Data collection and management The design, conduct, analysis and reporting of the study follow the methodological standards set out in the REporting recommendations for tumour MARKer prognostic studies (REMARK) guidelines. To maintain confidentiality, identifiers were removed from all sources of data and replaced with a unique participant study number assigned at the point of enrolment. Researchers were trained to follow standardised operating procedures to ensure high quality, consistent collection of data. Data were checked and validated, and inconsistencies in clinical data were resolved by revisiting hospital data at source.