Genomic medicine for secondary breast cancer: hype or reality?
For some, it’s the next great step forward in secondary breast cancer treatment. For others, the benefits simply aren’t clear enough.
In a hospital clinic, somewhere in the UK, someone awaits the news they never want to hear. “I’m afraid your cancer has returned, and it has spread. The best thing we can do is start treatment right away”.
Unfortunately, this is an all too familiar scene for the thousands of people currently living with secondary breast cancer, and one that can feel like a death sentence. For many of these patients, treatments are ineffective, toxic and in many cases, only serve to extend life rather than cure their disease.
The only reassuring part of the news is that there are treatments available. Chemotherapy is the weapon of choice against most secondary cancers, but using it can be like trying to hit a bullseye with a shotgun. For all the guidance and evidence there is for picking the best drug, or combination of drugs, to treat primary cancers, doctors still don’t really know what the best practice is for treating secondary breast cancer patients and they often rely on their own clinical experience to guide their decision.
Treating the untreatable
There is hope that advances in our understanding and analysis of the DNA code will lead to new ways to treat the untreatable. The era of the £1,000 genome (the complete DNA code of a person) is upon us and everyone is awaiting the shakeup it will have.
The relatively low cost and speed of decoding a patient’s DNA could now allow doctors to analyze a patient’s secondary tumor, identify its genetic weaknesses that are targetable with drugs (so-called targeted treatments), and treat that patient accordingly.
This is the blueprint for personalized medicine and it might offer the best chance of saving lives. The question is - are we ready for it? And is this sort of medicine a reality for patients with secondary breast cancer, or is it just hype?
When researchers talk about the issue it soon becomes obvious that whilst we have the technology and the capability to carry out this sort of DNA decoding (known as DNA sequencing) in the clinic, we should be careful not to get ahead of ourselves.
We should speak about this issue in related conferences because the reality is that there are many complex issues such as the number and availability of using targeted treatments which could prevent this information having any actual benefit for the patient.
A study published this year by researchers that they tested the feasibility of using DNA sequencing to direct treatment of secondary breast cancer patients. They found that 195 of the 423 patients enrolled on the trial had a genetic weakness in their cancer, detected by DNA sequencing, which could potentially be targeted with a specific treatment. Out of these patients, only 23 (five percent) received any treatment they wouldn’t have had normally, and only 13 (3 percent) received any clinical benefit from the different treatment.
But to some researchers, the fact that any of the patients benefitted from this sort of personalized approach marks the beginning of this sort of approach to treatment.
DNA sequencing has vastly improved our understanding of the genetics of cancer and the fact that we can use this technology in clinical setting shows how far we’ve come since the completion of the Human Genome Project. This technology needs to be nurtured alongside basic research to develop the drugs that match the targets we discover through sequencing.
We have made progress with how we treat secondary breast cancer but we need to do more. The survival time of two-three years hasn’t changed for the past two decades.
Key Words: Breast Cancer Genomics, Chemotherapy, DNA Sequencing
ENDS
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