National rectal cancer intensity-modulated radiotherapy (IMRT) guidance

With the use of intensity-modulated radiotherapy (IMRT) for rectal cancer increasing globally, this document provides practical guidance on the use of IMRT/VMAT radiotherapy for rectal cancer in the UK.

The guidance addresses the multiple considerations when introducing routine IMRT. These include:

• Considerations for pre-treatment investigations
• Patient preparation
• Optimal delineation of gross tumour volume (GTV)/clinical target volume (CTV)/planning target volume (PTV)
• Provision of a standard atlas for delineation of lymph nodes
• Strategies for delivery of a simultaneous integrated boost (SIB), IMRT planning and patient set-up and treatment verification.