'Sing With Us' choirs are an initiative established in Wales by Tenovus Cancer Care to provide social support and improve mental wellbeing amongst those affected by cancer, whether patients, carers or staff. Research has already demonstrated that these choirs can reduce depression and anxiety amongst participants and improve social support networks and quality of life as well as preliminary evidence that they can reduce levels of stress hormones and enhance immune activity 5,6. The aim of this study is to establish more about the psychological benefits of regular choir singing and explore whether the biological changes noted in pilot studies can be sustained over time. This could identify whether choirs have the potential to optimise health in people affected by cancer, helping to put patients in the best position to receive treatment or maintain re mission and supporting those who care for someone with cancer, whether professionally or informally.