Making personalised medicine for cancer a reality

Judith Potts appeared in the Telegraph today discussing the future of cancer treatments.  Her article, on defining cancer by its molecular attributes as opposed to region in the body, highlights where research should be going.

It’s becoming clearer to scientists that lumping cancers as ‘breast’, ‘ovarian’ or ‘lung’ may not be useful when it comes to treating a patient.  Within each type of cancer there are many sub-types, which are all categorised depending on their molecular, genetic and physical characteristics.  But there is overlap between sub-types of one cancer, which blurs the boundaries that define them.  Cancers can also change during progression of the disease, masking their categorised features and developing new ones.

Cancers are also individual.  Tumours derive from the patient’s own cells and so each cancer is individually characterised by the genetic and environmental factors that have influenced that person’s life.   We know that certain genetic mutations are more likely to occur in certain cancers but the individuality of cancer means we can’t expect a blanket treatment for all patients with one type of cancer.

Judith proposes that molecular profiling for individual cancer patients is the way forward, and I am inclined to agree.  This method looks at a wide range of molecular markers that each represents a particular weakness in the cancer.  A clinician could then use this information to match up each weakness with a drug to exploit it.  This would be done on data gathered from a tumour of an individual patient, providing a clear road towards fully personalised medicine.  Clinicians could also get around the evolving cancer problem by taking new molecular profiles from the patient at different points in their disease and adapting their treatment accordingly.

This type of care for cancer patients is already available in some countries, if you can afford it, but there will be several problems to overcome when the technology becomes widespread.  Biotech companies that patent molecular profiling kits could increase costs.  Confidentiality around their product could also hide whether or not the molecular profiles are accurate.  This could lead to patients receiving an ineffective treatment or a treatment that causes harm.

There is also the issue that drugs approved for use for say lung cancer, may not have been tested against breast cancer.  Molecular profiling might tell you that a patient’s cancer has a weakness for that drug, but you would struggle to be able to give it to them.  And what about new experimental drugs?  With no evidence from clinical trials it wouldn’t be possible to use one even if you knew that the patients cancer would be sensitive to the treatment.  One way around this would be to reassess how clinical trials are set up and allow for greater flexibility in trial design (a discussion for another time).

Molecular profiling is on the horizon and offers obvious benefits to the way we treat cancer.   However, for it to work, the policy and healthcare system needs to evolve with the science.

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