A special type of MRI scan called Oxygen-enhanced magnetic resonance imaging (OE-MRI), where patients inhale 100% oxygen, could result in lower radiotherapy doses for some cancer patients.
Using the non-invasive technique, the scientists were able to map parts of tumours that had oxygen deficiency – known as hypoxia – in patients with head and neck cancer. Patients with hypoxia in their tumours respond less well to treatment.
The team say that this technique will enable physicians to target and fine tune treatment more precisely, reducing damage to healthy tissue in some patients.
The study was led by scientists at The University of Manchester and The Institute of Cancer Research, London, funded by Medical Research Council, Cancer Research UK, The National Institute for Health and Care Research, and has been published in Clinical Cancer Research.
The study
Though the study was performed on patients with head and neck cancer, it raises the prospect that OE-MRI could be useful in patients with other cancers.
The oxygen enhanced imaging provides detail similar to an expensive PET scan, but can be performed on standard – and much cheaper – MRI systems.
OE-MRI scans were given to 27 patients of their primary and nodal tumours before they began their standard chemotherapy or radiotherapy treatments and additional scans were then performed during their treatment.
Using sophisticated mathematical modelling, the method was found to have the potential to help patients whose tumours had reduced levels of hypoxia by the second week.
Michael Dubec, principal clinical scientist at The University of Manchester and The Christie NHS Foundation Trust, said: “Cancers can be destroyed by radiation and chemotherapy, but the problem is healthy tissues and organs can destroyed as well. So our aim is to destroy the tumour while preserving healthy tissue thus reducing toxicity.
“Using Oxygen-enhanced magnetic resonance imaging to map hypoxia in patients’ tumours, may improve the accuracy of their treatment. Now we have proved the principle, we hope to move on to clinical trials so it can be validated on greater numbers of patients.”
Professor James O’Connor of The Institute of Cancer Research, London and The University of Manchester led the study, added: “Few studies have compared the hypoxia modification observed in both primary tumour and nodal metastases following treatment, or the timing of these changes.
“So our findings amount to a potentially important way to determine optimum radiotherapy planning for patients with locally advanced disease.”
