Optimising the radiotherapy planning and treatment for anal cancer

Cohort: 10 patients with histologically proven squamous cell carcinoma (SCC) of the anus, presenting to Austin Health for chemo-radiotherapy from June 2015. Observation: for up to 3 years post-radiotherapy. Interventions additional to standard procedures for purpose of study are administered by qualified health professionals and include: Pre-radiotherapy imaging: During standard MRI imaging session – non-standard diffusion weighted MRI (dwMRI) and dynamic contrast enhanced (DCE) MRI scans within Radiology facility. During standard CT simulation session – additional CT scan in prone position within Austin Radiation Oncology. Post-Radiotherapy - 3-4 weeks post completion of radiotherapy - non-standard timepoint for these scans MRI session – including dwMRI and DCE MRI scans within Radiology facility. PET session - PET imaging within Austin Nuclear & Molecular Imaging department. A number of imaging scans are required to map disease for targeting of radiotherapy (RT), including CT, PET and MRI. Each provides slightly different information about the position, shape and composition of the disease that is used by a Radiation Oncologist to define where to target the radiation and how much radiation to deliver. We aim to add an extra, non-standard MRI imaging sequence called a diffusion weighted (dwMRI) scan, to understand the characteristics of the disease and how its use may change the size or shape of the target area so as to ensure complete treatment coverage and improved outcomes from treatment. Additionally, the use of contrast with MRI, dynamic contrast enhanced MRI (DCEMRI) has been shown in other cancer sites to help better identify and show the disease and to show response to treatment, and we wish to verify this in anal cancer. These MRI imaging scans will be performed within a Radiology facility prior to radiotherapy planning as is is standard practice, with an additional Participation in this research will not alter the treatment provided. This will be delivered to the high standards of Austin Health as per standard department protocol. Other than standard procedures, this study will require extra time to enable additional MRI sequences to be completed, and for an additional radiotherapy planning scan in the prone position to be taken, we would estimate this extra time to be approximately 30 minutes for the MRI and planning CT respectively. During the planning process for radiotherapy you will receive two (2) standard CT scans, one with intravenous contrast, to further help define the area for treatment and to allow for an individualised radiotherapy treatment plan to be created. Standard scans are obtained with participants laying on their back, supine. As part of the research, all participants will receive one additional CT scan with participants positioned on their stomach, prone, resulting in a small amount of additional radiation dose.