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While each rare cancer individually affects a very small number of patients, rare cancers collectively account for almost 1 in 4 of cancer cases according to EU data.
And yet despite that, research into rare cancers remains very much a minority pursuit, and we face a series of challenges in improving treatment for these patients. In my field of sarcoma research which looks at rare cancers that develop in the muscle, bone, nerves, cartilage, tendons, blood vessels and the fatty and fibrous tissues, we have used the same first-line chemotherapy for patients where the disease has spread for the past 40 years!
There are more than 70 subtypes of sarcoma - many of which are not well understood at all. Even with advances in technology, and leaps forward in cancer treatment generally, developing treatments for such a diverse group of cancers remains challenging.
Despite these challenges, there are already signs of more targeted future therapies for rare cancers.
Advances in treatment
At the Institute of Cancer Research, London, we have led a number of studies into sarcomas including research into the genetic cause of a rare childhood cancer, and possible future ways of treating this using existing cancer drugs.
We have also led trials with our partners at The Royal Marsden NHS Foundation Trust to test the efficacy of the drug cediranib to treat a sarcoma predominantly seen in young adults.
More recently, ICR researchers have discovered a novel mechanism of targeting a rare but aggressive sarcoma affecting predominantly young people. This research will hopefully be translated into the clinic - improving outcomes for these patients.
As part of the International Sarcoma Kindred Study (ISKS), a project led by researchers in Australia, the ICR have also helped us understand the genetic mutations that are linked to increased risk of developing sarcomas.
Studies like this collect genetic data from a diverse range of patients, which is helping us begin to understand the possible link between inherited genetic mutations and the risk of sarcoma. This may also help us to treat these cancers in a more targeted way.
Personalising treatments using patient tumour genetics
A more routine and integrated approach to collecting genetic data in research and healthcare will be key to improving outcomes for patients with rare cancers.
By placing patients in different groups, or sub-types, based on the mutations in their cancers, we can select the targeted treatments that are most likely to work for each person.
Increasingly we are moving towards treating patients according to the particular set of genetic mutations in their cancer, rather than simply on the location of their cancer. But moving fully to such a precise approach to treatment will require significant changes in how we diagnose patients and monitor them during treatment.
You can support the ICR's work to improve treatments for children and young people with sarcoma, an aggressive form of cancer, via our sarcoma appeal page.
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Drug authorities must accept earlier clinical trial data
By analysing the genetics of each cancer, we are also able to conduct smarter, faster, clinical trials.
We can select patients, who because of their cancer genetics, are most likely to respond to a specific drug. We would then expect a higher response rate from those patients selected than in an unselected patient group.
This helps us to gain statistically significant findings from smaller number of patients, which is vital for research into rare cancers, where it is often difficult to recruit patients for large-scale randomised trials.
Smaller, smarter trials not only get treatments to patients faster, but they can also bring down costs a vital consideration for a currently underfunded field of research.
We need to see more adaptive trials into rare cancers, where researchers test a range of treatments for each subtype of cancer at the same time. This could then quickly change a patient's treatment when they are not responding to the current treatment as expected. Researchers can then learn about the effect of a drug in real time, rather than having to wait for the final results of a clinical trial which may take a number of years.
However, for these treatments to reach patients, we need regulatory authorities to accept earlier clinical trial data when appraising drugs for rare cancers, of course without affecting the scientific value of the trials.
Organisations such as the National Institute of Healthcare and Excellence National Institute of Healthcare and Excellence (NICE) and the European Medicines Agency (EMA) are increasingly assessing drugs based on earlier clinical data and we need them to be even more willing to do this where the drug in question is for a rare cancer.
This is vital, as we don’t have sufficient patients to participate in large randomised clinical trials in such rare indications.
Improving pathways to diagnosis
While it's encouraging to see advances in new treatments for rare cancers, there remain substantial problems in delivering healthcare for these patients.
Rare cancers are often diagnosed at a later stage than common cancers, in part because of a lack of expertise in the field. Patients may also have to travel for treatment to the small number of specialist centres. These issues can affect patients in a negative way.
It is important for us to understand what leads to rare cancers being missed in the critical early stages of disease. Several factors can affect the speed of diagnosis, including how likely an individual patient is to report their symptoms, whether unusual symptoms are recognised as a potential cancer diagnosis, and speed of the pathway from the GP through to a relevant clinic.
International study on all aspects of diagnosis
To understand these delays, I am setting up a study across the UK and the Netherlands called QUEST, which is focused on the diagnostic pathway. This study will look at all aspects of diagnosis; comparing and contrasting how the different healthcare systems contribute to patient outcomes.
International studies like this allow us to establish best practice in cancer diagnosis, with countries learning from each other about how best to benefit patients. With such small patient populations, international collaboration will always be needed to research into rare cancers.
Learning how to best structure the diagnostic pathways is equally as important for improving outcomes for patients as working together to develop novel new treatments. Together, these two areas of research can ultimately deliver exciting advances for patients with rare cancers living all over the world.
This blog was written in collaboration with Rare Disease UK for Rare Disease Day 2018.
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