Screening Cervical Cancer: Factors Affecting Screening Coverage and Prevention
Introduction
In recent years there has been growing concerns about cervical screening attendance dropping to a 20-year low. Several efforts have been made to promote uptake of screening, including Public Health England (PHE) campaign âCervical Screening Saves Lives of 2019 and Jo's Cancer Trust, an organisation that has been encouraging women to engage with screening for many years and run a cervical cancer awareness week in June every year.
Reasons why we need to improve adherence to cervical screening
Since its creation in 1988, the NHS Cervical Screening Programme (NHSCSP) has decreased the number of women diagnosed with cervical cancer and reduced mortality from it. Screening saves about 5,000 lives a year and is the best protection against cervical cancer. It is not a test for cancer but a screening tool for conditions that could cause cancer in the future. It gives the possibility to prevent premalignant cells from becoming cancerous, providing treatment as soon as possible. In light of this, cervical cancer incidence is still troublingly high with nearly 9 women diagnosed a day and 2 dying every day. Screening detects about 220,000 abnormalities every year, which can be appropriately treated to prevent malignancy. As rates of attendance have been steadily declining it is concerning that these levels will increase further, leading to more morbidity and mortality from cervical cancer.
The biggest risk factor for developing invasive cervical cancer is non-attendance to screening. Screening prevents up to 70% of cancers, many who develop cancer have never been screened. With this knowledge, it is empirical to increase compliance with screening to prevent the avoidable morbidity and mortality. An understanding of why women arenât attending would enable change to be implemented to increase screening coverage to 80% target as set by NHSCSP. There has not been over 80% attendance since 2005. If increased even further to 85%, the number of cancer diagnoses could drop by 14% in one year, with deaths falling by 27% in 5 years time. Although over the years there has been a decrease in the rate of cervical cancer, there has been a worrying increase in the rate of cancer diagnosis in some age groups, particularly women aged 25-34 years old by 40%. There is a wide range of attendance throughout the UK, ranging from 55-82%, therefore it is essential that there be locally targeted interventions based on population needs8. If unable to increase attendance, the long-term modelling shows that cancer rates will increase, and by 2040 it could increase by 16% in 60-64 year-olds and 85% in 70-74 year-olds. It illustrates a possible 100% increase in mortality in those age groups if coverage falls by a further 5%.
The Screening Process
The NHSCSP offers all women with a cervix aged 25-49 an invitation to a smear every 3 years, and those aged 50-65 every 5 years. It involves a trained nurse, most commonly, to take a small sample of cervical cells which is sent to the lab for primary testing of HPV. If no HPV was present in the sample then no further testing was done. If the sample was HPV positive, then further analysis (cytology) into the cells present was completed. If any abnormal cells were detected, the patients would be sent to colposcopy for further assessment, possible biopsy and treatment.
Factors known to influence screening coverage
Poor educational levels are associated with low levels of cervical screening. The lowest levels of uptake to cervical screening was observed in women in the most deprived areas. In England, females in the most deprived quintile are 65% more likely to get cervical cancer when compared with the least deprived. Studies have shown that demographic groups associated with non-attendance are young, or over 50, ethnic minority groups and those of low socioeconomic backgrounds. Younger women are less likely to attend screening than their older counterparts 10 years previously. The main difference between the young and over 50s not attending is the young DNA (do not attend) appointments and the over 50s do not book an appointment in the first place. The North of England has worse baseline health when compared to the South, most likely due to a greater proportion of lower socioeconomic communities, who generally have poorer health literacy. The data collected in this audit has come from a GP surgery in Redcar, which is a highly deprived town on the North East coast of England. There have been many broad efforts to try and close the gap caused by socioeconomic inequalities and improve participation in cancer screening. However, it has not been enough the NHSCSP needs to change to incorporate advances that improve the service.
The issue is that women who do not respond to cervical screening invitations are a difficult group to influence, there isnэt a one size fits all approach. The UK is a diverse nation and needs varied approaches to increase coverage. There is a need for both national and local alterations to the way patients are invited and encouraged to engage with screening. Local populations will have differing needs, whether that was lower socioeconomic status, high levels of mental health issues, cultural differences or language barriers. Focused approaches from CCGs (clinical commissioning groups) and local authorities is needed to support the community. The studies discussed in the literature review have not addressed if there was any correlation between mental health issues and non-attendance. People with mental health issues are known to be likely to miss GP appointments and therefore this was recorded to see if it had any significance in this study.
History of the NHSCSP
The NHSCSP began in 1988. Before this, smears were taken opportunistically from 1964, and were not followed up adequately. Many women were over diagnosed and over treated with cone biopsies or full hysterectomies. A rise in deaths among under 35-year-olds from cervical cancer led to an increased awareness by doctors and the public to weaknesses in the current screening system. The department of health created a computerised call and recall system, originally to women aged 20-64 years old every 3-5 years. From 1990 GP surgeries were given incentives to achieve 80% compliance with the screening programme. This improved attendance from just 40% in the late 1980s to over 80% between 1991 and 1999. In the mid 1990s, the main limitations to the program were; too many low-grade abnormalities found, interobserver variability of smears, many having to undergo colposcopy due to repeated inadequate smears.
Testing Technologies
Liquid based cytology (LBC) was introduced in 2003, this allowed HPV triage. It significantly reduced the number of inadequate smears dropping from 9% to. The minimum age for screening was increased to 25 in 2005 as it was shown to have little to no benefit in women younger than 25. This was the same year that screening was standardised across the program, women aged 25-49 would be screened every 3 years and women 50-64 every 5 years, this was decided based on the data shown in figure. HPV primary testing is the most recent change to screening in 2019.
HPV testing has 3 roles; triage borderline and low-grade cervical abnormalities, test of cure post CIN (cervical intraepithelial neoplasia) treatment, and primary screening tool. A Cochrane review of HPV triage of borderline cytology better predicts the presence of high grade CIN than LBC. It has high sensitivity, designed to speed up referral to colposcopy, earlier treatment of precancerous cells, and post CIN treatment. Six months after CIN treatment, repeat cytology and HPV test is done. However, HPV status 6 months post treatment of high-grade dysplasia is of limited value for long term follow up as HPV can persist for some time even after CIN treatment. HPV is detected in 99% of cervical tumours22. The introduction of primary HPV screening has dramatically decreased the annual follow up samples needed in the long term. 80% of triage was HPV negative21-25. Testing for HPV could lead to the screening interval being extended between smears to 5-6 years. A pooled analysis of large trials showed that women who had been HPV screened had lower rate of cervical cancer than those with LBC alone. This led to large primary HPV testing pilot prior to its rollout in 2019.
It should be noted that there are issues with HPV screening as it has lower specificity when compared to LBC, especially in young women. However, the young women now entering screening age will have had the HPV vaccine so this should improve clinical utility of primary HPV screening in 25-30-year-olds. Consent is needed from every patient every time to test for HPV. It has slightly changed how samples are taken so better education with the new equipment is needed for adequate samples to be taken. There must be better explanation of the results and recall to patient if they have a query about what it means to be HPV positive. There are 1% of cervical cancers which are not HPV positive therefore with primary HPV screening 1% of pre-cancerous cells could be missed.
Screening Intervals
Evidence for intervals of cervical screening in varying age groups. Other countries, however, do use different screening intervals, America does smear tests every 3 years from 21-29 years old, and every 5 years from 30-65 years old. In Australia, they do smears from 25-74 years old, 10 years longer than in the UK. New Zealand recently have changed their minimum screening age from 20 to 25 in line with what was done in the UK in 2019.
In 2009, the UK's minimum age of screening was criticised and a major review was done. It concluded that based on evidence from a large number of women under 25, there was little benefit from being screened and treated. It is only when screening provides more benefits than harm that a screening programme is recommended. Infection with high risk human papillomavirus (hrHPV) was very common in people under 25 and may cause abnormal cell changes of the cervix (for most people these cervical abnormalities will normalise as the immune system irradiates the HPV infection)30. Screening women under the age of 25 would not save more lives, it would lead to thousands of extra unnecessary colposcopy and treatment of abnormal cells. However, there should be a low threshold to offer referral to secondary care in under 25s on a clinical basis. The number of younger people diagnosed with cervical cancer is likely to reduce due to the NHS HPV vaccination programme introduced in 2008.
Benefits of increasing compliance with screening
The NHS would benefit in multiple ways if it supported better uptake of screening. The average cost of a person diagnosed with stage 2 or later cervical cancer is £19,261, compared to those diagnosed stage 1a at just £1,3795. NHS England's Five Year Forward View calls for a radical upgrade in prevention. Having said this however, almost half of the local authorities have not attempted any interventions to promote attendance in the last 2 years, as well as nearly two thirds of the CCGs. There was a correlation between the highest smear attendance rates and most initiatives done to improve attendance, as seen in Yorkshire and Humber.
Reasons why women are not attending cervical smears
Jo's Cancer Trust provided information about the common reasons that people are not attending smears. The 2018 study showed a third did not attend due to embarrassment, negative body image, and low self-esteem. 25% thought they were healthy and did not need to attend. Some had feelings of discomfort around gynaecological exams, a lack of understanding of its importance, and 11% didn't ged 25-35 didn't realise they were in the highest risk group (61%). In 2016-17 1 in 4 DNA'd the appointment, which increased to 1 in 3 in 25-29 year-olds. Yet despite these findings, nearly all women (94%) said they would have a free test to prevent cancer if it was available, highlighting a lack of understanding about the role of screening.
These findings were also confirmed in another study from Sweden where women stated they had a positive attitude towards screening but other things were more important. They felt there was not adequate education and doctors did not encourage them to attend. The women agreed with the above; they felt healthy, had no symptoms, family history of cervical cancer and therefore did not need to attend. Embarrassment around gynaecological examinations was mentioned again as well as a fear of knowing the results of the test. Matters related to sickness and cancer were not on the forefront of young women's minds, it was found to be something that was not prioritised at this point in life.
Implementations that have been trialled to improve coverage
As mentioned previously young women are less likely to attend when compared to their counterparts 10 yers ago. This was thought to be due to women having children later in life, as women that have never had children have a 10% lower coverage rate. The case of Jade Goody dying from cervical cancer at 27, was the only thing that has increased coverage in under 30s, unfortunately this only lasted for 2 years after her death. From the STRATEGIC trial it was seen that women have a false sense of security from the HPV vaccination and believe they do not need to attend smears because of this. Therefore, HPV vaccination status was recorded in the study.
The STRATEGIC trial showed that the use of reminders was effective in increasing coverage. Only 30% of 25 year olds attend 6 months after initial invite. It was found that sending a specifically targeted leaflet to young women before their initial invite proved not to be effective with a p value of 0.747. They also allowed online booking of appointments, this also proved not to be effective with a p-value=0.802. Possibly a more individual approach is needed to engage young women. One intervention that was found to significantly improve compliance with smears was HPV self-testing, with an Odds ratio of 1.29. This intervention has made a significant difference as it eliminates the embarrassment of gynaecological examinations which has been expressed in all the literature reviewed as a main reason woman chose not to attend.
In a paper which investigated how deprivation affects the uptake of breast and cervical screening, it was shown that screening of cervical cancer in deprived areas were more resistant to change than in breast screening. It was thought this may be due to that in breast screening invitation you are given an appointment whereas cervical screening must remember to make your own appointment. It may be beneficial in cervical screening invitations to be given a date and time that you could change if unable to attend. Likewise, with the STATEGIC trial it was found that informative leaflets were not helpful in this group, unscreened individuals are much less likely to read a leaflet and more likely to be unengaged making uninformed decisions. Nonetheless this does differ from another study that states communities with poor education and literacy levels would benefit from the implementation of theory-based cervical cancer education to increase participation in screening.
Mental health and DNA of medical appointments
There is not much information on mental health conditions and nonattendance to specifically cervical smears. This was something this study hoped to address. There is information regarding cancer screening attendance and mental health issues. People with severe mental health conditions have similar cancer incidence to those without mental health issues, despite this they have increased mortality from cancer. The results of the study suggested this was because of decreased attendance to screening programmes and this may explain the discrepancy seen. Consequently, a population of people that must be better supported to attend screening are those with mental health conditions. Improved engagement with various cancer screenings in this disadvantaged group would aim to reduce their increased mortality from cancer.
In other studies, a link between young people with mental health issues and DNA'd GP appointments has been seen. In actual fact if someone DNAs an appointment it may signal a mental health problem, which applies whether or not the patient is known to have mental health problems in the past. With this information in mind, it was a factor of interest to research in this audit on cervical smears.
Interventions currently taking place to improve screening rates
In the year 2019-20, 72.2% of eligible women went to screening. In 2019, PHE launched âCervical Screening Saves Lives campaign to try and boost attendance, after data showed that attendance had fallen to a 20-year low. Some projects that have been implemented on a local level included work with local councils, using social media, displaying information in common public areas, targeted materials for people with learning disabilities, and working with faith groups to reach Black, Asian and minority ethnic groups. Increasing the accessibility to screening by doing early morning, late night, and weekend screening. Following up with people who DNA, providing training to all healthcare workers on how they can positively promote smears and encourage to signpost in other appointments. Providing leaflets on smears in languages commonly spoke in that area and access to interpreters. Practice cancer champions who would go through contacting non-attenders and create pop ups on SystemOne.
