2020 - 2021

Definitions, inclusion criteria and explanations for the 2020 - 2021 trust results

Patient inclusion and data sources

The majority of these results are for patients in England and Wales diagnosed with bowel cancer 1 Apr 2019 – 31 Mar 2020. For the analysis of surgical care, major resections after 31 March 2020 are excluded in order to avoid including patients who might have been affected by the pandemic.

The NBOCA dataset is linked to Hospital Episode Statistics (HES) and Patient Episode Database for Wales (PEDW) at the patient level to obtain further information on patient care and follow-up such as stoma reversal and emergency readmissions in England and Wales.

The dataset also links to Office for National Statistics records for mortality data, the National Radiotherapy Dataset (RTDS) for information on radiotherapy treatment in England, the Systemic Anti-Cancer Therapy database (SACT) for information on chemotherapy treatment in England, and National Cancer Registry (NCRAS) data for England.

Data Quality

Case ascertainment

Number of patients reported to the Audit as a percentage of the number of patients admitted for the first time to the trust/network with a diagnosis of bowel cancer within the audit period according to the 2020 NCRAS data extract in England and PEDW in Wales. This can be larger than 100 if more patients are reported to the Audit than identified in NCRAS/PEDW.

NB. This year it was not possible to use updated NCRAS data to estimate case ascertainment because the gold standard registry data for 2021 was not available at the time of analysis. Case ascertainment for English hospitals should therefore be interpreted with caution as the denominator is based on last year’s NCRAS data.

Data completeness

% of relevant patient group with useable value of data item.

ASA grade

% of patients recorded as having a major resection who have a particular ASA grade recorded, or no ASA recorded.

Management of all patients

Potentially curative patients

Patients electively diagnosed with colon cancer with pre-treatment staging of T2-T4 and no evidence of metastatic disease.

Management of patients having major resection

At least 12 lymph nodes excised (%)

% of colon cancer patients undergoing major resection with a recorded number of lymph nodes, who had at least 12 lymph nodes examined.

Adjuvant chemotherapy

% of patients undergoing major resection for pathological stage III colon cancer and receiving adjuvant chemotherapy between 01 December 2016 and 31 August 2019. These are unadjusted chemotherapy rates. SACT and HES data are used for patients treated in England and PEDW data are used for patients treated in Wales.

Rectal cancer patients

Neo-adjuvant therapy (%)

% of rectal cancer patients having short- or long-course radiotherapy prior to major resection.

Circumferential resection margin: Negative (%)

% of rectal cancer patients undergoing major resection whose CRM is reported to be negative.

Circumferential resection margin: Recorded (%)

% of rectal cancer patients undergoing a major resection who have a recorded CRM.

APER rate (%)

% of patients with rectal cancer undergoing abdominoperineal excision of the rectum and therefore having a permanent stoma this audit year.

APER/Hartmann’s (%)

% of patients whose rectal cancer resection is an abdomino-perineal excision of rectum (APER)/pelvic exenteration/Hartmann’s 1 April 2015 to 30 September 2019.

Compare trust outcomes

Funnel plots display trust risk-adjusted outcomes for 30-day unplanned readmission, 30-day unplanned return to theatre, 90-day mortality, 2-year mortality and 18-month unclosed ileostomy. The funnel regions represent the 95 per cent limit and the 99.8 per cent limit for trusts compared to the national average. Those trusts with results outside the outer (99.8 per cent) limit are considered potential outliers.

Risk adjustment is performed using the seven items listed under Data Quality as well as mode of admission (elective/emergency) and number of co-morbidities according to HES/PEDW, and an interaction between age and distant metastases. Missing values are imputed using Multiple Imputation. The model for two-year mortality additionally includes interactions between follow-up time (0-3 months after surgery vs. 3-24 months after surgery) and all of the risk factors.

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