Colorectal cancer – 1 year survival rate for colorectal surgery for cancer

Metric

Adjusted 1 year survival rates for colorectal surgery for cancer.

NB This will be presented as adjusted survival rates but will be calculated as adjusted death rates and simply reversed for presentation

Numerator

Deaths in or out of hospital between -1 and 365 days inclusive, for any cause, after the index operation date (or admission date if missing); the ONS date of death will be used and can be a day before the date of discharge for patients dying in hospital, for administrative reasons.

Denominator

Any inpatient having a colorectal excision procedure of one of the following OPCS codes:

• H04 Total excision of colon and rectum
• H05 Total excision of colon
• H06 Extended excision of right hemicolon
• H07 Other excision of right hemicolon
• H08 Excision of transverse colon
• H09 Excision of left hemicolon
• H10 Excision of sigmoid colon
• H11 Other excision of colon
• H13 Bypass of colon
• H15 Other exteriorisation of colon
• H29 Subtotal excision of colon
• H33 Excision of retum

 Equivalent to “Excision of colon and/or rectum” procedure group in the DFI tools

And a primary diagnosis of one of the following ICD10 codes:

• C18 Malignant neoplasm of colon
• C19 Malignant neoplasm of rectosigmoid junction
• C20 Malignant neoplasm of rectum
• C218 Malignant neoplasm, overlapping lesion of rectum, anus and anal canal

If they had more than one such admission during the time period of interest, then their first will be taken. Patients are excluded if they have had a similar admission in the previous three full years (i.e. 3×365 days before the index admission date)

Exclusions

• Surgical subgroups 3, 6, 7 and 8 will be excluded. The denominator procedure group “Excision of colon and/or rectum” will be organised into eight subgroups within the DFI tools and for the purposes of risk adjustment; see Notes below for details.
• Those receiving palliative care (if any episode in the spell has the treatment function code 315 or contains ICD10 code Z515 in any of the diagnoses fields)

Data Source

Linked HES-ONS

Time frame

April 2007 – March 2008 (to allow one-year follow-up with ONS data)

Basis

Acute Trust

Statistical methods used

Adjust for the following factors using logistic regression:

• age group
• sex
• emergency admission
• deprivation
• surgery subgroup (relating to involvement of rectum and local lymph nodes)
• Charlson score (also with interaction term with age if significant)
• number of emergency admissions in prior 12 months
• source of admission

Include provider as factor in the model to obtain provider-specific odds ratios (parameterise so that each but one is compared with the national average; the log odds ratio for the omitted one is obtained by summing the log odds ratios for all the others)

Multiply provider-specific odds ratios by overall (national) odds of death to get adjusted odds for each provider

Convert these adjusted odds of death into adjusted survival rates

Bring the 95% CIs from the regression and convert them in the same way as the odds ratios.

Notes

ICD10 contains no TNM staging information therefore we have tried to reproduce the essence using primary and secondary diagnosis fields. ‘Local spread’ requires the presence of a code for a local lymph node AND the absence of codes for distant nodes or organs. ‘Distant spread’ requires the presence of a code for distant nodes or organs (there may also be codes for local node or organ involvement present).

The denominator procedure group “Excision of colon and/or rectum” will be organised into the following procedure subgroups within the DFI tools and for the purposes of risk adjustment. This indicator is excludes subgroups 3, 6, 7 and 8.

1. Colon, no spread
2. Colon, local spread
3. Colon, distant spread
4. Rectum with or without colon, no spread
5. Rectum with or without colon, local spread
6. Rectum with or without colon, distant spread
7. Carcinoma in situ or cancer not originating in colon or rectum)
8. Other diseases (not cancer)

Subgroup title	Primary diagnosis codes	Secondary diagnosis codes
1. Colon, no spread	C18	Any other than C19, C20, C218, C77-C79, D011, D012 (ca in situ in rectosigmoid junction or rectum)
2. Colon, local spread	C18	Any of: C772 (intra-abdominal nodes) and no other C77-C79; C19, C20 or C218; D011, D012
3. Colon, distant spread	C18	Any of: C77-C79 excl C772
4. Rectum with or without colon, no spread	C19 or C20 or C218	No C77-C79
5. Rectum with or without colon, local spread	C19 or C20 or C218	Any of: C775 (intrapelvic nodes) if no other C77-C79; C772 and no other C77-C79 if C19 is the primary dx
6. Rectum with or without colon, distant spread	C19 or C20 or C218	C77-C79 excl C772 if colon is also involved (i.e. primary diagnosis = C19) and also excl C775 if cancer confirmed to rectum (i.e. primary diagnosis = C20 or C218)
7. Carcinoma in situ or cancer not originating in colon or rectum	C00-C99 other than C18, C19, C20, C218; D00-D09 (carcinoma in situ)	Any
8. Other diseases (not cancer)	Any other than C and D00-D09	Any