Similarly, the screening programme has not been equitable for Pasifika and Asian women. Like Māori women, Pasifika women have lower screening rates and higher rates of cervical cancer incidence and mortality than European women. Asian women also have lower screening rates but lower incidence and similar mortality to European women.
Women who don’t access the screening programme are often referred to as “hard-to-reach” or “disengaged” but, in reality, the inequities are a systems issue. These groups are under-served and suffer the majority of cases of cervical cancer.
Our study explored whether self-testing would help the least-served groups. We show self-testing, particularly at home, raises screening rates among women who have never or rarely accessed the screening programme and experience the most barriers.
Clear preference for home testing
This is the first evaluation of the effectiveness of mailed self-testing kits for cervical cancer screening in Aotearoa New Zealand.
We invited Māori, Pasifika and Asian women between the ages of 30 and 69, who had never been screened or were more than five years overdue, to take part in a community-based, randomised controlled trial with three different tracks.
Our aim was to assess whether two invitation methods for self-testing improved screening participation over usual care (the third track). Women were either invited to take a self-test at their usual general practice or were mailed a kit to take a self-test at home.
We compared participation rates with the usual care process of an invitation to come to the GP clinic for collection of a standard Pap smear.
There were 3,553 women in the study. Although the absolute level of participation was modest, we showed that participation was statistically significantly higher for self-testing at home, compared to the usual Pap smear at the GP clinic.
Māori were 9.7 times more likely to agree to self-test at home. For Pasifika women, participation was six times more likely; for Asian women it was 5.1 times more likely.
Self-testing at the clinic was preferred, respectively 4.1, 3.3 and 1.6 times over the Pap smear. Overall, our results show access to screening at home is much preferred over other options.
A brief history of cervical cancer screening
Our understanding of cervical cancer goes back to the 1928 discovery by George Papanicolaou (hence Pap smear) of profound abnormalities in cervical cells. He realised this could be used as a method of early cancer diagnosis.
The process was subsequently refined in the 1950s after which the Pap smear was increasingly used for screening and early diagnosis.
By the 1970s, there was clear circumstantial evidence that cervical cancer was caused by a sexually transmitted agent, which was later identified as the human papillomavirus (HPV). This has allowed two crucial developments in the control of cervical cancer: effective vaccines with increasing coverage against high-risk HPVs and reliable screening using a vaginal swab.
From 2015, and increasingly around the world, vaginal samples (collected using a swab by women themselves or by healthcare professionals) have been used to identify the presence of HPVs with a high degree of reliability.
This screening approach does not need to involve any other person and has a number of advantages over a standard clinically obtained Pap smear. It allows collection at home and caters to those who prefer greater privacy or have less time. It is empowering because it places health management in a woman’s own hands.
This is an exact parallel with self-collected swabs for sexually transmitted infections (STIs), which are well accepted as standard of care. Self-testing for cervical cancer screening is increasingly available around the world.
The accuracy of HPV self-testing is similar to professionally taken samples and it improves participation. However, most studies have not targeted Indigenous or ethnic minority women. They remain under-served essentially everywhere.
How to ensure equity
Aotearoa New Zealand already has extensive experience with free mail-out screening for bowel cancer. Giving women the opportunity to self-test at home at no cost will result in the greatest impact toward improving equity of access to cervical cancer screening.
However, the National Cervical Screening Programme indicated that self-testing at home is not an option in their initial rollout of screening based on the detection of human papillomavirus (HPV), the leading cause of cervical cancer.
This will be a serious missed opportunity to improve equity. The key to achieving equity is for all women to access screening, including those who may agree only to testing at home.
This article is republished from The Conversation is the world's leading publisher of research-based news and analysis. A unique collaboration between academics and journalists. It was written by: John Donne Potter, Massey University and Naomi Brewer, Massey University.
John Donne Potter received funding from the Health Research Council of New Zealand for this work.
Naomi Brewer does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.