Scientists at The Institute of Cancer Research, London, used an advanced functional imaging technique to visualise how speedily water molecules can move through a tumour – an indirect measure of the proportion of live cells inside the tumour.
The technique could allow doctors to monitor the effectiveness of new treatments called kinase inhibitors, which block key proteins involved in growth and survival. The drugs often kill cells in the middle of a tumour without affecting the overall tumour volume – meaning their effects don’t show up on conventional scans.
Using a technology known as diffusion-weighted magnetic resonance imaging, researchers showed that a kinase inhibitor called selumetinib successfully killed cancer cells in melanoma and colon tumours.
Their results are published in the British Journal of Cancer.
To see when cancer cells have died, the technique is used to measure something called the apparent diffusion coefficient (ADC) of a tumour – measurement of the speed water molecules move through it.
Study leader Dr Mounia Beloueche-Babari, Staff Scientist in the Division of Radiotherapy and Imaging at The Institute of Cancer Research, said: “Sometimes a treatment may kill cancer cells within a tumour, but the overall tumour volume stays the same. In this study, selumetinib killed cells inside the tumours but these didn’t shrink. Looking at the ADC showed us that there were fewer living cancer cells inside the tumour, which we confirmed when we dissected the tumours under a microscope.”
Non-invasive imaging techniques are increasingly being used to evaluate how tumours respond to different treatments, both in lab studies and clinical trials with patients.
Dr Beloueche-Babari added: “The findings are very exciting and we hope to expand on our research by looking at how the ADC changes when tumours develop resistance to selumetinib. This would allow us to assess the value and limitations of the ADC measure, so that it could be properly applied in a clinical context.”