Changes to Cervical Screening Program, HPV, Vaccination

February 6, 2017

Cervical screening program

Australia joins the ranks of HPV screening

It has been recognised for some time that cervical cancer is a rare outcome of persistent infection with one or more cancer-causing types of human papillomavirus (HPV) . In response to extensive research, the Australian National Cervical Screening Program will transition in 2017 from cytology-based screening every two years to HPV based screening every 5 years.

The changes

The time between tests will change from two to five years – if the HPV test result is negative, the patient will be recalled in 5 years for their next test. If the test is positive, the same sample will then proceed to liquid-based cytology (LBC) to determine if any cytological changes are apparent. The age at which screening starts will increase from 18 years to 25 years. Women will be invited to screen until they are 69 years of age, and will be invited to exit the program if they have a further negative HPV test between 70 and 74 years of age. To improve participation, self-collection of a cervical sample for HPV testing will also be available for under-screened or never-screened women.

CIN explained

There are two major types of cervical cancer: squamous cell carcinoma and adenocarcinoma. 70% of cases of cervical cancer are caused by HPV genotypes 16 and 18. Malignant transformation in the cervix usually occurs 10 to 20 years following infection with high-risk HPV types.

The changes that occur in the cervix as a result of HPV infection are referred to as cervical intraepithelial neoplasia (CIN). The majority of these changes regress, but a minority do progress to cervical cancer. The grading is as follows:

A unique Australian terminology system for squamous and glandular lesions called the Australian Modified Bethesda System has absorbed the previously used (but still reported) CIN classifications:

Other risk factors for progression to high-grade dysplasia and cancer include: persistence of HPV infection; age over 30 years; infection with multiple HPV types; immunosuppression and tobacco use. Recent attention has been given to the role the vaginal microbiome may play in the acquisition and persistence of HPV and subsequent development of cervical cancer. A healthy vaginal microbiome is typically colonised by certain members of the Lactobacillus species. A recent study showed that women with CIN have a more diverse Lactobacillus-depleted vaginal microbiome, compared with healthy women.

Vaccination program

Two HPV vaccines are available in Australia: a bivalent HPV vaccine (Cervarix®) that prevents HPV 16 and 18 and a quadrivalent HPV vaccine (Gardasil®) that prevents HPV 6, 11, 16, and 18. Both vaccines prevent HPV types that cause 70% of cervical cancers, with Gardasil®  preventing HPV types that cause 90% of genital warts. HPV vaccination is only of value in an individual when provided before infection with the vaccine targeted HPV types – it has no therapeutic effect on existing infections. The HPV vaccination Gardasil® is free for all males and females aged 12 to 13 years, and is available through school-based programs in all states and territories as part of the National Immunisation Program. An extremely important public health message is that vaccination does not cover all HPV types that may cause cervical lesions and cancer; therefore it is not a replacement for cervical screening.

The finding of CIN in any patient’s history should encourage vigilance and promote immune-enhancing strategies such as microbiota support – a strong and emerging evidence base supports such measures.

References available on request


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