A patient’s response to cancer therapy is as unique and individual as the patient themselves. Therefore, it is extremely important to identify and monitor responses at the individual patient level. This will ensure that treatment is continued for those who are responding well, providing them with reassurance, and, perhaps more importantly, the treatment is adjusted for patients who are not seeing benefit. The latter will reduce unnecessary side effects and allow an early switch to an alternative therapy which will hopefully work more effectively.
Detection of patient response is achieved using biomarkers – characteristics which ‘mark’ the biology of a tumour and can change over time or following treatment. Biomarkers are typically evaluated from patient biopsies; however, these are invasive and often uncomfortable for the patient, cannot be taken at multiple timepoints during the course of treatment, and only provide a small snapshot of what is going on in the whole tumour. Imaging techniques, such as magnetic resonance imaging (MRI), are non-invasive and can provide information about the whole tumour or multiple tumours in the body if the cancer has spread. This information gathered from so called ‘imaging biomarkers’ is related to the underlying tumour biology and can change following successful treatment.
I am a biologist funded by Cancer Research UK and my research aims to use MRI biomarkers to track breast tumour response to treatment over time in a completely non-invasive way. Often breast tumours are first identified by manual palpation to feel a stiff lump. This stiffness is a result of densely packed tumour cells and accumulation of extracellular matrix molecules including collagen and hyaluronic acid. Such molecules can block the delivery of drugs from the bloodstream and provide a scaffold upon which a tumour can grow. A new therapeutic approach aims to decrease the amount of extracellular matrix in a tumour to improve the delivery of drugs such as chemotherapy or immunotherapy.
One promising MRI technique I am currently evaluating is magnetic resonance elastography (MRE) which is essentially virtual palpation because it can measure tumour stiffness. This tumour characteristic is expected to change once these new therapies reduce the build-up of extracellular matrix. MRE can be implemented on conventional MRI scanners, making translation of this research into the clinic relatively quick thus improving patient care.
Before imaging can be used as a stand-alone tool without the need for biopsy, more has to be learnt about how a change in tumour biology affects imaging biomarkers. This research requires knowledge from multiple disciplines, including biology and physics, hence teamwork and communication will be key. The future of cancer research spans far wider than biology. I believe that there are many treatments already out there that will benefit patients with cancer, and as researchers we need to work together with other disciplines to find the right tools to identify the best drug for each and every patient.
By Emma Reeves