Dynamic contrast enhanced magnetic resonance scanning as a predictor of response to accelerated radiotherapy for advanced head and neck cancer

Tumour perfusion has been assessed in patients with advanced head and neck cancer using dynamic contrast enhanced MRI prior to and at completion of accelerated radiotherapy, and related to local tumour control. Sequential MRI scans, at 3 s intervals after intravenous injection of gadolinium using a dynamic scan sequence through a tumour region of interest (ROI), were performed in 13 patients with advanced head and neck cancer before and on completion of radiotherapy. The scans have been analysed in terms of maximum tumour enhancement (E), slope of the enhancement versus time curve and the time taken to reach maximum tumour enhancement (T-max), and these parameters related to tumour outcome after radiotherapy. Local tumour control was related to the value of E on a post-radiotherapy scan and the difference in T-max between a pre- and post-radiotherapy scan. Durable local control was seen in those tumours with a post-radiotherapy value for E of less than 8 and a mean fall in T-max of 27.3 s. These results imply that tumours with diminished tumour perfusion at the end of radiotherapy are those most sensitive to treatment and that those tumours which show greater tumour enhancement after accelerated radiotherapy are likely to fail locally. This may reflect the persistence of viable perfused tumour at completion of radiotherapy.