This guideline covers identifying children, young people and adults with symptoms that could be caused by cancer. It outlines appropriate investigations in primary care, and selection of people to refer for a specialist opinion. It aims to help people understand what to expect if they have symptoms that may suggest cancer. We have used the terms 'men' and 'women' in some recommendations on gender-related cancers, but they also apply to people who have changed or are in the process of changing gender, and who retain the relevant organs.