Notes on the data: Screening programs - Cervical screening

Cervical screening outcomes - High grade abnormality, females aged 20 to 69 years, 2015 and 2016 (NSW, Vic, SA, and WA)

 

Policy context:  Cervical cancer is a largely preventable disease in Australia, mainly due to primary prevention measures through the National HPV Vaccination Program, which vaccinates women against the oncogenic HPV (human papillomavirus) types that cause the majority of cervical cancer. Secondary prevention of cervical cancer is through the National Cervical Screening Program (NCSP) which aims to detect and treat precancerous abnormalities before any possible progression to cervical cancer [1]. It is estimated that up to 90% of the commonest type of cervical cancer may be prevented, if cell changes are detected and treated early [2].

Cervical cancer is a rare outcome of persistent infection with human papillomavirus (HPV), and infection with a high-risk HPV type is necessary, although not sufficient, for the development of cervical cancer [3]. On screening, high-grade abnormalities can occur after persistent infection with HPV [1]. The probability of a high-grade abnormality progressing to cancer increases with age and extent of abnormality [4], but is still a very rare outcome, with regression rates for high-grade abnormalities estimated to be at least 80% [5].

Incidence and mortality of cervical cancer in Australia remain low, consistent with the NCSP's aim to reduce incidence and mortality. In 2015, there were 9 new cases of cervical cancer diagnosed, and 2 deaths, per 100,000 women (aged 20-69). These rates have remained steady from previous years although it must be noted that both incidence and mortality have halved between the introduction of the NCSP in 1991 to 2002 [1,6]. However, incidence for Aboriginal and Torres Strait Islander women has been estimated to be more than double, and mortality to be four times, that of other Australian women [1].

References

  1. Australian Institute of Health and Welfare (AIHW). Cervical screening in Australia 2018. Cat. no. CAN 111. Canberra: AIHW; 2018. Available from: https://www.aihw.gov.au/getmedia/8a26b34d-a912-4f01-b646-dc5d0ca54f03/aihw-can-111.pdf.aspx?inline=true; last accessed 17 December 2019
  2. Australian Institute of Health and Welfare (AIHW). Cervical screening in Australia 2010-2011. Cat. no. CAN 72. Canberra: AIHW; 2013.
  3. Bosch FX, Lorincz A, Muñoz N, Meijer CJ, Shah KV. The causal relation between human papillomavirus and cervical cancer. J Clin Pathol. 2002;55(4):244-65.
  4. National Health and Medical Research Council (NHMRC). Screening to prevent cervical cancer: guidelines for the management of asymptomatic women with screen detected abnormalities. (Reference no. WH39). Canberra: NHMRC; 2005 [cited 2013 Oct 18]. Available from: http://www.nhmrc.gov.au/guidelines/publications/wh39
  5. Raffle AE, Alden B, Quinn M, Babb PJ, Brett MT. Outcomes of screening to prevent cancer: analysis of cumulative incidence of cervical abnormality and modelling of cases and deaths prevented. BMJ. 2003;326(7395):901.
  6. Australian Institute of Health and Welfare (AIHW). Cervical screening in Australia 2019. Cat. no. CAn 124. Canberra: AIHW; 2019. Available from: https://www.aihw.gov.au/getmedia/6a9ffb2c-0c3b-45a1-b7b5-0c259bde634c/aihw-can-124.pdf.aspx?inline=true; last accessed 17 December 2019
 

Notes:  Incorrect data for Victoria were identified in the previous release. The corrected data were published in February 2020.

Cervical screening outcomes for the 24 month period to the end of each calendar year are based on the number of women with an abnormal pap smear as an age-standardised rate of the number of women screened in the corresponding calendar years. If a woman has attended more than once in the 24 months with two high-grade abnormality results, she is counted once only, and her age is taken from the first visit. However, note that cervical screening outcomes for Victoria are calculated differently - see details here.

High grade abnormalities are cytology test results S4, S5, S6, E3, E4 and E5 according to the national cytology coding schedule.

Rates of high grade abnormality within geographic areas along the Victorian and New South Wales borders, specifically the Murray PHN and the Albury Local Government Authority, may be under estimated because women tested in Victoria but who reside in New South Wales may not be fully allocated to the New South Wales geographic area.

Data are not currently available for Queensland, Tasmania, the Australian Capital Territory and the Northern Territory; data for these jurisdictions may become available when the National Cancer Screening Register is fully operational.

 

Geography:  Data available by Population Health Area, Local Government Area, Primary Health Network, quintile of socioeconomic disadvantage of area and Remoteness Areas

 

Numerator:  Number of individual women aged 20 to 69 years with a high grade abnormality detected (cytology) over a 24 month period ending 31 December 2016

 

Denominator:  Number of women aged 20 to 69 years screened over a 24 month period ending 31 December 2016

 

Detail of analysis:  Indirectly age-standardised rate per 1,000 women screened; the standard population is the population of each respective jurisdiction

 

Source:  Compiled by PHIDU based on data from the NSW Department of Health and NSW Central Cancer Registry, 2015 and 2016; Victorian Cervical Cytology Register, 2015 and 2016; SA Cervix Screening Program, 2015 and 2016 and Western Australia Cervical Cytology Register, 2015 and 2016

 

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