No cure for cancer; just cures

The cure for cancer, often hailed as the holy grail of medical research; something everyone is searching for and no one is finding, doesn’t actually exist.

The idea that someone in a lab someday would find a single cure for all cancer belies the complexity of the large group of diseases that we refer to collectively as cancer.

The Oxford English Dictionary defines cancer as “A disease caused by an uncontrolled division of abnormal cells in a part of the body.” This description is so generic because of the diversity found in the more than 100 diseases that are labelled ‘cancer’.

As there is no one thing called cancer, there cannot be just one cure. What scientific and clinical researchers are actually trying to do is find many cures for many cancers.

One of the tools we use is patient stratification. When we set up clinical trials for new treatments, we establish a strict list of eligibility criteria. These can be anything from smoker status, or even age. Having narrowed down the patient population, we then group individuals even further into groups or ‘cohorts’ for treatment, to try and identify how best to help patients with certain characteristics. This is often done on the basis of a disease characteristic called a biomarker – a chemical signature related to the differences between cancers.

This stratification is a relatively new way of testing potential medicines in humans. In the past, people were diagnosed with cancer in an organ or tissue, for example, breast cancer. These people were all treated in the same way, with highly variable, often poor, outcomes. By separating people into groups by how advanced their cancer is; the presence or absence of certain biomarkers; their other medical history and so on, we are able to work out who fares the best on a specific treatment and what makes that the case.

This is useful information in two main ways. It can help us to develop medicines in the knowledge that they will most likely help patients with a certain type of cancer at a certain stage, or those who have tested positive for a certain genetic mutation. At the same time, we learn that giving this treatment to someone in a different subset of patients may not be beneficial, and as cancer therapies often have quite unpleasant side-effects, people are spared a course of treatment that has little chance of helping them.

This strategy of stratifying patients into these sub groups will help us make swifter progress towards a more patient-centric individualistic approach to the treatment of cancer.