A new cervical screening began nationally on 1 December 2017. It will use an HPV DNA test rather than examining cervical cells on a microscope slide (Papanicolaou test). The sample is still collected from the cervix using a vaginal speculum to ensure accurate collection.
So from the point of view of the woman being screened, the process is the same. However because of greater accuracy, if negative, the screening interval will extend to five years. Practices will need to review their recall protocols to conform to the new program.
The program is based on an understanding that more than 99 per cent of cervical cancer is caused by HPV. This includes squamous cell and adenocarcinoma. A third type of cervical cancer, neuroendocrine or small cell cervical cancer, is often more aggressive, but accounts for less than 1 per cent of cervical cancers. Neither the Pap test nor the new Cervical Screening Test effectively detects neuroendocrine cancers.
All women who have symptoms still need investigation, regardless of when they were screened last.
The new test is reported to have 99 per cent accuracy in detecting the presence of HPV, an improvement over the current Pap test’s 85per cent (in detecting abnormal cells). The sample is collected either with the cervical sampler, or if a spatula is used, it must be with an endocervical brush.
The sampler is vigorously swished in the liquid, which is sent to pathology. The request is for CST (Cervical Screening Test). If anything else is on the form, it may not have the correct test, and may not attract a Medicare rebate.
If the sample is positive for HPV, the pathology provider will then do a cytology test and the HPV subtype will be identified. The management pathway uses both of these results.
HPV types 16 and 18 cause more than 70 per cent of cervical cancers in Australia. The current HPV vaccine protects against both these types; however, it does not protect against other oncogenic types of HPV known to cause cervical cancer. Therefore, vaccinated women are still at risk of cervical cancer from these other high risk HPV types and need to participate in regular cervical screening.
The new HPV vaccine will cover more subtypes, but it is still important for all women who have ever been sexually active to have cervical screening.
The lead time from HPV infection to cancer is 10-15 years, so first testing is now not until age 25. There is an exemption for women sexually exposed under the age of 14 years and/or prior to HPV immunisation. “Early sexual debut” must be noted on the request form.
There are also some higher risk groups for whom there are slightly different rules including those who are immunosuppressed or DES (diethylstilboestrol) exposed in utero.
In addition there is now the possibility of a self-collected specimen to screen for HPV. This test is a flock swab from the vagina collected by the woman herself. It will be helpful for women who are unable to have a vaginal speculum examination (vaginismus or post sexual assault for example). It is less accurate (85 per cent) compared with 99 per cent from a cervical specimen. It only attracts a Medicare rebate for under and never screened women. They must be ≥ 30 years of age and at least four years from last screen or never-screened and decline cervical sampling.
This MBS item can only be claimed once in a seven-year (84 months) period. If positive they will still need a cervical sample, but may be more willing to attempt this if the HPV test is positive.
The new CST only attracts a rebate every five years (57 months). If there are indications other than routine screening, this will need to be noted on the pathology request. Details can be found at cancerscreening.gov.au .
Online training available from NPS attracts CPD points.
From 2013-14 figures, only 57 per cent of women in the target age group participated in the screening program within the recommended two year window. This increased to 70 per cent for three years and 82 per cent for four years.
If we combine this with increased sensitivity of the test, even fewer women should be developing cervical cancer. The new test will be used as women are recalled for their screening two years from their last test. So all women will be using the new regime within two to three years. It is expected that this will reduce the nation’s rate of cervical cancer by a further 20-30 per cent.
As 80 per cent of cervical cancer occurs in unscreened or under-screened women, the highest yield will always be in those who are never or under-screened. In general practice, we may be able to recruit some of these women using the self-collected sample in the first instance.
The renewed cervical screening program