For more information about NATCAN, the data we use, participation in the audits, and audit reporting, please visit our general FAQs here.
About NBOCA
The National Bowel Cancer Audit (NBOCA) is a mandatory national audit that has been in place since 2010. Its purpose is to measure the quality of care and outcomes for people with bowel cancer in NHS trusts in England and health boards in Wales, with the goal to improve the quality of care provided.
The Audit is commissioned by the Healthcare Quality Improvement Partnership (HQIP), funded by NHS England and the Welsh Government.
The Audit involves a wide range of professionals and organisations that collaborate to ensure its effectiveness. The core group is the NBOCA Project Team, which works in close consultation with its own Clinical Advisory Group and the ACPGBI and a Patient & Public Involvement Forum to integrate expert and patient perspectives.
Beyond these groups, the Audit is a partnership between several organisations; the Healthcare Quality Improvement Partnership (HQIP) commissions the audit, funding is provided by NHS England and the Welsh Government. The National Cancer Audit Collaborating Centre (NATCAN), which is part of the Royal College of Surgeons of England’s Clinical Effectiveness Unit, is responsible for delivering the audit and managing the data.
Methodology and Reporting
The Audit includes all patients with a primary diagnoses of bowel cancer within the current report period.
Included patients are:
1) Aged 18 or older at the date of diagnosis
2) Diagnosed in the audit period
3) Diagnosed with bowel cancer for the first time, with one of the following ICD10 codes:
C18 Malignant neoplasm of colon
C19 Malignant neoplasm of rectosigmoid junction
C20 Malignant neoplasm of rectum
The following patients are excluded from the audit:
• Sarcomas
• Lymphoma
• Neuroendocrine/Carcinoid tumours
• Melanoma
Unless stated, audit metrics are not restricted by route of diagnosis/urgency of surgery i.e. surgical metrics include elective and emergency surgery.
Please see section 3 of the NBOCA SotN Methodology Supplement 2025 for full inclusion/exclusion criteria including OPCS procedure code lists https://www.natcan.org.uk/library/nboca-sotn-methodology-supplement-2025
Please see section 5 of the NBOCA SotN Methodology Supplement 2025 for full information https://www.natcan.org.uk/library/nboca-sotn-methodology-supplement-2025
(Information about how the contextual measures available in the Data Tables are defined is available in Appendix 6 of the Methodology Supplement).
Please see section 7.2 of the NBOCA SotN Methodology Supplement 2025 for full information https://www.natcan.org.uk/library/nboca-sotn-methodology-supplement-2025
If your organisation has unusually low-risk patients compared to all patients nationally, for example they tend to be younger, or have lower performance status, or less advanced cancer, the adjusted outcomes for your organisation will be higher than the observed outcomes. Conversely, if your organisation has unusually high-risk patients compared to all patients nationally, the adjusted outcomes for your organisation will be lower than the observed outcomes.