Imagine you’re in a dark room trying to solve a puzzle, but your only source of light is a narrow slit that illuminates just a single piece at a time. That might give some idea what it’s like to look for signs that a cancer has recurred for patients with myeloma, a cancer of the bone marrow.
At the moment, there is no way of knowing if cancer has returned to the bones without taking marrow biopsies. These can easily miss cancerous tissue as you only see small pieces of the puzzle. So how could you illuminate the whole picture? You obviously can’t biopsy someone’s entire skeleton! The holy grail of cancer imaging would be a scanner capable of identifying cancerous tissue across the entire body.
David Collins, Principal Clinical Scientist in the MRI team at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, is close to realising such a goal.
“Using a technology known as diffusion-weighted MRI (DW-MRI), we are developing imaging techniques that could actually give us quantitative measures of tumour burden across the whole body,” he says. “These are now being used on myeloma cancer patients, and we’ve had a lot of interest from clinicians who are keen to apply the technology to a whole range of cancer types.”
Whole-body cancer imaging is an incredibly exciting prospect, and not just for myeloma patients. The Institute of Cancer Research (ICR) is pioneering an approach which looks at the effects of cancer across the entire body, not just in localised tumour sites.
By looking at the patient’s whole body, scientists can even put a figure on the total tumour burden. This is incredibly useful for assessing the full effects of new treatments, since different patients respond in different ways. The Cancer Research UK and EPSRC Cancer Imaging Centre, a facility shared by the ICR and The Royal Marsden, has developed the capability to measure the totality of the disease throughout the body.
“Measuring whole-body disease using magnetic resonance is something we helped to develop here, and my colleague Matthew Blackledge led the charge with his award-winning research,” says David. “We’ve developed a number of sophisticated techniques since then, and are now starting to see real benefits for patients.”
One of the techniques implemented by Collins and the MRI team uses DW-MRI combined with a technology known as ‘fat-water imaging’, which shows the distribution of fat and water throughout the body. This fat-water method is perfect for looking at whether bone cancers have responded to treatment, as he explains: “When cancer invades the bones, it replaces the fatty tissue which you see in healthy marrow. If you treat the cancer successfully, you can actually see fat return to the bones. This is a great sign, as it means the healthy tissue is back and the cancer is gone.”
DW-MRI technology has also been used to develop a measure known as the Apparent Diffusion Coefficient (ADC), which can reveal a lot about the current state of the disease. Researchers can use the ADC to assess how well a treatment has worked, making it an ideal tool for drug development.
These technologies are currently involved in a number of promising trials, where they are being used to image adult populations. While this is great news for adults with myeloma, the disease also affects a minority of children. Imaging children presents unique challenges, such as difficulties getting them to stay still for a scan.
Collins explains: “You can get adults to remain still and hold their breath during a scan so that the motion of their chest doesn’t interfere with the image. With children you simply can’t do that, so we have to develop techniques that are better able to cope with motion.”
The MRI team are using high-speed, high-resolution imaging technologies to overcome the problem of motion, and soon expect to be able to capture clear images during breathing. This could revolutionise paediatric imaging, bringing the full benefits of DW-MRI technology to children with cancer.
Taking breakthroughs from lab to clinic is an important part of Collins’ work, enabling patients to benefit from the fantastic science done at The ICR. He says:
“The radiographers, radiologists and clinicians at The Royal Marsden have all played a vital role in taking the technologies we develop into clinical practice.”
To translate scientific discoveries into clinical solutions, however, you need the right equipment. A new Centre for Cancer imaging (CCI) is currently being built at the ICR, which will house an astounding array of imaging technologies including DW-MRI.
“The new CCI will make an enormous difference to our work,” says David. “Having everything we need under one roof will greatly accelerate the translational aspect of our work, delivering real benefits to patients much sooner.”
David hopes that whole-body scans will soon be available for children and adults alike. This would enable doctors to truly switch on the light and solve the puzzle of myeloma for thousands of patients living in fear of relapse.
Image (c) Brad Montgomery, Creative Commons BY 2.0