Table 2.

Variables of interest for cases and controls

Patient characteristics	Primary CRA & CRC pathology variables 2	Screening variables 3
Patient unique ID	Tumour unique ID	Screening Health Authority cipher (NHAIS)
NHS number	Tumour status	Screening office code
Sex	Tumour description	Screening office reference
Case or control	ICD-10 code	Year of first invitation to bowel cancer screening
	• C18 - Colon
	• C19 - Rectosigmoid junction
	• C20 - Rectum
Date of birth	Dates of diagnoses (all CRAs & CRCs)	For bowel/cervical/breast screening
Patient status (Alive or dead at end of study period)1	Tumour detection mode (all CRAs & CRCs)	Episode number
Date of death (where applicable)	Anatomical subsite (all CRAs & CRCs)	Episode type
Age at death (where applicable)	CRC Dukes' stage (& any subsequent restaging)	Episode date
Date of index tumour diagnosis	CRA villousness	Screen date
Age at index tumour diagnosis	Tumour size (all CRAs & CRCs)	End code
Died of primary CRC (where applicable)	Treatment/procedure at diagnosis (all CRAs & CRCs)	Flag: NHS or Screening Programme registration by age 60
Cancer registry	Any further treatment/procedure (all CRAs & CRCs)
Geographical area (as available in NCDR)	Optional: Dates of treatment (all CRAs & CRCs)
IMD quintile (or postcode)
Ethnicity

¹For cases and controls who died after date of index diagnosis of the case.

²Those variables will be retrieved for each neoplasia occurrence.

³All screening history.