In a real-world Swedish cohort of 28017 women, screening for cervical cancer using a DNA methylation-based tool, the WID-qCIN test, either alone or in combination with HPV16/18 genotyping, showed better performance than cytology in triaging HPV-positive women. The fact that this triage test does not rely on assessment of cellular morphology and can be performed purely on DNA, renders it suitable for screening strategies based on self-sampling.
The World Health Organization advocates for HPV-based screening using self-sampling as a simple strategy that could work also in resource-limited settings. High-performance molecular triaging strategies, such as the WID-qCIN test, which could be readily automated and do not require complex infrastructures, should further facilitate these efforts according to Dr. Martin Widschwendter of the European Translational Oncology Prevention and Screening Institute, Hall in Tirol, Research Institute for Biomedical Aging Research, Universität Innsbruck, Innsbruck, General Hospital Hall, Tirol Kliniken, Hall in Tirol, Austria; Department of Women’s Cancer, UCL EGA Institute for Women’s Health, University College London, London, UK; and Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden and colleagues who published the findings on 4 June 2024 in the Nature Medicine.
The authors wrote in the background that cytology-based cervical screening requires a complex infrastructure, well-trained workforce and short screening intervals. The proven superiority of testing for oncogenic HPVs as an objective and examiner-independent technique with high sensitivity and prolonged protection against cervical intraepithelial neoplasia (CIN) grade 2 or worse (CIN2+) has resulted in international guidelines recommending a transition from primary cytology-based to primary HPV-based screening.
Due to increased prevalence of HPV in women younger than 30 years of age leading to low specificity of HPV testing, primary HPV screening is only recommended in women at least 30 years of age. An HPV screen-positive result requires cytology-based triaging, so that only HPV- and cytology-positive women are referred for colposcopy and biopsy. In high-income countries, HPV-positive women typically undergo triaging with cytology. In contrast, patients positive for the main oncogenic HPV types are referred directly for colposcopy in the US.
However, at present, most HPV screening tests provide at least partial information on HPV genotypes. Emphasis is increasing to utilize the information on HPV16/18, indicating higher risk for disease progression, in the screening algorithm.
Cytology shows limited and highly variable sensitivity that has been observed to decrease over time. It requires equipment and expertise that differs from HPV testing, without being applicable for self-samples. The patients who test positive for HPV through self-sampling need to be reinvited for a separate cytology sample, potentially impacting attendance rates adversely. Therefore, improved strategies for triaging HPV-positive women are essential.
The proof of principle strategy to utilize DNA methylation tests on a non-cytological sample collected from the cervicovaginal region for detection of cervical (pre)cancer was demonstrated 20 years ago. Since then, several DNA methylation-based markers have been developed and applied in different settings, predominantly representing case–control studies or small cohort sets with fewer than a thousand volunteers.
Recently developed WID-qCIN test assesses DNA methylation across three regions of the human genes: DPP6, RALYL and GSX1. A preliminary assay validation was conducted in both a diagnostic and a predictive setting. In the article published in the Nature Medicine, the authors report that optimised the WID-qCIN test and applied it to HPV-positive women from a real-life population-based large cohort of the women, at least 30 years of age, having attended screening in Stockholm between 1 January and 31 March 2017. They assessed the predictive performance of the WID-qCIN test in combination with HPV16/18 genotyping compared with cytology to triage HPV-positive women.
In the analysis of all 2377 HPV-positive samples, a combination of WID-qCIN (with a predefined threshold) and HPV16/18 detected 93.4% of CIN grade 3 and 100% of invasive cervical cancers. The WID-qCIN/HPV16/18 combination predicted 69.4% of incident CIN grade 2 or worse compared with 18.2% predicted by cytology. The authors wrote that cytology or WID-qCIN/HPV16/18 triage would require 4.1 and 2.4 colposcopy referrals to detect one CIN grade 2 or worse during the 6 year period.
These findings support the use of WID-qCIN/HPV16/18 as an improved triage strategy for HPV-positive women. DNA methylation-based WID-qCIN test may complement HPV16/18 genotyping in triaging HPV-positive women with improved performance compared with widely used cytology. The fact that this triage test does not rely on assessment of cellular morphology and can be performed purely on DNA, renders it suitable for screening strategies based on self-sampling. The implementation of WID-qCIN in combination with HPV16/18 screening could help to overcome the issue of resampling patients for triaging after positive HPV results on self-samples.
This study received financial support from The Land Tirol and from the European Union’s Horizon 2020 Research and Innovation programme grant.
Reference
Schreiberhuber L, Barrett JE, Wang J, et al. Cervical cancer screening using DNA methylation triage in a real-world population. Nature Medicine; Published online 4 June 2024. DOI: https://doi.org/10.1038/s41591-024-03014-6