1. Cervical cancer in Australia

Australian rates of cervical cancer incidence and death are among the lowest in the world.[1] This is largely attributed to the successful introduction in 1991 of the National Cervical Screening Program (NCSP). The NSCP is an organised approach to cervical screening that operates as a joint program of the Australian Government and the state and territory governments. It is implemented by a range of health professionals, including general practitioners, women’s health nurses, gynaecologists, gynaecological oncologists, cytologists and pathologists.

In 1982 cervical cancer was the sixth most common cancer in Australian women and by 1991 it had fallen to eighth ranking, presumably related to opportunistic screening for cervical cancer. Following the introduction of the NCSP in 1991 there was a steady fall in the incidence of cervical cancer, and by 2009 it ranked the twelfth most common cancer in Australian women.[2] Table 1.1 shows the Australian incidence and mortality rates for cervical cancer (age standardised to the World Standard Population) in comparison with other countries for the period up to and including 2012.

Table 1.1. Incidence and mortality rates for cervical cancer (selected countries), 2012

ASRW: age-standardised rate (World Standard Population) except for Australia (see note)

ASR: age-standardised rate (Australian population)

Notes:

Incidence is the number of new cases of cervical cancer per 100,000 women, age-standardised to the World Standard Population.

Mortality is the number of deaths from cervical cancer per 100,000 women, age-standardised to the World Standard Population.

While incidence and mortality rates have been age-standardised to the World Standard Population, which is appropriate for international comparisons, the remainder of incidence and mortality rates have been age-standardised to the Australian population at 30 June 2001, which is appropriate for comparisons within Australia (such as over time or across population groups).

Source: GLOBOCAN (2012)[1]

Since 1991 Australian incidence and mortality rates for cervical cancer have decreased by approximately 50%, and are among the lowest in the world.[2]

Figure 1.1 shows the time trends in incidence of cervical cancer in Australian women aged 20–69 years.

The ASR for cervical cancer incidence fell slowly from 14.2 new cases per 100,000 women in 1982, to 13.3 in 1991,[2] probably related to uptake of opportunistic screening. The organised approach provided by the NCSP commenced in 1991, following which the rate fell rapidly to reach a plateau of about 7 new cases per 100,000 women between 2002 and 2011.[2] Overall, the incidence rate fell by 51% between 1982 and 2011. A plateau in incidence rates was evident from about 2004.

The ASR for cervical cancer incidence followed a similar trend when considering only women in the target age group 20–69 years, falling only slightly from 19.0 new cases per 100,000 women in 1982, to 17.2 in 1991, before falling rapidly to reach a plateau of about 9 new cases per 100,000 women between 2002 and 2011 (Figure 1.1).

Figure 1.1. Incidence of cervical cancer in women aged 20–69 years, 1982–2011

Note: Incidence rate is the number of new cases of cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001.

Source: Australian Institute of Health and Welfare (AIHW) analysis of the Australian Cancer Database 2011 [2]

In 1982 there were 963 new cases of cervical cancer in Australia, 826 of which occurred in the target age group 20–69 years. By 1994, a few years after the introduction of the NCSP, the number of new cases peaked at 1144 new cases (937 in women 20–69 years). By 2002 this had decreased to 690 new cases and of these 558 occurred in the target age group 20–69 years. In 2011 there were 801 new cases overall, with an ASR of 6.9 per 100,000 women, and 682 occurred in women in the target age group of 20–69 years.[2]

Figure 1.2 shows the time trends in mortality from cervical cancer in Australian women aged 20–69 years.

Figure 1.2. Mortality from cervical cancer in women aged 20–69 years, 1982–2012

Note: Mortality rate is the number of deaths from cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001.

Source: AIHW analysis of the National Mortality Database[2]

In 2012 there were 226 deaths from cervical cancer (with an ASR of 1.8 per 100,000 women), and 143 occurred in the target age group of 20–69 years.[2] A plateau in mortality rates was reached in about 2004.

Incidence rates for cervical cancer by histological type over time

Figure 1.3 shows the time trends between 1989 and 2010 in the incidence of the various histological types of cervical cancer.[2]

Figure 1.3. Incidence of carcinoma of the cervix (squamous cell carcinoma, adenocarcinoma, adenosquamous carcinoma and other carcinomas) in women aged 20–69 years, 1982–2011

Note: Incidence rate is the number of new cases of cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001.

Source: AIHW analysis of the Australian Cancer Database 2011[2]

The incidence of squamous cancers fell between 1991 and 2002, with little fall thereafter. In contrast, the incidence of adenocarcinoma has been relatively stable. In 1982 the ASR of adenocarcinoma was 2.1 new cases per 100,000 women; by 1991 it had risen to 2.8, from which it fell to a minimum of 2.0 in 2002 and thereafter rose again to nearly reach the levels of the early 1990s.[2] Incidence rates of adenosquamous carcinoma and of other and unspecified carcinoma appear to have fallen by about 50% since the early 1990s.

The glandular cancers now comprise a quarter of all cervical cancers, whereas in 1991 they accounted for 5–10% of cervical cancers.[2] The failure to reduce the incidence of adenocarcinoma is usually attributed to difficulties in sampling, less effective identification and more difficult interpretation of abnormal glandular cells.[3][4]

The incidence of glandular cancers has not changed significantly since the inception of the NCSP. Glandular cancers are less frequent than squamous cancers, which the original NCSP was designed to detect. Improvement of the rate of detection of glandular precursor lesions was one aspect considered in the strategy for renewal of the NCSP, to ensure that Australian women are offered optimal cervical screening.

Incidence and mortality for different age groups between 1982 and 2011

Incident cancers decreased over time in each age group from 25–29 years to 85+ years (Figure 1.4). Before the introduction of the NCSP there was a clear second (and higher) peak in the graph of incidence with age in women from 60 years onwards. This peak appears to have reduced substantially over time, possibly because of increased uptake of screening by older women in the organised program. There is also some suggestion that this peak has moved to women in their late seventies and eighties.

Figure 1.4. Incidence of cervical cancer in women by 5-year age group, 1982–1991, 1992–2001, and 2002–2011

Note: Incidence rate is the number of new cases of cervical cancer per 100,000 women.

Source: Australian Cancer Incidence and Mortality[5]

Similarly, reductions in mortality has been recorded over the same period. Figure 1.5 shows the reduction in the number of deaths during the period 1982–2011 and the variation among women of different age groups. The major reduction in mortality occurred after the introduction of the organised approach to cervical screening in 1991, with the greatest absolute reduction in women in their late sixties and early seventies. This effect is most notable in the period 2002–2012, which does not show the small rise in mortality for women around the age of 65–69 years that is apparent in both the 1982–1991 and 1992–2001 periods.

Figure 1.5. Mortality from cervical cancer in women by 5-year age group, 1982–1991, 1992–2001, and 2002–2012

Note: Mortality rate is the number of deaths from cervical cancer per 100,000 women. Source: Australian Cancer Incidence and Mortality[5]

Since 1991 cervical screening, using a Pap smear every 2 years, has been recommended for all Australian women aged 20–69 years.

General population

Around 6 in 10 women participate in the NCSP every 2 years. In 2012–2013 (and in preliminary data available for 2013–2014), more than 3.8 million women participated in the NCSP. This was 58% of women aged 20–69 years, and is similar to the 2010–2011 and 2011–2012 periods, for which participation rates were 57% and 58%, respectively. Women under 25 years have the lowest participation rates. Figure 1.6 shows the participation in the NCSP by age over intervals of 2, 3 and 5 years. Five-year participation is more than 80%.

Figure 1.6. Participation of women aged 20–69 years, by age, over 2 years (2012–2013), 3 years (2011–2013), and 5 years (2009–2013)

Participation rate is the number of women screened as a percentage of the resident population (Australian Bureau of Statistics estimates) adjusted to include only women with an intact cervix (using hysterectomy fractions derived from the National Hospital Morbidity Database).

Source: AIHW analysis of state and territory cervical screening register data[2]

Remoteness and socioeconomic status

Participation differed little across remoteness areas. ASRs range between 58% and 60% in all areas except for very remote areas (55%). However, there is a clear trend of increasing participation with increasing socioeconomic status of residence, from 52% in areas of lowest socioeconomic status to 64% in areas of highest socioeconomic status.

Figure 1.7. Participation of women aged 20–69, by remoteness area and by socioeconomic status, 2012–2013

Notes: Participation rate is the number of women screened as a percentage of the resident population (Australian Bureau of Statistics estimates), adjusted to include only women with an intact cervix (using hysterectomy fractions derived from the National Hospital Morbidity Database), age-standardised to the Australian population at 30 June 2001.

Source: AIHW analysis of state and territory cervical screening register data[2]

Women who do not participate as recommended in the NCSP

Women who do not participate as recommended in the NCSP Failure to participate in the NCSP is related to increased incidence of cervical cancer.

Fifty per cent of cervical cancers occur in women who have never been screened and a further 28% occur in women who do not screen regularly or are lapsed screening participants. This finding suggests that cancer incidence patterns do follow rates of participation in the NCSP.[6]

Socioeconomic status

Figure 1.8 shows the incidence of cervical cancer in women according to socioeconomic status in 2006– 2009. This would appear to reflect the different participation rates related to socioeconomic status as shown in Figure 1.7. In particular, the incidence of cervical cancer was lowest for women living in areas of highest socioeconomic status (ASR 7.4 new cases per 100,000 women) and it was this group that has the highest participation rate. The four lowest socioeconomic groups had similar rates, with an ASR of 9–10 new cases per 100,000 women.

Figure 1.8. Incidence of cervical cancer in women aged 20–69, by socioeconomic status, 2006–2009

Note: Incidence rate is the number of new cases of cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001.

Source: AIHW analysis of the Australian Cancer Database 2011[2]

Figure 1.9 shows mortality from cervical cancer in women according to socioeconomic status in 2007– 2011. This would again appear to reflect the different participation rates related to socioeconomic status as shown in Figure 1.7, and incidence shown in Figure 1.8. Mortality from cervical cancer was lowest for women living in areas of highest socioeconomic status (ASR 1.2 deaths per 100,000 women), broadly increased with decreasing socioeconomic status, and was highest in the lowest socioeconomic group (ASR 2.8 deaths per 100,000 women). The variation of mortality with socioeconomic status was somewhat greater than for incidence, however, suggesting that treatment factors and variations in survival also play a role in the difference.

Figure 1.9. Mortality from cervical cancer in women aged 20–69 years, by socioeconomic status, 2007–2011

Note: Mortality rate is the number of deaths from cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001.

Source: AIHW National Mortality Database.

Source: AIHW analysis of the National Mortality Database [7]

Geographical variation

The incidence and mortality of cervical cancer shows some geographical variation within Australia. This is most noticeable when comparing data from major cities, and inner and outer regional areas, with remote and very remote areas, as shown in Figure 1.10.

During the period 2005–2009 major cities and inner and outer regional areas had incidence rates of 9.0 and 9.3 new cases per 100,000 women, respectively. The incidence in remote and very remote areas was significantly higher, at 12.7 new cases per 100,000 women.[2]

Figure 1.10. Incidence of cervical cancer in women aged 20–69, by remoteness area, 2005–2009

Note: Incidence rate is the number of new cases of cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001. Source: AIHW analysis of the AIHW Australian Cancer Database 2011[2]

Figure 1.11 shows that mortality was similar in major cities (1.8 deaths per 100,000 women) and inner and outer regional areas (2.2 deaths per 100,000 women), but mortality in remote and very remote areas was significantly higher (3.4 deaths per 100,000 women). A higher proportion of Aboriginal and Torres Strait Islander women live in remote and very remote areas, and Aboriginal and Torres Strait Islander women experience higher incidence and mortality from cervical cancer.[2]

Figure 1.11. Mortality from cervical cancer in women aged 20–69 years, by remoteness area, 2008–2012

Note: Mortality rate is the number of deaths from cervical cancer per 100,000 women, age-standardised to the Australian population at 30 June 2001. Source: AIHW analysis of the AIHW National Mortality Database[2]

Aboriginal and Torres Strait Islander women

Indigenous status has not been recorded in cancer and mortality registers by all jurisdictions for all time periods. Data from those jurisdictions with adequate reporting of cervical cancer by Indigenous status show a significantly higher incidence among Aboriginal and Torres Strait Islander women during 2005– 2009, with an ASR of 19.5 new cases per 100,000 women, compared with 8.7 among non-Aboriginal and Torres Strait Islander women (Figure 1.12). Similarly, available data show a significantly higher mortality rate among Aboriginal and Torres Strait Islander women during 2008–2012, at 7.7 deaths per 100,000 women, compared with 1.9 deaths per 100,000 women among non-Aboriginal and Torres Strait Islander women (Figure 1.13).

Figure 1.12. Incidence of cervical cancer in women aged 20–69 years (NSW, QLD, WA, NT) by Indigenous status, 2005–2009

Notes: Incidence rate is the number of new cases of cervical cancer per 100,000 women, age standardised to the Australian population at 30 June 2001.

Only data from New South Wales, Queensland, Western Australia and the Northern Territory only were considered to have adequate levels of Indigenous identification in cancer registration data.

Source: AIHW analysis of the Australian Cancer Database 2011[2]

Figure 1.13. Mortality from cervical cancer in women aged 20–69 years(NSW, QLD, WA, SA and NT), by Indigenous status, 2008–2012

Notes: Mortality rate is the number of deaths from cervical cancer per 100,000 women, age standardised to the Australian population at 30 June 2001.

Only data from New South Wales, Queensland, Western Australia, South Australia and the Northern Territory were considered to have adequate levels of Indigenous identification in cancer mortality data.

Source: AIHW analysis of the National Mortality Database[2]

NCSP participation rates for Aboriginal and Torres Strait Islander women are not available because information on Indigenous status is not collected on pathology forms in all jurisdictions. However, there is evidence that Aboriginal and Torres Strait Islander women are under-screened, and that this contributes to their higher cervical cancer incidence and mortality.[8][9][10]

Survival

Improvements in speed of referral, investigation, diagnosis, staging of disease, treatment efficacy and availability, subspecialist care, multidisciplinary team management and patient quality of life, have translated into a modest increase in 5-year relative survival for women diagnosed with cervical cancer. Between time periods 1982–1987 and 2006–2010, the 5-year relative survival (the ratio of observed survival to expected survival) for cervical cancer rose substantially, from 68% in 1982–1987 to 71% in 1988–1993, and to 71.9% in 2007–2011.[11][12]

Incidence

In the absence of any change to the screening program, and assuming that the ASR of 6.7 new cases per 100,000 women will remain constant, the actual number of cases of cervical cancer will rise slowly over the next few years due to population growth and ageing (Figure 1.14). However these projections are not forecasts; they do not allow for future changes in methods of cancer detection or prevention, nor the likely impact of vaccination against human papillomavirus (HPV) in reducing the incidence of cervical cancer in young women.

Figure 1.14. Incidence of cervical cancer observed for 1982–2007 and projected to 2020

Note: Incidence rate is the number of new cases of cervical cancer per 100,000 women, age standardised to the Australian population at 30 June 2001.

Source: AIHW analysis of the AIHW Australian Cancer Database 2007[13]

The future of cervical cancer control is in prevention of the disease. Australia has a two-pronged approach: the primary prevention strategy is school-based HPV vaccination, and the secondary prevention strategy is HPV screening (replacing the Pap smear) commencing in December 2017.

National HPV Vaccination Program

The National HPV Vaccination Program commenced for girls in 2007 and for boys in 2013, using a quadrivalent vaccine against HPV types 6, 11, 16 and 18 (Gardasil). This vaccine is effective in preventing infection with the oncogenic HPV types (16 and 18) that cause 70–80% of cervical cancer in Australia.

The National HPV Vaccination Program Register has reported an initial vaccination uptake of 73% for the full course of three doses among eligible girls aged 12–13 years nationally. Reductions in the prevalence of infections with vaccine-included oncogenic HPV types, anogenital warts and histologically confirmed HSIL have already been documented in young women, including a reduction in vaccine-included type infections in unvaccinated young women.[7][14][15][16][17]

A next-generation 9-valent vaccine, with the capacity to prevent up to 90% of cervical cancers in effectively vaccinated females, is expected to be considered for inclusion in the National HPV Vaccination Program. However, this is not expected to have an immediate effect on cervical screening because the new vaccine would be delivered to girls aged 12–13 years, who would not be eligible for screening for a number of years.

Renewal of the National Cervical Screening Program

Renewal of the NCSP commenced in late 2011, to ensure the continuing success of the program and to ensure that that all Australian women – HPV vaccinated and unvaccinated – have access to a cervical screening program that is based on current evidence and best practice.

Factors stimulating the renewal include:

• a plateau in the incidence of cervical squamous cell carcinoma since 2002
• lack of significant reduction in glandular carcinomas since the introduction of the NCSP
• new knowledge about the natural history of cervical cancer (see Chapter 2. The rationale for primary HPV testing)
• new evidence about the optimal screening age range and interval
• new tests, such as liquid based cytology (LBC) and HPV testing
• the National Human Papillomavirus Vaccination Program, which commenced in 2007 for girls and in 2013 for boys.

After a rigorous and transparent process involving an external evidence review[18] and economic modelling[19], the Australian Medical Services Advisory Committee (MSAC) released its recommendations in April 2014.

In December 2017 Australia is changing to a renewed NCSP based on 5-yearly cervical screening using a primary HPV test with partial genotyping and reflex LBC triage, for women aged 25–69 years, with exit testing up to age 74 years. Invitations and reminders will be sent to women, and a provision has been made for self-collection of a HPV sample for an under-screened or never-screened woman. The modelled evaluation performed for the MSAC evaluation of the renewed program estimated that the new program will deliver a further 15–22% reduction in incidence and mortality from cervical cancer in Australian women.[19]

Subsequent modelling, taking into account post-colposcopy management as recommended in these guidelines, has predicted reductions of 31-36% in cervical cancer incidence and mortality in unvaccinated cohorts, and reductions of 24–29% in cohorts offered vaccination (see Appendix A. Modelled evaluation of the predicted benefits, harms and cost-effectiveness of the renewed National Cervical Screening Program (NCSP) in conjunction with these guideline recommendations).

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