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Methodology 6.12.a

Cervical Screening Follow-up Methodology
Short description of Indicator ​Percentage of Ontario screen-eligible women with a high-grade cervical dysplasia on a Pap test, 21-69 years old, who underwent colposcopy or definitive treatment within 6 months of the high-grade abnormal screen date​
Rationale for measurement

​​Time to colposcopy or definitive treatment is a measure of system capacity and timely follow-up. (1,2) Even if follow-up is ultimately negative, an abnormal screen can cause anxiety, and excessive delays to diagnosis may worsen prognosis. (1)

Ontario’s colposcopy standards recommend colposcopic follow-up within eight to 12 weeks for women with less severe dysplasias. (3)  The Society of Obstetricians and Gynaecologists of Canada recommends that women with ACS-H or AGC should receive colposcopic follow-up within 6 weeks of referral, while women with HSIL should receive colposcopic follow-up within 4 weeks of referral. (4)

Evidence/references for rationale
  1. ​Public Health Agency of Canada (2009).   Report from the Screening Performance Indicators Working Group, Cervical Cancer Prevention and Control Network (CCPCN): Performance Monitoring for Cervical Cancer Screening Programs in Canada.  Ottawa, Public Health Agency of Canada; 2009 Jan.
  2. Canadian Partnership Against Cancer.  Cervical cancer screening in Canada: Monitoring program performance 2009–2011.  Toronto: Canadian Partnership Against Cancer; 2013.
  3. Fung-Kee-Fung M, Howlett R, Oliver T, Murphy J, Elit L, Strychowsky J, et al. The optimum organization for the delivery of colposcopy service in Ontario. Toronto (ON): Cancer Care Ontario; 2008 Feb 14. Program in Evidence-based Care Evidence-based Series on Colposcopy.
  4. Society of Obstetricians and Gyneacologists of Canada.  Colposcopic management of abnormal cervical cytology and histology.   J Obstet Gynaecol Can. 2012;34(12):1188–1202.
Calculations for the indicator ((Total number of Ontario screen-eligible women, 21-69 years old, with a high-grade cervical abnormality on a Pap test, who underwent colposcopy or definitive treatment within 6 months of the high-grade abnormal screen date / Total number of Ontario screen-eligible women, 21-69 years old, with a high-grade cervical abnormality on a Pap test in a given year) x 100 = Follow-up
Standardized Rate Calculation N/A
Unit Percentage (%)
Data sources
  • ​CytoBase - Pap tests
  • OHIP CHDB (Claims History Database) – Previous Pap tests, colposcopies, definitive procedure claims, hysterectomy claims
  • OCR (Ontario Cancer Registry) -  Resolved invasive cervical cancers
  • RPDB (Registered Persons Database) - Demographics
  • PCCF+, version 6D - Residence and socio-demographic information
Time Frame

2013-2016

Geographic Scale
  • Provincial (Ontario)
  • LHIN of residence
Denominator description

​Total number of Ontario Screen-eligible women, 21-69 years old at the index date, who had a high-grade cervical abnormality on a Pap test 

  • Index date was defined as the date of the most recent high-grade cervical abnormality per person by date of specimen collection in CytoBase in each calendar year
  • High-grade cervical dysplasia was defined as:

Pap test category: Version 2
ASC-H: 4.4.5
AGC: 4.5.1, 4.5.2, 4.5.3, 4.5.4, 4.5.5, 4.5.7, 4.5.9
Adeno in-situ: 4.5.8, 4.6
HSIL: 4.8

  • Each woman was counted once per given year regardless of the number of tests performed
  • The RPDB address closest to the index date was used to assign postal code
  • LHIN assignment was determined using PCCF+, version 6D; residential postal code was used to identify LHIN

Exclusions:

  • Women with a missing or invalid HIN, date of birth, LHIN or postal code
  • Women who died during the follow-up period
  • Women diagnosed with an invasive cervical cancer before the index date; prior diagnosis of cervical cancer was defined as: ICD-O-3 codes C53, a morphology indicative of cervical cancer, microscopically confirmed with a path report
  • Women with a hysterectomy before the index Pap date
  • Women with a hysterectomy were identified through OHIP, using the following fee codes:
  • E862A – When hysterectomy is performed laparoscopically, or with laparoscopic assistance
  • P042A – Obstetrics – labour – delivery – caesarean section including hysterectomy
  • Q140A – Exclusion code for enrolled female patients aged 35-70 with hysterectomy
  • S710A – Hysterectomy - with or without adnexa (unless otherwise specified)  – with omentectomy for malignancy
  • S727A – Ovarian debulking for stage 2C, 3B or 4 ovarian cancer and may include hysterectomy
  • S757A – Hysterectomy – with or without adnexa (unless otherwise specified) – abdominal – total or subtotal
  • S758A – Hysterectomy - with or without adnexa (unless otherwise specified) – with anterior and posterior vaginal repair and including enterocoele and/or vault prolapse repair when rendered
  • S759A - Hysterectomy - with or without adnexa (unless otherwise specified) – with anterior or posterior vaginal repair and including enterocoele and/or vault prolapse repair when rendered
  • S762A - Hysterectomy - with or without adnexa (unless otherwise specified) – radical trachelectomy - excluding node dissection
  • S763A - Hysterectomy - with or without adnexa (unless otherwise specified) – radical (Wertheim or Schauta) - includes node dissection
  • S765A – Amputation of cervix
  • S766A- Cervix uteri - Exc - cervical stump – abdominal
  • S767A- Cervix uteri - exc - Cervical stump – vaginal
  • S816A - Hysterectomy - with or without adnexa (unless otherwise specified) – vaginal
Numerator description

​Total number of women with a high-grade cervical abnormality on Pap test who underwent colposcopy or definitive treatment within six months of the high-grade abnormal Pap test

Colposcopy was defined using the following fee codes in OHIP:

  • Z731 - Initial investigation of abnormal cytology of vulva and/or vagina or cervix under colposcopic technique with or without biopsy(ies) and/or endocervical curetting
  • Z787 - Follow-up colposcopy with biopsy(ies) with or without endocervical curetting
  • Z730 – Follow-up colposcopy without biopsy with or without endocervical curetting
  • If no record was found for a subsequent colposcopy after the high-grade cervical abnormality Pap test, other definitive procedures were included; these procedures were identified through OHIP claims as:
  • Z732 Cryotherapy
  • Z724 Electro
  • Z766 Electrosurgical Excision Procedure (LEEP)
  • S744 Cervix - cone biopsy - any technique, with or without D&C
  • Z720 Cervix Biopsy - with or without fulguration
  • Z729 Cryoconization, electroconization or CO2 laser therapy with or without curettage for premalignant lesion (dysplasia or carcinoma in-situ), out-patient procedure
  • If no record was found for a colposcopy or one of the procedures listed above, the woman was still assumed to be followed up provided if a hysterectomy was performed within six months following the high-grade abnormal Pap test
  • If a woman had multiple colposcopies or multiple procedures, the earliest colposcopy or procedure was selected
  • If a woman had colposcopy within +/- 7 days of her Pap test, preceding tests in CytoBase and OHIP up to six months before were used to verify if this colposcopy might have been associated with a previous Pap test. If there was a previous Pap test in the specified time period, that Pap test would be used as the index Pap.

The following codes were used to identify Pap tests through OHIP:

 

  • E430A: add-on to A003, A004, A005, A006, A205, A203, A206 when pap performed outside hospital
  • G365A: Periodic-pap smear – once per 33 months
  • E431A:  When Papanicolaou smear is performed outside of hospital, to G394.
  • G394A: Additional for follow-up of abnormal or inadequate smears
  • L713A: Lab.med.-anat path,hist,cyt-cytol-gynaecological specimen
  • L733A: Cervicovaginal specimen (monolayer cell methodology)
  • L812A: Cervical vaginal specimens including all types of cellular abnormality, assessment of flora, and/or cytohormonal evaluation
  • Q678A: Gynaecology – pap smear – periodic – nurse practitioners
  • L643A: Lab Med - Microbiol - Microscopy - Smear Only, Gram/Pap Stain

 

Considerations  N/A
Data availability & limitations
  • Pap test results are available in CytoBase only
  • CytoBase includes only Pap tests analyzed in community-based laboratories in Ontario; Pap tests analyzed in Ontario hospitals and Community Health Centres are not captured in CytoBase
  • It is difficult to determine whether a Pap test in CytoBase and/or OHIP was done for screening or diagnostic purposes, and therefore, some Pap tests included in these analyses may have been performed for diagnostic purposes
CSQI Year 2018