patients feel much more energetic.
While four more months might not sound a lot, such averages hide massive variations. Some patients do not respond at all while others live for years.
One Royal Marsden patient has survived 10 years so far with advanced breast cancer on Herceptin.
Prof Ashworth said such cases were the exception. But he said: "We would hope that they will become the norm."
He added: "None of this is science fiction. One would think in five or 10 years this will be absolutely routine practice for every cancer patient, and that's what we're aiming to bring about."
Prof Ashworth said he thought the method would have "a big impact" on a range of cancers within a decade, but added: "Over the next two to three years, there will be individual patients who receive substantial benefits from these technologies."
Kathy Redmond, editor of the European School of Oncology magazine 'Cancer World', also sounded a note of caution: "So far only a minority of cancer patients have derived significant benefit from targeted drugs, and that is not likely to change much in the immediate future.
"Arguing in favour of putting all our eggs in the 'personalised medicine' basket is, therefore, a flawed strategy that risks creating unrealistic public expectations."
Professor Jane Maher, chief medical officer at Macmillan Cancer Support, said: "The concept in principle is a really exciting one. But technologically there are real challenges in knowing how quickly this will happen."
Tumours were often genetic mosaics, she said, and very good at developing resistance.