Almost 1 million women across NSW are overdue for their Pap test, with western Sydney women least likely to have undergone the cervical cancer screening in the past two years.
The figures were released on the eve of the big switch to a new national cervical screening program, as state health experts mobilise to dispel misinformation surrounding the end of the Pap smear that could discourage women from backing the new test.
From December 1, the new program will act as an early warning system for cervical cancer, and is predicted to cut incidence and mortality rates by at least 20 per cent.
The new test is designed to detect human papillomavirus (HPV), which causes the abnormal cell changes responsible for 99 per cent of cervical cancers, while the Pap test can only detect the abnormal cells once they have manifested.
An estimated 912 women will be diagnosed with cervical cancer in 2017. More than one in four cervical cancer patients will die within five years of their diagnosis, according to national statistics.
The women most in need of timely screening are those already overdue for their Pap tests, Cancer Institute NSW experts warn.
A total of 959,690 women aged between 20 and 69 years (excluding those who have had a hysterectomy) did not have a Pap test between July 1, 2015 and June 30 this year, according to data from the NSW Pap test register and the NSW Ministry of Health.
Western Sydney had the largest number and proportion of underscreened women across all NSW local health districts, with 51.5 per cent (137,250 women) not having had a Pap test over the two-year period.
Campbelltown had the lowest participation rate of all local government areas (LGAs) in greater Sydney, with 55.8 per cent of women overdue for the test.
Another eight Sydney LGAs had participation rates below 50 per cent, including Blacktown (46.1 per cent), Holroyd (47.1 per cent), Penrith (48.1 per cent), and Auburn (48.1 per cent).
Sydney's north and coastal suburbs had the highest screening rates, though more than one in four women were still overdue for their Pap test in the suburbs with the best participation results: Mosman (72 per cent), Woollahra (71.7) per cent, and Waverley (69.8 per cent).
Sydney areas with the lowest cervical cancer screening rates
1. Campbelltown 44.2 per cent
2. Blacktown 46.1 per cent
3. Holroyd 47.1 per cent
4. Penrith 48.1 per cent
5. Auburn 48.1 per cent
6. Liverpool 48.3 per cent
7. Camden 48.7 per cent
8. Burwood 48.9 per cent
9. Strathfield 49.4 per cent
10. Parramatta 50.4 per cent
Sydney areas with the highest cervical cancer screening rates
1. Mosman 72 per cent
2. Woollahra 71.7 per cent
3. Waverley 69.8 per cent
4. Lane Cove 69.3 per cent
5. Hunters Hill 68.6 per cent
6. Pittwater 68.5 per cent
7. Manly 67.9 per cent
8. Leichhardt 66 per cent
9. Warringah 65.4 per cent
10. Ku-ring-gai 64.8 per cent
The same uncomfortable procedure, just less often
Women won't notice any different at their screening appointment. A doctor or nurse will take a small sample of cells from a woman's cervix and send it to a pathology laboratory for testing.
But the time between tests is now five years, instead of two years.
Women who test negative for HPV run a very low risk of developing cervical cancer for a long time - often over 10 years - justifying the longer interval.
The program was a "win-win scenario" said director of research at Cancer Council NSW, Professor Karen Canfell.
Women will have access to a more accurate test, with fewer appointments with the speculum.
"It's not women's favourite procedure, so the good news is they'll need to go far fewer times and [they] still receive 20 per cent better protection," she said.
All women aged between 25 and 74 years who have ever been sexually active will need to be tested, instead of women 18 to 69 years.
Why some women avoid screening
The variation across Sydney was indicative of the socioeconomic and cultural divides that influence whether women are likely to seek out cervical screening.
Director of cancer screening and prevention Sarah McGill said stigma or a sense of shame in some culturally and linguistically diverse populations could make it difficult for women to seek out cervical cancer and screening, especially from male doctors in their close-knit communities.
"This may be linked to the intimate nature of the screening test, or the fact that HPV is a sexually transmitted infection [which] may imply promiscuity in certain communities.
"Women and their communities should know that people can contract the HPV virus despite having only one sexual partner or being in a monogamous relationship," Ms McGill said, adding health authorities were working with these groups to break down the barriers to screening.
Medical director of Family Planning NSW Dr Deborah Bateson said the organisation offered interpreters and youth-friendly clinics where women could feel comfortable having a conversation about the new screening program.
"Family Planning NSW is here for people with disability, Aboriginal and Torres Strait Islander women, and anyone who wants to talk about the changes to the screening program and what it means for them," Dr Bateson said.
Vaccination not enough
The success of the HPV immunisation program meant the screening program would offer younger vaccinated women "double-barrel protection", Professor Canfell said. But vaccinated women should not be complacent.
"All women still need to be screened, whether they are vaccinated or not," she said.
HPV screening will allow doctors to stratify a woman's cervical cancer risk and set her on the right management pathway, whether it be HPV screening in five years' time for women who return a negative result, cytology testing, physical investigation or immediate treatment depending on the initial test results, Professor Canfell said.
The new program would perform a delicate balancing act between detecting early warning signs and the potential for over-treatment.
Dr Canfell said the combination of widespread HPV immunisation and screening would mean fewer women would be referred for further, unnecessary testing.
Self-collection not an option for all
Only a small minority of women will be able to collect an HPV sample themselves at a clinic to boost screening among underscreened demographics.
Only women aged over 30 who have declined cervical cancer screening and are two years or more overdue will be eligible.
Self collection will not be available until 2018.