Study of Diffusion Weighted MRI as a Predictive Biomarker of Response During Radiotherapy for High and Intermediate Risk Squamous Cell Cancer of the Oropharynx (MeRInO Study)

Around 1000 patients with new cancers of the head and neck (H&N) are registered in Scotland annually. Approximately 60% of these are managed in the west of Scotland. Unfortunately a large proportion, around 60%, of H&N cancers present with locally advanced but non-metastatic disease. These are associated with poor outcomes with 3 year survival around 50%. Despite intensive radical therapy associated with significant acute toxicity, there is a high recurrence rate (up to 50%) and unlike many other cancers, the vast majority of these recurrences, around 80%, occur locally and many patients go on to die from their local disease without developing distant metastases. Locally recurrent tumours cause significant morbidity and palliation is difficult. There is a therefore a clear need to further improve local disease control, both to increase cure rates and to improve quality of life.

This study is designed to assess the value of DW MRI as a predictive biomarker in intermediate and high risk OPSCC. DW MRI and changes in ADC have been shown to correlate with response to treatment in prospective and retrospective studies in SCC H&N. These studies have included all H&N sub-sites with no differentiation between biological sub-types. This study may therefore validate the use of DW MRI as a predictive biomarker specifically in the intermediate and high risk groups of OPSCC. If change in ADC during RT is found to be predictive of eventual clinical outcome and a discriminatory threshold rise in ADC identified, this information could be used to inform treatment intensification in patients responding poorly to RT. This would form the basis of subsequent clinical trials.

The hypothesis of this study is that quantitative DW MRI - i.e. change in ADC during RT - is predictive of locoregional control in intermediate and high risk OPSCC and that a threshold can be identified in ADC change that will discriminate responders from non-responders to radiotherapy.

The design is a single centre observational study to assess the value of DW MRI as a predictive biomarker in HPV-OPSCC. 2 DW MRI scans will be carried out on participants in addition to all standard imaging and procedures for radiotherapy. The information gained from the MRI scans will not be used to change standard treatment for these patients. DW MRI_1 will be obtained prior to radiotherapy commencing. DW MRI_2 will be carried out during the third week of radiotherapy treatment. The DW MRI scans will be used to measure ADC and to calculate change in ADC between the 2 scans. The MRI scans will be carried out during routine hospital visits for radiotherapy planning and treatment therefore will involve no extra visits for participants.

After completion of (chemo) radiotherapy, patients will attend the Beatson WoSCC for follow up visits as per standard protocol at 3, 6, 12, 18 months post treatment. Information regarding recurrence will be collected at these routine visits. No extra post-treatment visits are therefore required from participants.