Adaptive Radiotherapy for Head Neck Cancer.

Changes in patient anatomy may occur either from a tumour volume, position or function of a specific organ at risk, or target volume, weight loss or a reduction in postoperative oedema, and may vary between patients. Adaptive radiotherapy aims to correct morphological variations by realizing one or more plans during the treatment course. Imaging is used to detect these variations, thereby deciding on a potential replanning. At present, adaptive radiotherapy for head neck cancer (HNC) mainly deals with treatment response, such as weight loss or tumor shrinkage. Therefore a properly timed repeat CT scan during treatment is a suitable basis for plan adaptation to account for treatment response.