A new protocol for the analysis of self-collected cervical samples could reduce the need for follow-up clinician screening for many women, and result in more rapid referral for gynaecology assessment for others, improving NHS cervical cancer screening procedures.
Unlike clinician-collected samples, which are typically taken during a GP visit, self-samples can be taken at home. However, they cannot be processed using cytology, so if human papilloma virus (HPV) is found, a clinician-collected sample is required. This second sample is used to determine whether the patient needs immediate colposcopy, re-testing in 12 months, or whether the patient is already clear of the virus. Because 1 in 5 women with an HPV positive self-sample do not attend for clinician-sampling, there are concerns that this could lead to untreated cervical pre-cancer.
A team led by Wolfson Institute of Population Health (WIPH) researchers accessed details of self-sampled HPV test results that are not usually available for analysis, to estimate the risk of significant disease being present. Using these data, they were able to divide HPV-positive women into three groups: high-, medium-, and low-risk. Only 5% of women fell into the high-risk group, but about 40% of this group had disease that required treatment; they would be recommended for an immediate colposcopy. In this study, 53% of women testing positive fell into the low-risk group, and only 4% of them were found to have high-grade disease. It is suggested that this low-risk group could safely be re-tested after 12 months without the need for immediate clinician-sampling. This process could reduce the number of women recalled for clinician-collected sampling unnecessarily and allow others to be referred directly to secondary care.
Cervical cancer is one of the most preventable cancer types, but uptake of in-person screening offered through the NHS Cervical Screening Programme is at an all-time low. Self-sampling HPV tests that allow an individual to collect their own sample for cervical screening, rather than attend a clinic, are being explored as a way to increase uptake in screening. Recent WIPH-led research found that almost 70% of women would choose to self-sample if offered the choice. The UK National Screening Committee is consulting on offering the option of HPV self-sampling to under-screened people in the NHS cervical cancer screening programme.
Senior author and WIPH Professor of Cancer Epidemiology, Peter Sasieni, said: ‘Based on our analysis, we were able to recommend that it would be safe for the majority of women who had initially tested positive in their self-sample to be re-tested after 12 months, rather than have to have a further clinician-sampled screening test. This assessment of risk would reduce the numbers called unnecessarily for these clinician-based screening while still catching the vast majority of instances of cancer in their early stages. As some 20% of those under-screened still do not attend after a positive self-sample, this approach may be safer as well as being more acceptable.’
This study received funding from Cancer Research UK.
Jiayao Lei, Kate Cuschieri, Hasit Patel, Alexandra Lawrence, Katie Deats, YouScreen trial team, Peter Sasieni, Anita Lim. Human papillomavirus genotype and cycle threshold value from self-samples and risk of high-grade cervical lesions: a post-hoc analysis of a modified stepped-wedge implementation feasibility trial. PLOS MEDICINE 12 December 2024. https://doi.org/10.1371/journal.pmed.1004494