K. Miriam Elfström

Controlled trial of cervical cancer screening frequency among human‐papillomavirus‐vaccinated women

Abstract Cervical screening frequency has not been studied in vaccinees. As the major risk factor, oncogenic human papillomavirus (HPV) is declining due to vaccination. We report a trial to assess the effectiveness of cervical screening frequency among women HPV‐vaccinated as early adolescents (NCT02149030). In 2013, 5626 1992‐1995‐born women, who had received three doses of the HPV16/18 vaccine at ages 12–15 between 2007 and 2010 in a community‐randomized vaccination trial (NCT00534638), were allocated at age 22 into high‐intensity cytology‐based cervical screening by even birth date (Arm A1) or into low‐intensity cytology‐based cervical screening by odd birth date (Arm A2). One thousand three hundred thirty‐three women who received HPV16/18 vaccination at age 18 attended a safety of low intensity‐screening arm (Arm A3). Low‐intensity screening, where low‐grade cytological abnormalities were not revealed for 6 years, was compared to the standard high‐intensity screening used in Finland at the time. The prevalence of cytological and HPV findings was calculated at ages 22/25/28. The hazard ratio of histopathologically confirmed immediate cervical cancer precursors (HSIL/CIN2+) among participants was compared between low‐ and high‐intensity screening arms. The overall occurrence of CIN2+ was comparable in Arms A1, 0.70% and A2, 0.66%, with the corresponding hazard ratio at age 28 being 0.97 (95% confidence intervals, 0.50–1.88). By age 28, the occurrence of vaccine‐HPV types 16/18 was reduced up to 88% in the 12‐to‐15 compared to 18‐year‐old HPV‐vaccinated women. In conclusion, the risk of CIN2+ was similar for HPV‐vaccinated women who attended low‐intensity cervical screening compared to high‐intensity screening most likely due to the decline of oncogenic HPVs.

Cancer detection using human papillomavirus self‐sampling targeting long‐term non‐attenders in an organized cervical screening program

Abstract Self‐sampling for human papillomavirus (HPV) is an established strategy to increase participation in cervical screening. We previously reported a randomized trial targeting women who had not attended screening after >10 invitations, where sending of self‐sampling kits resulted in a 19% attendance and a positive predictive value (PPV) for high grade lesions (HSIL+) of 40%, despite no triaging after the HPV test. Because of the striking results, the intervention was extended to all women resident in Stockholm County, Sweden, in the years 2019/20, who had not attended screening >10 years ( N  = 42,409). Participation was 35.6% and 11.6% of the participating women were HPV‐positive. Among these, there were 43 cases of invasive cervical cancer and 319 cases of high‐grade lesions. The PPV was particularly high for HPV16/18 positive women (12% for invasive cancer and 59% for HSIL). In summary, participation with HPV self‐sampling among long‐term non‐attenders in the real‐life program was considerably higher than in the research setting and the high yield of HSIL+ implied high effectiveness.

Population-Based Age-Period-Cohort Analysis of Declining Human Papillomavirus Prevalence

Abstract Background Most countries in the world have launched human papillomavirus (HPV) vaccination programs, and declining HPV prevalences are reported. We aimed to disentangle the influences of calendar time, birth cohort, and age by analyzing HPV prevalences in the population-based cervical screening program using age-period-cohort modeling. Methods All 813 882 primary HPV-based cervical screening tests from women aged 23–64 years between 2014 and 2023 in the capital region of Sweden were identified in the Swedish National Cervical Screening Registry. The odds ratio (OR) of HPV-16/18 infection was estimated comparing birth cohorts to the unvaccinated 1984-born using an age-period-cohort model. The impact of changing HPV prevalences on the number needed to screen (NNS) to detect and prevent 1 cervical cancer case was calculated. Results HPV vaccination coverage was 82%–83% among women born in 1999–2000. Before 2019, the HPV-16/18 prevalence was highest among the youngest women. During 2020–2023 the prevalence consistently decreased among the birth cohorts offered organized school-based vaccination. There was a 98% decline in HPV-16 prevalence (OR, 0.02 [95% confidence interval {CI}, .01–.04]) and a 99% decline in HPV-18 prevalence (OR, 0.01 [95% CI, .00–.04]) among the 2000-born compared to the 1984-born. The declining HPV-16/18 prevalences resulted in major increases in the NNS to detect and to prevent 1 case of cervical cancer. Conclusions The declines of HPV-16/18 were considerably larger than the vaccination coverage, suggesting herd immunity. The changing epidemiology of HPV types impacts screening needs, necessitating updated screening programs.

Evaluation of primary HPV-based cervical screening among older women: Long-term follow-up of a randomized healthcare policy trial in Sweden

Background Evidence on invasive cervical cancer prevention among older women is limited, especially with the introduction of human papillomavirus (HPV)-based screening and longer interval. We conducted a long-term follow-up of the first phase of a randomized healthcare policy trial in cervical screening, targeting women aged 56 to 61 years old, to investigate the effectiveness of primary HPV-based screening in preventing invasive cervical cancer (ICC) and the safety of extending screening interval. Methods and findings The randomized healthcare policy trial of primary HPV-based cervical screening targeted women residing in Stockholm-Gotland region during 2012 to 2016, aged 30 to 64 years. The trial aimed to investigate the detection rate of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) within 24 months and long-term protection against invasive cervical cancer, comparing primary HPV-based screening to primary cytology-based screening. The initial phase of the trial, which was the focus of this study, targeted women aged 56 to 61 years old in 2012 to 2014 who were randomized to primary cytology arm (n = 7,401) or primary HPV arm (n = 7,318). We used national registries to identify the subsequent cervical tests and all histopathological diagnoses including ICC before December 31, 2022. We calculated cumulative incidence, incidence rate (IR) and IR ratio (IRR) of ICC, by baseline test result. Furthermore, we calculated longitudinal sensitivity and specificity for detecting cervical intraepithelial neoplasia grade 2 or worse (CIN2+) by receipt of primary cytology or primary HPV test for the recommended screening intervals in this age group. We found that the IR of ICC among women in the primary HPV arm was 7.2/100,000 person-years (py) and 3.0 for women who tested HPV negative, compared to 18.4/100,000 py among women in the primary cytology arm and 18.8 for women who tested cytology negative. We further found that the overall point estimate for the risk of ICC over 10 years of follow-up among women in the primary HPV arm was 0.39 compared to women in the primary cytology arm, but this was not statistically significant (IRR: 0.39; 95% confidence interval, CI [0.14, 1.09]; p = 0.0726). However, among women with a negative test result at baseline, women in the primary HPV arm had an 84% lower risk of ICC compared to women in the primary cytology arm (IRR: 0.16; 95% CI [0.04, 0.72]; p = 0.0163). Moreover, primary HPV testing had a higher sensitivity for detecting CIN2+ within a 7-year interval than primary cytology testing within a 5-year interval (89.6% versus 50.9%, p < 0.0001). We were limited by a partial imbalance of invitations during the follow-up between the 2 arms which may have led to an underestimation of the effectiveness of primary HPV-based screening. Conclusions In this study, we observed that women over 55 years of age who received a primary negative HPV test result had substantially lower risk of CIN2+, and ICC, compared to women who received a primary negative cytology result. This should apply even if the screening interval were prolonged to 7 years. Trial Registration NCT01511328.

Nationwide registry‐based trial of risk‐stratified cervical screening

AbstractIn 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.

Baseline findings and safety of infrequent vs. frequent screening of human papillomavirus vaccinated women

Less frequent cervical cancer screening in human papillomavirus (HPV) vaccinated birth cohorts could produce considerable savings without increasing cervical cancer incidence and loss of life‐years. We report here the baseline findings and interim results of safety and accuracy of infrequent screening among HPV16/18 vaccinated females. The entire 1992–1994 birth‐cohorts (30,139 females) were invited to a community‐randomized HPV16/18‐vaccination trial. A total of 9,482 female trial participants received HPV16/18‐vaccination in 2007–2009 at age of 13–15. At age 22, 4,273 (45%) of these females consented to attend a randomized trial on frequent (ages 22/25/28; Arm 1: 2,073 females) vs. infrequent screening (age 28; Arm 2: 2,200 females) in 2014–2017. Females (1,329), who had got HPV16/18 vaccination at age 18 comprised the safety Arm 3. Baseline prevalence and incidence of HPV16/18 and other high‐risk HPV types were: 0.5% (53/1,000 follow‐up years, 104) and 25% (2,530/104) in the frequently screened Arm 1; 0.2% (23/104) and 24% (2,413/104) in the infrequently screened Arm 2; and 3.1% (304/104) and 23% (2,284/104) in the safety Arm 3. Corresponding prevalence of HSIL/ASC‐H and of any abnormal cytological findings were: 0.3 and 4.2% (Arm 1), 0.4 and 5.3% (Arm 2) and 0.3 and 4.7% (Arm 3). Equally rare HSIL/CIN3 findings in the infrequently screened safety Arm A3 (0.4%) and in the frequently screened Arm 1 (0.4%) indicate no safety concerns on infrequent screening despite the up to 10 times higher HPV16/18 baseline prevalence and incidence in the former.

Cervical cancer case–control audit: Results from routine evaluation of a nationwide cervical screening program

Our study used a refined case–control cervical cancer Audit framework to investigate effectiveness of cervical screening, with measures of three screening failures: irregular‐participation, cervical cancer developed after cytological abnormalities and after normal screening results. The register‐based study included 4,254 cervical cancer cases diagnosed in Sweden during 2002–2011, and 30 population‐based controls per case. We used conditional logistic regression models to examine relative risks of cervical cancer in relation to screening participation and screening results in the past two screening rounds from 6 months before cancer diagnosis. We found that women unscreened in past two screening rounds showed four times increased risk of cervical cancer compared to women screened in time (OR = 4.1, 95% CI = 3.8–4.5), and women unscreened in the previous round but screened in the most recent round also showed a statistically significantly elevated risk (OR = 1.6, 95% CI = 1.5–1.8). Women having abnormality in previous two rounds exhibited higher risk of cervical cancer compared to women screened with normal results, while having normal results in the subsequent round after the abnormality also yielded an increased risk (OR = 4.0, 95% CI = 3.2–5.1). Being screened with only normal results was associated with 89% risk reduction for squamous cell cancer, compared to women unscreened, but only 60% reduction for adenocarcinoma. Our findings emphasize the importance of routine participation in cervical screening and suggest that management of abnormalities, as well as sensitivity of the test, warrants improvement especially for preventing cervical adenocarcinoma. The Audit framework serves as routine evaluation model and the findings benchmark for future evaluation of changes in screening practice.

Human Papillomavirus Infection Determines Prognosis in Cervical Cancer

PURPOSE Detection of human papillomavirus (HPV) by polymerase chain reaction in invasive cervical cancer is strongly associated with prognosis but previous studies have not considered sequencing efforts. We aimed to assess the association when also including comprehensive analysis of HPV infection by deep sequencing and a longer follow-up period. MATERIALS AND METHODS We subjected all 392 of 2,845 invasive cervical cancer cases that were polymerase chain reaction–negative for HPV to RNA sequencing on the NovaSeq 6000 platform (Illumina) and identified an additional 169 cases as HPV-positive. We followed all women from date of diagnosis to December 31, 2016, emigration, or death, whichever occurred first. The main outcome was all-cause mortality by December 31, 2016. We calculated 5-year cumulative relative survival ratios compared with the female general population and used Poisson regression to estimate excess hazard ratios of all-cause mortality by infection with any of the 13 most oncogenic (high-risk [hr]) HPV types in the tumor. All models were adjusted for age, time since diagnosis, stage, histology, and education level. RESULTS The 5-year cumulative relative survival ratio was 0.45 (95% CI, 0.39 to 0.51) in the hrHPV-negative group, and 0.74 (95% CI, 0.72 to 0.75) in the hrHPV-positive group. This translated to a statistically significantly 43% lower excess mortality in the hrHPV-positive group compared with the hrHPV-negative (corresponding to an excess hazard ratio 0.57; 95% CI, 0.48 to 0.69). There was no association between HPV risk group, clade, or number of HPV infections and prognosis. CONCLUSION hrHPV status is a strong determinant of cervical cancer prognosis over 15 years after diagnosis, above and beyond other established factors.

Scientific approaches toward improving cervical cancer elimination strategies

AbstractAt 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.

Screening for Early Cervical Cancer Detection

This study is to audit results and adherence to Cervical Screening program before and after the implementing awareness of the WHO guidelines of screening among the multidisciplinary healthcare workers and patients.

Research Project on Reminders and Self-Sampling Can Increase Participation in Gynecology Cell Sampling - Preventive Examination Against Cervical Cancer.

Prevention of cervical cancer with cervical screening is one of the most successful screening activities in medicine. In Sweden, screening was implemented in the 1960s and has since prevented tens of thousands of women from having cervical cancer. Individual invitations to screening result in increased attendance therefore evaluating strategies for reaching women through invitations is particularly valuable. Women who regularly attend screening following an invitation reduce their risk of cervical cancer by as much as 90%. Of the women who are diagnosed with cervical cancer (about 550 women per year in Sweden), as many as 38% did not participate in the screening. Invitations for screening are sent to the entire population in Sweden aged 23-70. The current coverage of screening is 82.9%, which represents the proportion of women ages 23-70 who attend according to recommendations. In addition, many women are sporadic attenders who reduce their risk for cancer somewhat. The highest cancer risk is seen among those women who have never participated as well as women who have had a history of precancerous lesions or HPV infection but have not been followed-up. Cervical cancer is the first form of cancer for which there are approved molecular screening tests (HPV test). Unlike the older screening method (cytology), self-collected samples can be analyzed for HPV (the analysis method is so sensitive that it does not matter if the sample is not optimally taken). Invitations and reminders about cervical screening are sent by letter to the woman's home address (about 3 million letters per year in Sweden). This strategy results in a waste of resources and has a negative environmental impact. Regarding reminders, we have seen in previous research that the effect is not optimal. When sending a physical reminder letter to women who have not participated in more than 10 years (current routine), only 2% of the women invited came for sampling. Reminders with SMS are now standard for many businesses in society, such as car testing or dental appointments. It is inexpensive, saves the environment and there are studies that suggest it is more effective than sending physical letters. In this study, we intend to investigate whether SMS reminders, electronic letters, and physical letters for screening lead to increased participation and thus to a higher proportion of detected, treatable precursors of cervical cancer compared to before.

Randomized Implementation of Primary HPV Testing in the Organized Screening for Cervical Cancer in Stockholm

The purpose is to evaluate whether implementation of primary human papillomavirus (HPV) screening in the screening programme for cervical cancer improves the programme in terms of better cancer protection and better cost efficiency.