Personalised medicine involves using information about a person’s cancer to help diagnose, treat and find out about how well treatment is working.
Generally, treatment for cancer depends on:
- where in the body it starts
- how big it is at the time of diagnosis
- if it has spread (the stage)
So, everyone with the same type and stage of cancer would have the same treatment. But we know that this one size fits all approach works better for some people than others.
Genes contain coded messages that tell cells how to behave. They control the growth and development of cells. Understanding more about the genetics of a cancer means that we know there are differences in the genes in cancer cells.
Researchers are developing treatments that target those differences. For example, trastuzumab (Herceptin) works on breast cancers that have a lot of a protein called HER2 but not for breast cancers that don’t have this protein.
This is an area that researchers are still working on. Different cancers have different genetic changes and some have more than one change. So, we need a lot more research before everyone will be able to have treatment based on the genetic makeup of their individual cancer.
Is personalised medicine available for me?
Scientists have been looking in detail at the biology of cancer cells. They've found that some cancer cells have particular proteins in the cell and others don’t. Sometimes, cancer cells have far more of a particular protein than healthy cells.
Personalised medicine is at an early stage of development and we are learning more about it. Some people are already benefiting from this approach. Whether it is suitable for you depends on whether:
- scientists have identified particular gene changes for your type of cancer
- there is a test available for that gene change
- there is a treatment that targets the particular gene change
How these new treatments work
Scientists are most interested in cell proteins that work as messengers within and between cancer cells. For example, a particular protein might tell cancer cells to divide so that the cancer grows.
Researchers are now developing drugs to target and block these messenger proteins. The idea is that blocking these proteins will stop cancers from growing and spreading. But the drugs are not suitable for everyone. They only work on cancers that have the protein they target.
Testing and treatments
Doctors need to do very specific tests on cancers to find out which changes there are inside cancer cells. This is a new and developing area. At the moment only a few of these tests are available for a small number of cell changes in certain types of cancer.
Some drugs are already linked to available tests.
Chronic myeloid leukaemia
A gene change called Bcr/Abl is found in most chronic myeloid leukaemias. There is now a test for this. You are likely to respond to a drug called imatinib (Glivec), if your leukaemia cells test positive for Bcr/Abl
A gene change in some lung cancers encourages the cancer cells to grow uncontrollably. This is called the epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutation. Doctors can test for it. If your cancer cells test positive the cancer may respond to drugs called afatinib, erlotinib, and gefitinib.
Some lung cancers have an overactive version of an enzyme called anaplastic lymphoma kinase (ALK). Doctors can test for this, and they call it ALK positive disease. Crizotinib and ceritinib are drugs that only work in cancer cells with have an overactive version of ALK.
Hormones are made naturally in the body. They control the growth and activity of normal cells. These hormones stimulate the growth of some breast cancer cells. Around 7 out of 10 breast cancers (70%) have oestrogen receptors (ER positive). Your doctor checks your cancer cells for these receptors when you are diagnosed.
Tamoxifen works by blocking the oestrogen receptors, so stops oestrogen from telling the cancer cells to grow.
Some bowel cancers have an altered gene called K-RAS. Drugs called cetuximab (Erbitux) and panitumumab (Vectibix) only work on cancers that have the normal version of this gene, which we can now test for.
Does personalised medicine always work?
Unfortunately, we can’t guarantee that any treatment will always be successful. Even when you've had the right tests and your cancer has a particular gene change, a targeted treatment doesn’t always work.
We think this is because there are many very complicated signalling pathways in cells. So, a treatment might not work because there are other changes in the cell we don’t know about, or don’t have a test for yet. Particular combinations of cell changes may interact. For example, we might block one signal that tells cancer cells to grow. But another signalling pathway might then be triggered, so the cells grow anyway.
Stratified medicine means looking at large groups of cancer patients to find ways of predicting which treatments will work on which cancers. It’s one step towards personalised medicine.
James Peach, Director, Cancer Research UK Stratified Medicine programme: Many of the next generation of cancer treatments will only work in people whose cancer is driven by a particular gene or protein.
We need ways to routinely group, or ‘stratify’ patients as part of their treatment. Cancer Research UK’s Stratified Medicine programme aims to help the NHS prepare for this exciting new way of treating cancer, and provide researchers with intelligence about how treatments work
Voiceover: Launched in 2011, Cancer Research UK’s stratified medicine programme will operate from 7 clinical centres and 3 genetic technology centres across the UK.
St James’s University Hospital, in partnership with the University of Leeds, is one of these clinical centres. Here, patients with a range of cancers are asked if they want to take part in the programme. The programme is initially focusing on people with breast, bowel, prostate, lung, and ovarian cancer, and melanoma.
If they agree, a sample of their blood is taken, the DNA extracted, and stored for later analysis. This gives researchers a sample of ‘normal’ DNA as a reference.
After the cancer patient has had surgery or a biopsy, a tissue sample is sent to the hospital’s pathology lab, where it will be specially treated to protect the DNA inside.
The tissue sample is sliced into wafer thin sections, which are rolled up and placed into a plastic tube. Then they are sent off for genetic analysis to the Institute of Cancer Research and the Royal Marsden hospital’s joint laboratory in Sutton – Leeds’s technology partner in the programme.
Here, the DNA is extracted from the sample and then run through powerful DNA sequencing machines to read each tumour’s unique genetic code.
Information about key mutations in the tumour is sent electronically back to Leeds, where it’s linked to the patient’s medical records. This information is also stored in a central database to help guide future research.
Although this won’t influence the way the patient is treated – at least in the short term – the resulting data will be absolutely vital to allow doctors and researchers to improve the way patients are treated in the future. So tomorrow’s cancer patients will benefit from the results of today’s research.
James Peach: It’s absolutely vital that the NHS starts thinking about how genetically stratified treatment will work in practice. Our programme aims to enlist around 9,000 patients to help us make genetic testing a routine part of NHS practice, as well as providing an unprecedented source of data for researchers, to help them beat cancer.
In the first part of the programme (SMP1), researchers collected samples from around 9,000 people with different types of cancer. They looked at the different genetic changes (mutations) in the samples. This information will be used for future research.
This study has led to the next part of the programme, called SMP2. This is testing for genetic changes in non-small cell lung cancer. The people in the study have a small piece of their tumour and a blood sample sent for analysis.
The researchers will look for 28 different genetic mutations. Based on the mutation found, people might be able to take part in the National Lung Matrix trial. Researchers put the people taking part into treatment groups according to gene changes that have been found in their cancer cells. The drugs used are ones the researchers think will be the most successful based on the gene changes.
Cancer Research UK’s Stratified Medicine Programme marks a new era of research into personalised cancer medicine. It’s looking to tailor treatment to groups of patients who share similar faults in their tumours, helping to match the right treatment to the right patient.
A tumour sample will be taken from each patient and tested for a specific set of gene faults. Patients who share the same fault in their tumours will be placed in the same group, or stratified. Our pharmaceutical partners will then provide each group with the drug to target a specific fault in their tumours. As new experimental treatments become available they can be added to the existing trial. And those showing no benefit can be dropped.
We want to ensure each patient gets the best treatment for their type of tumour.
We will find out more about which treatments work with these and other cell changes as we continue with this area of research.
Cancer Research UK is working with the NHS and pharmaceutical and medical companies to develop more tests and make them available in the NHS.