National Cervical Screening Program monitoring report 2025

Cancer is a group of several hundred diseases in which abnormal cells are not destroyed naturally by the body, but instead multiply and spread out of control. Cancers are distinguished from each other by the specific type of cell involved and by the place in the body in which the disease began.

Cervical cancer affects the cells of the uterine cervix, which is the lower part (or 'neck') of the uterus where it joins the upper end of the vagina (Figure cervical cancer 1). Cervical cancer develops when abnormal cells in the lining of the cervix begin to multiply out of control and form precancerous abnormalities. If undetected, these abnormalities can develop into cervical cancer and spread into the surrounding tissue.

Figure cervical cancer 1: Anatomy of the female reproductive system

© 2021 Terese Winslow LLC, U.S. Govt. has certain rights

Reproduced with permission of the copyright owner.

Worldwide, cervical cancer is the fourth most common cancer affecting women, ranking fourth for both incidence and mortality; however, its burden is not equal globally. Cervical cancer ranks second in incidence and mortality behind breast cancer in lower Human Development Index countries without cervical screening programs. Cervical cancer incidence is above 25 new cases per 100,000 women in some such countries, compared with a relatively low incidence of 6 new cases per 100,000 women of all ages in Australia (world age-standardised rates) (Bray et al. 2018). This is due to Australia having an organised population-based screening program in place since 1991 that has prevented many cervical cancers by detecting and treating high-grade cervical abnormalities before any possible progression to cervical cancer.

Research performed by the Australian Institute of Health and Welfare (AIHW) using linked cervical screening, cancer, and death data showed that 72% of cervical cancers diagnosed between 2002 and 2012 in women aged 20–69 occurred in those who had either never screened or were lapsed screeners, demonstrating the effectiveness of Australia's cervical screening program in preventing cervical cancer. This research further showed that cervical cancers that did occur in recently screened women were less likely to cause death than those diagnosed in women who had never screened, which is likely due to these cancers being detected at an earlier stage (AIHW 2019).

Human papillomavirus (HPV) plays a major role in the development of precancerous cervical abnormalities and cervical cancer, with HPV being the underlying cause of almost 100% of squamous cell carcinomas and up to 90% of adenocarcinomas (Brotherton et al. 2020) (see Box cervical cancer 1 for further information).

The 4 major steps in most cervical cancer development are:

1. infection with HPV (acquired through sexual contact),
2. viral persistence (as most HPV infections clear with no treatment),
3. progression to precancerous abnormalities (many of which will also regress with no treatment), and
4. invasive cervical cancer (Schiffman et al. 2007; Schiffman and Kjaer 2003) (Figure cervical cancer 2).

As indicated by the arrows in Figure cervical cancer 2, the preliminary steps towards the eventual development of cervical cancer are not unidirectional. Most HPV-infected cells return to normal, and a large proportion of precancerous abnormalities do not progress to cervical cancer, even without treatment. However, it is not possible to know which precancerous abnormalities will regress without treatment, and so the detection and treatment of all precancerous abnormalities is important.

While the cell changes caused by persistent infection with oncogenic HPV can cause precancerous changes to the cervix, a range of other factors will influence whether precancerous changes will progress to cervical cancer; these include smoking, multiparity (specifically, more than 5 full-term pregnancies), a young age at first full term pregnancy, oral contraceptive use, and immunosuppression (Cancer Council Australia 2014).

Figure cervical cancer 2: Role of HPV infection in the development of cervical cancer

Source: Reproduced with permission from M Schiffman, National Cancer Institute (Schiffman and Kjaer 2003).

Australia is set to become the first country in the world to actively eliminate cervical cancer, with modelling predicting that the incidence of cervical cancer will drop to fewer than 4 new cases per 100,000 women by 2035, and to fewer than 1 new case per 100,000 women by 2066 (Hall et al. 2019).

A greater understanding of the role of HPV in most cervical cancers (Box cervical cancer 1) has led to two major developments in Australia, which are behind these anticipated further reductions in the incidence of cervical cancer in Australia. The first of these developments is the introduction of a national HPV vaccination program in April 2007 (Box cervical cancer 2). The second is a renewed national cervical screening program which commenced on 1 December 2017 and uses an HPV test as its primary screening test (Hall et al. 2019).

Note that, while Australia introduced primary prevention of cervical cancer in the form of HPV vaccination that complements the existing cervical screening program, cervical screening remains a vital secondary prevention strategy for those who are HPV-vaccinated and those who are unvaccinated. It is important that all eligible women and people with a cervix participate in cervical screening, irrespective of their HPV vaccination status.