Long-term follow-up of cervical cancer incidence after normal cytological findings.

An increase in cervical cancer incidence in Sweden from 2014 to 2015 has been attributed to an increase in false-negative cytological findings before cancer diagnoses. Years later, we performed a long-term follow-up to investigate whether the problem persisted. At each calendar year from 2016 to 2020, we identified women with prior normal cervical screening results through linkage to the Swedish National Cervical Screening Registry. We reported their incidence rates (IRs) of invasive cervical cancer in consecutive years and compared the IRs over time. For the years 2016 to 2020, there was no overall change in cervical cancer incidence after two normal cytology in the last two screening intervals. However, there was a further 62% increase among women 50 to 60 years of age with normal cytology in the past two screening intervals. The incidence rate of cervical cancer was high among nonscreened women and low among HPV-screened women with negative results, with no trends over time. Our results imply that the previously reported decrease in sensitivity of cervical cytology is persisting. Although primary cytology screening is no longer used, cytology is used in triaging among HPV-positive women. Our findings suggest that improved triaging is needed, for example, improved quality assurance and/or use of alternative triage tests.

Nationwide registry-based trial of risk-stratified cervical screening.

In well-screened populations, most cervical cancers arise from small groups of women with inadequate screening. The present study aims to assess whether registry-based cancer risk assessment could be used to increase screening intensity among high-risk women. The National Cervical Screening Registry identified the 28,689 women residents in Sweden who had either no previous cervical screening or a screening history indicating high risk. We invited these women by SMS and/or physical letter to order a free human papillomavirus (HPV) self-sampling kit. The Swedish national HPV reference laboratory performed extended HPV genotyping and referred high-risk HPV-positive women to their regional gynecologist. A total of 3691/28,689 (12.9%) women ordered a self-sampling kit and 10.0% (2853/28,689) returned a sample for testing. Participation among women who had never attended screening was low, albeit improved. Up to 22.5% of women in other high-risk groups attended. High-risk HPV types were detected in 8.3% of samples. High-risk HPV-positive women (238/2853) were referred without further triaging and severe cervical precancer or cancer (HSIL+) in histopathology were detected in 36/158 (23%) of biopsied women. Repeat invitations gave modest additional participation. Nationwide contacting of women with high risk for cervical cancer with personal invitations to order HPV self-sampling kits resulted in high yield of detected CIN2+. Further efforts to improve risk-stratified screening strategies should be directed to improving (i) the precision of the risk-stratification algorithm, (ii) the convenience for the women to participate and, (iii) ensuring that screen-positive women are followed-up.

Scientific approaches toward improving cervical cancer elimination strategies.

At the 2023 EUROGIN workshop scientific basis for strategies to accelerate the elimination of cervical cancer and its causative agent, human papillomavirus (HPV) were reviewed. Although some countries have reached key performance indicators toward elimination (>90% of girls HPV vaccinated and >70% of women HPV screened), most are yet to reach these targets, implying a need for improved strategies. Gender-neutral vaccination, even with moderate vaccination coverage was highlighted as a strategy to achieve elimination more rapidly. It is more resilient against major disturbances in vaccination delivery, such as what happened during the coronavirus pandemic. Further, an analysis of ethical/legal issues indicated that female-restricted vaccination is problematic. Extended catch-up of vaccination with concomitant screening, and outreach to vulnerable groups were highlighted. Although birth cohorts with high coverage of HPV vaccination at school are protected against HPV, and HPVs have a very low reproductive rate in women above age 35, adult women below age 30 have inadequate direct protection. In addition to herd protection from gender-neutral vaccination, this group can be protected by offering concomitant catch-up HPV vaccination and HPV screening. Furthermore, hepatitis B vaccination experiences indicate that elimination cannot be achieved without prioritizing vulnerable/migrant populations. The long-lasting durability of vaccination-induced antibody responses suggests prolonged protection with HPV vaccines when adequately administrated. Finally, cost-effectiveness modelling suggests that high-coverage HPV vaccination in multiple population segments will be resource-saving due to reduced need for screening. In summary, the workshop found that strategically optimal deployment of vaccination will accelerate elimination of HPV and cervical cancer.

Low methylation marker levels among human papillomavirus-vaccinated women with cervical high-grade squamous intraepithelial lesions.

Cervical cancer screening programs, including triage tests, need redesigning as human papillomavirus (HPV)-vaccinated women are entering the programs. Methylation markers offer a potential solution to reduce false-positive rates by identifying clinically relevant cervical lesions with progressive potential. In a nested case-control study, 9242 women who received the three-dose HPV16/18-vaccine at ages 12-15 or 18 in a community-randomized trial were included. Subsequently, they were re-randomized for either frequent or infrequent cervical cancer screening trials. Over a 15-year post-vaccination follow-up until 2022, 17 high-grade squamous intraepithelial lesion (HSIL) and 15 low-grade (LSIL) cases were identified at the 25-year screening round, alongside 371 age and community-matched HPV16/18-vaccinated controls. Methylation analyses were performed on cervical samples collected at age 25, preceding histologically confirmed LSIL or HSIL diagnoses. DNA methylation of viral (HPV16/18/31/33) and host-cell genes (EPB41L3, FAM19A4, and miR124-2) was measured, along with HPV-genotyping. No HPV16/18 HSIL cases were observed. The predominant HPV-genotypes were HPV52 (29.4%), HPV59/HPV51/HPV58 (each 23.5%), and HPV33 (17.7%). Methylation levels were generally low, with no significant differences in mean methylation levels of viral or host-cell genes between the LSIL/HSIL and controls. However, a significant difference in methylation levels was found between HSIL cases and controls when considering a combination of viral genes and EPB41L3 (p value = .0001). HPV-vaccinated women with HSIL had HPV infections with uncommon HPV types that very rarely cause cancer and displayed low methylation levels. Further investigation is warranted to understand the likely regressive nature of HSIL among HPV-vaccinated women and its implications for management.

Divergent effects of switching from cytology to HPV-based screening in the Nordic countries.

BACKGROUND: Cervical cytology has been the primary method of cervical cancer screening for decades. Tests that detect viral HPV are shown in several randomized trials to provide better protection against cancer compared with cytology. HPV-based screening has been implemented alongside cytology in the Nordic countries for several years. The aim of this study was to compare cytology and HPV-based screening in the colposcopy referrals and detection rates of cervical lesions. METHODS: Individual-level screening data from Finland, Iceland, Norway and Sweden were harmonized and aggregated locally. We utilized data for tests taken during years 2015-17 and biopsies taken during years 2015-19 to allow 24 months of follow-up. Age-standardized estimates and age-adjusted risk ratios for six different outcomes of screening management were calculated. RESULTS: The age-standardized colposcopy rates were higher in HPV-based testing compared with cytology in Finland (3.5% vs. 0.9%) and Norway (6.0% vs. 4.1%) but lower in Sweden (3.7% vs. 4.9%). The relative detection rate of cervical intraepithelial neoplasia grade 2 and above in HPV-based testing compared with cytology was highest in Finland (RR 2.37, 95% CI 2.13-2.63) and Norway (RR 1.66, 95% CI 1.57-1.72) while in Sweden the difference was not statistically significant (RR 0.98, 95% CI 0.95-1.00). CONCLUSIONS: The effects of implementing HPV screening varied by country as different screening algorithms were implemented. HPV-based screening increases colposcopy rates mainly through referrals from increased repeat testing and detection rate is therefore significantly higher compared with cytology. Monitoring of these indicators in subsequent rounds of HPV-based screening remains essential.

The International Human Papillomavirus Reference Center: Standardization, collaboration, and quality assurance in HPV research and diagnostics.

The International Human Papillomavirus (HPV) Reference Center (IHRC) confirms and assigns type numbers to novel HPV types, maintains a reference clone repository, and issues international proficiency panels for HPV screening and genotyping. Furthermore, the Center coordinates the Global HPV Reference Laboratory Network that promotes collaboration and international exchange of experiences among national HPV reference laboratories, to further international standardization and quality assurance in the HPV field. The established HPV types (n = 225) belong to 5 different genera: alpha (n = 65), beta (n = 54), gamma (n = 102), mu (n = 3) and nu (n = 1). Since the last published IHRC overview in 2018, 6 novel types have been established, with 5/6 belonging to the gamma genus and 1/6 to beta genus. Also, 474 reference clones have been provided to 55 different research laboratories and the global proficiency program for HPV genotyping has seen an increasing proficiency (despite a decrease seen in 2019), from 68% proficiency in 2017 to 77.3% in 2022. The first proficiency study for HPV screening found an international proficiency of up to 77%. In summary, increasing complexity of the HPVs and demands on quality assurance in the era of cervical cancer elimination requires international efforts to support proficiency and recognized quality and order among HPV types.

[Human papillomavirus type 18 - In memoriam]. / Minnesord över humant papillomvirus typ 18.

HPV 18 caused 19 percent of all cervical cancer cases in Sweden, in particular adenocarcinomas. High vaccination coverages are required to eliminate the most oncogenic HPV types like HPV 16 and HPV 18, while medium-oncogenic viruses such as HPV 31, 33, 45, 52, and 58 are easier to eliminate due to their lower reproduction number. Women born 1994-1998 were offered catch-up vaccination against HPV 16 and HPV 18 at ages 13-18, but only about 55 percent participated, which is insufficient to eliminate these viruses. Offering vaccination against HPV 16, 18, 31, 33, 45, 52, and 58 to women born in 1994-1998 and achieving around 70 percent participation should eliminate the medium-oncogenic viruses and achieve population immunity also for HPV 16/18. A national project offering free vaccines and screening against these HPV types is ongoing since 2021. Already at the start of the project, there was only a single case of HPV 18 in age groups with high vaccination coverage, implying that extinction of this virus is imminent.

The Swedish Cervical Screening Cohort.

The Cervical Screening Cohort enrols women screened for human papillomavirus (HPV) and cervical abnormalities within the capital region of Sweden from the organised screening program and the non-organised testing of cervical samples. The cohort started in 2011 and has enrolled more than 670,000 women, contributing with more than 1.2 million biobanked samples. The cohort is systematically updated with individual-level data from the Swedish National Cervical Screening Registry (NKCx). Key variables include birthdate, sampling date, cytological, histopathological and HPV analysis results, and invitation history. Each sampling and subsequent clinical follow-up is sequentially registered, allowing for longitudinal analyses of screening results and associated results of the clinical workup. The cohort is ideal for longitudinal, long-term follow-up studies due to its validated documentation and registry-derived information. From the data, it is possible to penetrate important human health mechanisms. The data are available as open-data and GDPR-compliant. Samples are available after getting the required permissions. Results will help researchers understand factors that increase cancer risk and other diseases.

Cervical cancer screening using DNA methylation triage in a real-world population.

Cervical cancer (CC) screening in women comprises human papillomavirus (HPV) testing followed by cytology triage of positive cases. Drawbacks, including cytology's low reproducibility and requirement for short screening intervals, raise the need for alternative triage methods. Here we used an innovative triage technique, the WID-qCIN test, to assess the DNA methylation of human genes DPP6, RALYL and GSX1 in a real-life cohort of 28,017 women aged ≥30 years who attended CC screening in Stockholm between January and March 2017. In the analysis of all 2,377 HPV-positive samples, a combination of WID-qCIN (with a predefined threshold) and HPV16 and/or HPV18 (HPV16/18) detected 93.4% of cervical intraepithelial neoplasia grade 3 and 100% of invasive CCs. The WID-qCIN/HPV16/18 combination predicted 69.4% of incident cervical intraepithelial neoplasia grade 2 or worse compared with 18.2% predicted by cytology. Cytology or WID-qCIN/HPV16/18 triage would require 4.1 and 2.4 colposcopy referrals to detect one cervical intraepithelial neoplasia grade 2 or worse, respectively, during the 6 year period. These findings support the use of WID-qCIN/HPV16/18 as an improved triage strategy for HPV-positive women.

Seroepidemiological assessment of the spread of SARS-CoV-2 among 25 and 28 year-old adult women in Finland between March 2020-June 2022.

INTRODUCTION: Serological surveys of the prevalence of SARS-CoV-2 are instrumental to understanding the course of the COVID-19 epidemic. We evaluate the seroprevalence of SARS-CoV-2 among young adult Finnish females residing in 25 communities all over Finland from 2020 until 2022. METHODS: Between 1st March 2020 and 30th June 2022, 3589 blood samples were collected from 3583 women born in 1992-95 when aged 25 or 28 years old attending the follow-up of an ongoing population-based trial of cervical screening strategies. The crude and population standardized SARS-CoV-2 seroprevalence was measured using nucleocapsid (induced by infection) and spike wild-type (WT) protein (induced both by infection and by vaccination) antigens over time and stratified by place of residence (inside or outside the Helsinki metropolitan region). RESULTS: During 2020 (before vaccinations), spike-WT and nucleocapsid IgG antibodies followed each other closely, at very low levels (<5%). Spike-WT seropositivity increased rapidly concomitant with mass vaccinations in 2021 and reached 96.3% in the 2nd quartile of 2022. Antibodies to nucleocapsid IgG remained relatively infrequent throughput 2020-2021, increasing rapidly in the 1st and 2nd quartiles of 2022 (to 19.7% and 56.6% respectively). The nucleocapsid IgG seropositivity increased more profoundly in participants residing in the Helsinki metropolitan region (4.5%, 8.4% and 43.9% in 2020, 2021 and 2022 respectively) compared to those residing in communities outside the capital region (4.5%, 4.3% and 34.7%). CONCLUSIONS: Low SARS-CoV-2 infection-related seroprevalence during 2020-2021 suggest a comparatively successful infection control. Antibodies to the SARS-CoV-2 WT spike protein became extremely common among young women by the end of 2021, in line with the high uptake of SARS-CoV-2 vaccination. Finally, the rapid increase of seroprevalences to the SARS-CoV-2 nucleocapsid protein during the first and second quartile of 2022, imply a high incidence of infections with SARS-CoV-2 variants able to escape vaccine-induced protection.

Lack of detectable HPV18 antibodies in 14% of quadrivalent vaccinees in a longitudinal cohort study.

Although HPV vaccines are highly efficacious, a notable proportion of quadrivalent vaccinees are HPV18 seronegative post-vaccination. We have investigated this findings' validity by comparing vaccine-induced antibody responses using two different immunoassays. 6558 16-17-year-old females participated in the FUTURE II (NCT00092534) and PATRICIA (NCT00122681) trials in 2002-2004. Both the quadrivalent and bivalent vaccine recipients (QVR and BVR) received three doses. Twelve-year follow-up for 648 vaccinees was conducted by the Finnish Maternity Cohort. The presence of neutralising and binding HPV antibodies was analysed via HPV pseudovirion-based neutralisation and pseudovirion-binding assays. Four percent and 14.3% of the QVRs were seronegative for neutralising and binding antibodies to HPV16 and HPV18, respectively. No BVRs were HPV16/18 seronegative post-vaccination. The antibody titres were strongly correlated between the assays, Pearson's correlation coefficient, r[HPV16] = 0.92 and 0.85, and r[HPV18] = 0.91 and 0.86 among the QVRs and BVRs respectively. Fourteen percent of QVRs lacked detectable HPV18 antibodies in long-term follow-up.

Concomitant human papillomavirus (HPV) vaccination and screening for elimination of HPV and cervical cancer.

HPV vaccination with concomitant HPV-based screening of young women has been proposed for faster cervical cancer elimination. We describe the baseline results of a population-based trial of this strategy to reduce the incidence of HPV. All 89,547 women born 1994-1999 and resident in the capital region of Sweden were personally invited to concomitant HPV vaccination and HPV screening with 26,125 women (29.2%) enrolled between 2021-05-03 and 2022-12-31. Baseline HPV genotyping of cervical samples from the study participants finds, compared to pre-vaccination prevalences, a strong decline of HPV16 and 18 in birth cohorts previously offered vaccination, some decline for cross-protected HPV types but no decline for HPV types not targeted by vaccines. Our dynamic transmission modelling predicts that the trial could reduce the incidence of high-risk HPV infections among the 1994-1998 cohorts by 62-64% in 3 years. Baseline results are prevalences of HPV infection, validated transmission model projections, and power estimates for evaluating HPV incidence reductions at follow-up (+/-0.1% with 99.9% confidence). In conclusion, concomitant HPV vaccination and HPV screening appears to be a realistic option for faster cervical cancer elimination. Clinicaltrials.gov identifier: NCT04910802; EudraCT number: 2020-001169-34.

Human papillomavirus negative high grade cervical lesions and cancers: Suggested guidance for HPV testing quality assurance.

BACKGROUND: Some high-grade cervical lesions and cervical cancers (HSIL+) test negative for human papillomavirus (HPV). The HPV-negative fraction varies between 0.03 % and 15 % between different laboratories. Monitoring and extended re-analysis of HPV-negative HSIL+ could thus be helpful to monitor performance of HPV testing services. We aimed to a) provide a real-life example of a quality assurance (QA) program based on re-analysis of HPV-negative HSIL+ and b) develop international guidance for QA of HPV testing services based on standardized identification of apparently HPV-negative HSIL+ and extended re-analysis, either by the primary laboratory or by a national HPV reference laboratory (NRL). METHODS: There were 116 initially HPV-negative cervical specimens (31 histopathology specimens and 85 liquid-based cytology samples) sent to the Swedish HPV Reference Laboratory for re-testing. Based on the results, an international QA guidance was developed through an iterative consensus process. RESULT: Standard PCR testing detected HPV in 55.2 % (64/116) of initially "HPV-negative" samples. Whole genome sequencing of PCR-negative samples identified HPV in an additional 7 samples (overall 61.2 % HPV positivity). Reasons for failure to detect HPV in an HSIL+ lesion are listed and guidance to identify cases for extended re-testing, including which information should be included when referring samples to an NRL are presented. CONCLUSION: Monitoring the proportion of and reasons for failure to detect HPV in HSIL+ will help support high performance and quality improvement of HPV testing services. We encourage implementation of QA strategies based on re-analysis of "HPV negative" HSIL+ samples.