Lay summary
The incidence of rectal cancer is increasing in NZ, particularly in younger people (< 50 years). Radiotherapy is often used to treat rectal cancer but patients have varying response, and currently, there are no predictive biomarkers of response available. Our recent work has identified an immune signature in rectal tumours that is predictive of response to radiotherapy, and, based on this, we will validate a biomarker test in an international cohort to predict response to radiotherapy and better direct treatment for rectal cancer patients. In addition, we found that the immune signature is linked to a specific tumour microbiome. We will use state-of the art techniques to determine the tumour immune-cell microenvironment that co-operates with radiotherapy and explore the potential of microbiome-based interventions to improve response to radiotherapy. This work will lead to the development of novel tests and microbiome-based treatments for rectal cancer, and ultimately improve outcomes for cancer