Promising strategies for cervical cancer screening in the post-human papillomavirus vaccination era

Human papillomavirus persistence or clearance after infection in reproductive age. What is the status? Review of the literature and new data of a vaginal gel containing silicate dioxide, citric acid, and selenite

Cervical cancer, the third most common cancer in women, is caused in nearly all cases by a persistent infection with high-risk types of the human papillomavirus. Although human papillomavirus infections are 80%-90% transient and disappear spontaneously within 24 months, human papillomavirus infections that remain are at risk of developing cervical lesions. Different therapeutical approaches have been tested to promote the regression of low-grade lesions or prevent progression. They include the application of 5-fluorouracil, curcumin, imiquimod, interferons, Vitamin D, and others. Also, the effect of probiotics and vaginal therapy with carboxy-methyl-beta glucan was assessed. Review of the literature and presentation of the last study data are presented. Clearance of high-risk human papillomavirus seemed to be promoted by treatment with a new vaginal gel containing a highly disperse SiO₂ and an anti-oxidative combination of citric acid and sodium. This gel showed, after 6 months, an improvement of cytological Pap findings (ASC-US, LSIL, ASC-H, or HSIL) in 80.9% of the participants. Similarly, there was a clearing of hr-human papillomavirus in 53% of cases after 3 months of gel administration. The percentage increased slightly in the non-treated control group from 78.3% at baseline to 83% after 3 months. The percentage of patients who were tested positive for p16/Ki67 reduced from 75% at baseline to 5.3% in the treatment group after 6 months, while the percentage decreased only slightly in the non-treated group (baseline: 91.5%; 6 months: 75.2%). The examined vaginal gel may support the healing of conspicuous cytological findings (ASC-US, LSIL, ASC-H, or HSIL) and clearance of hr-human papillomavirus positive results.

Population-Based Incidence Rates of Cervical Intraepithelial Neoplasia in the Human Papillomavirus Vaccine Era

IMPORTANCE

A substantial effect of human papillomavirus (HPV) vaccines on reducing HPV-related cervical disease is essential before modifying clinical practice guidelines in partially vaccinated populations.

OBJECTIVE

To determine the population-based cervical intraepithelial neoplasia (CIN) trends when adjusting for changes in cervical screening practices that overlapped with HPV vaccination implementation.

DESIGN, SETTING, AND PARTICIPANTS

The New Mexico HPV Pap Registry, which captures population-based estimates of both cervical screening prevalence and CIN, was used to compute CIN trends from January 1, 2007, to December 31, 2014. Under New Mexico Administrative Code, the New Mexico HPV Pap Registry, a statewide public health surveillance program, receives mandatory reporting of all cervical screening (cytologic and HPV testing) and any cervical, vulvar, and vaginal histopathological findings for all women residing in New Mexico irrespective of outcome.

MAIN OUTCOME MEASURES

Prespecified outcome measures included low-grade CIN (grade 1 [CIN1]) and high-grade CIN (grade 2 [CIN2] and grade 3 [CIN3]).

RESULTS

From 2007 to 2014, a total of 13 520 CIN1, 4296 CIN2, and 2823 CIN3 lesions were diagnosed among female individuals 15 to 29 years old. After adjustment for changes in cervical screening across the period, reductions in the CIN incidence per 100 000 women screened were significant for all grades of CIN among female individuals 15 to 19 years old, dropping from 3468.3 to 1590.6 for CIN1 (annual percentage change [APC], -9.0; 95% CI, -12.0 to -5.8; P < .001), from 896.4 to 414.9 for CIN2 (APC, -10.5; 95% CI, -18.8 to -1.2; P = .03), and from 240.2 to 0 for CIN3 (APC, -41.3; 95% CI, -65.7 to 0.3; P = .05). Reductions in the CIN2 incidence were also significant for women 20 to 24 years old, dropping from 1027.7 to 627.1 (APC, -6.3; 95% CI, -10.9 to -1.4; P = .02).

CONCLUSIONS AND RELEVANCE

Population-level decreases in CIN among cohorts partially vaccinated for HPV may be considered when clinical practice guidelines for cervical cancer screening are reassessed. Evidence is rapidly growing to suggest that further increases in raising the age to start screening are imminent, one step toward integrating screening and vaccination.

Cervical cancer screening in women vaccinated against human papillomavirus infection: Recommendations from a consensus conference

In Italy, the cohorts of women who were offered Human papillomavirus (HPV) vaccination in 2007/08 will reach the age (25years) for cervical cancer (CC) screening from 2017. The simultaneous shift from cytology-based screening to HPV test-based screening gives the opportunity for unprecedented reorganisation of CC prevention. The ONS (National Screening Monitoring Centre) Directive and the GISCi (Italian Group for Cervical Screening) identified the consensus conference as the most suitable method for addressing this topic. A summary of consensus recommendations is reported here. The main objective was to define the best screening methods in girls vaccinated against HPV and the knowledge required for defining evidence-based screening strategies. A Jury made recommendations about questions and proposals formulated by a panel of experts representative of Italian scientific societies involved in CC prevention and based on systematic reviews of literature and evidence. The Jury considered changing the screening protocols for girls vaccinated in their twelfth year as appropriate. Tailored screening protocols based on vaccination status could be replaced by "one size fits all" protocols only when a herd immunity effect has been reached. Vaccinated women should start screening at age 30, instead of 25, with HPV test. Furthermore, there is a strong rationale for applying longer intervals for re-screening HPV negative women than the currently recommended 5years, but research is needed to determine the optimal screening time points. For non-vaccinated women and for women vaccinated in their fifteenth year or later, the current protocol should be kept.

Introduction of molecular HPV testing as the primary technology in cervical cancer screening: Acting on evidence to change the current paradigm

Since being introduced in the 1940s, cervical cytology - despite its limitations - has had unequivocal success in reducing cervical cancer burden in many countries. However, we now know that infection with human papillomavirus (HPV) is a necessary cause of cervical cancer and there is overwhelming evidence from large-scale clinical trials, feasibility studies and real-world experience that supports the introduction of molecular testing for HPV as the primary technology in cervical cancer screening (i.e., "HPV primary screening"). While questions remain about the most appropriate age groups for screening, screening interval and triage approach, these should not be considered barriers to implementation. Many countries are in various stages of adopting HPV primary screening, whereas others have not taken any major steps towards introduction of this approach. As a group of clinical experts and researchers in cervical cancer prevention from across Canada, we have jointly authored this comprehensive examination of the evidence to implement HPV primary screening. Our intention is to create a common understanding among policy makers, agencies, clinicians, researchers and other stakeholders about the evidence concerning HPV primary screening to catalyze the adoption of this improved approach to cervical cancer prevention. With the first cohort of vaccinated girls now turning 21, the age when routine screening typically begins, there is increased urgency to introduce HPV primary screening, whose performance may be less adversely affected compared with cervical cytology as a consequence of reduced lesion prevalence post-vaccination.

Review of Research on the Prevention of HPV Infection and Cervical Cancer

Worldwide, cervical cancer remains as one of the most common malignancies that threaten women's health. An epidemiological survey has shown that high-risk chronic HPV infection is the leading cause of cervical cancer. Thus, the prevention of HPV infection is the main approach to the prevention and treatment of cervical cancer. Sexual behavior, individual immunity, and age are important cofactors in the promotion of HPV infection. Preventive measures that have been gradually implemented worldwide have significantly decreased the incidence of cervical cancer in recent years. These measures include preventive vaccination against common high-risk HPV and cervical cancer screening, which includes HPV testing. HPV testing in cervical cancer screening has received increased attention and provides the basis for the prevention and treatment of cervical cancer. Given that HPV infection rates significantly vary from region to region, procedures for cervical cancer screening should be improved based on regional differences.

The significantly lower risk of cervical cancer at and after the recommended age to begin and end screening compared to breast and colorectal cancer

OBJECTIVE

We compare risk of cervical, colorectal, and breast cancer (and two pre-cancers: cervical intraepithelial neoplasia (CIN) grade 2-3 and colorectal adenomas) at and after the recommended ages to begin and end screening in the United States.

METHODS

Surveillance, Epidemiology, and End Results data were used with Monte Carlo simulations to estimate risk at and after the ages to screen.

RESULTS

At the age to begin screening, absolute risk of breast and colorectal cancer was 381 and 53 times higher, respectively, than cervical cancer (0.0122, 95% CI: 0.0089-0.0162 and 0.0017, 95% CI: 0.0012-0.0023 vs. 3.2e(-5), 95% CI: 2.3e(-5)-4.3e(-5)). Risk of colorectal adenomas and breast cancer was 45 and 2.4 times higher than CIN 2-3 (0.2319, 95% CI: 0.1287-0.3624 and 0.0122, 95% CI: 0.0089-0.0017 vs. 0.0051, 95% CI: 0.0029-0.0081). After the age to end screening, breast and colorectal cancer risk was 17 and 11 times higher, respectively, than cervical cancer.

CONCLUSIONS

Risk of cervical cancer at and after the recommended ages for screening is significantly lower than that of breast and colorectal cancer. Differences may become more pronounced in the era of HPV vaccines. Comparison of risk between cancers provides a novel perspective to inform future guideline development.

Human papillomavirus (HPV) types 16 and 18 in liquid-based cervical cytology samples

Human papillomavirus (HPV) DNA testing is replacing cervical cytology as a primary cervical cancer screening tool. The aim of this study was to determine the frequency of occurrence of HPV types 16 and 18 in liquid-based cytology (LBC) cervical samples in our set-up. This study comprised of 302 LBC cervical samples. HPV 16 and HPV 18 were detected by polymerase chain reaction (PCR), and the results were compared between normal (n = 155), inflammatory (n = 99), squamous (n = 37) and glandular abnormalities (n = 11). Of our patient cohort, 73.8 % was ≤40 years old. We found HPV 16 DNA in 91/302 (30.1 %) cases and HPV 18 DNA in 21/302 (6.95 %). HPV types 16 and 18 were detected in 25.8 and 4.5 % cytologically normal samples, respectively. HPV 16 was positive in 29.3 % of inflammatory samples. Squamous cervical abnormalities were more often HPV positive (HPV 16 in 48.6 %; HPV 18 in 29.7 %) than glandular abnormalities (36.4 and 18.2 %, respectively). We found high-risk HPV DNA in more than one third of the tested women. A good number of these HPV-positive cases were negative in cervical cytology.

Human papillomavirus vaccines: key factors in planning cost-effective vaccination programs

Prophylactic HPV vaccines hold tremendous potential for reducing cervical and non-cervical HPV-related disease burden worldwide. To maximize on this potential, policy officials will need to carefully consider available evidence, existing uncertainties and the cost-effectiveness of mass HPV vaccination programs in the context of their respective nations and/or regions. Proper harmonization of primary prevention strategies with secondary prevention efforts will also be important. Decisions following such considerations may ultimately depend on programmatic objectives, infrastructure and available resources. Continued research and surveillance surrounding HPV vaccination will be essential for filling current knowledge gaps, and forcing ongoing reconsiderations of selected immunization strategies.

The road ahead for cervical cancer prevention and control

Since the early 1950s, Papanicolaou ("Pap") cytology screening has dramatically reduced cervical cancer mortality in most high-income settings. Currently, human papillomavirus (hpv) vaccination has the greatest potential to reduce the global burden of cervical cancer and precancerous lesions. However, as the prevalence of precancerous lesions declines, maintaining cytology as the primary screening test in settings with established programs might become less efficient. A reduction in test performance (sensitivity, specificity, and positive predictive value) would lead to an increase in unnecessary colposcopy referrals. Fortunately, hpv dna testing has emerged as a suitable candidate to replace cytology. Compared with the Pap test, hpv testing is less specific but much more sensitive in detecting high-grade precancerous lesions, less prone to human error, and more reproducible across settings. Linkage of hpv vaccination and screening registries could serve the added role of monitoring vaccine efficacy. As a triage test, cytology is expected to perform with sufficient accuracy because most hpv-positive smears would contain relevant abnormalities. This approach and others-for example, hpv testing followed by genotyping-are being evaluated in large population studies and have already been recommended in some settings. Other specific biomarkers that might perform well for screening and triage include hpv E6/E7 messenger rna testing, methylation of host or viral genes, and p16(INK4a) staining. Considering the rapid pace of major discoveries and the anticipated arrival of a nonavalent hpv vaccine (currently in phase iii trials), the evidence base in this field has become an elusive target and will continue to be an obstacle for policymakers.

Trends in laboratory test volumes for Medicare Part B reimbursements, 2000-2010

CONTEXT

Changes in reimbursements for clinical laboratory testing may help us assess the effect of various variables, such as testing recommendations, market forces, changes in testing technology, and changes in clinical or laboratory practices, and provide information that can influence health care and public health policy decisions. To date, however, there has been no report, to our knowledge, of longitudinal trends in national laboratory test use.

OBJECTIVE

To evaluate Medicare Part B-reimbursed volumes of selected laboratory tests per 10,000 enrollees from 2000 through 2010.

DESIGN

Laboratory test reimbursement volumes per 10,000 enrollees in Medicare Part B were obtained from the Centers for Medicare & Medicaid Services (Baltimore, Maryland). The ratio of the most recent (2010) reimbursed test volume per 10,000 Medicare enrollees, divided by the oldest data (usually 2000) during this decade, called the volume ratio, was used to measure trends in test reimbursement. Laboratory tests with a reimbursement claim frequency of at least 10 per 10,000 Medicare enrollees in 2010 were selected, provided there was more than a 50% change in test reimbursement volume during the 2000-2010 decade. We combined the reimbursed test volumes for the few tests that were listed under more than one code in the Current Procedural Terminology (American Medical Association, Chicago, Illinois). A 2-sided Poisson regression, adjusted for potential overdispersion, was used to determine P values for the trend; trends were considered significant at P < .05.

RESULTS

Tests with the greatest decrease in reimbursement volumes were electrolytes, digoxin, carbamazepine, phenytoin, and lithium, with volume ratios ranging from 0.27 to 0.64 (P < .001). Tests with the greatest increase in reimbursement volumes were meprobamate, opiates, methadone, phencyclidine, amphetamines, cocaine, and vitamin D, with volume ratios ranging from 83 to 1510 (P < .001).

CONCLUSIONS

Although reimbursement volumes increased for most of the selected tests, other tests exhibited statistically significant downward trends in annual reimbursement volumes. The observed changes in reimbursement volumes may be explained by disease prevalence and severity, patterns of drug use, clinical or laboratory practices, and testing recommendations and guidelines, among others. These data may be useful to policy makers, health systems researchers, laboratory directors, and industry scientists to understand, address, and anticipate trends in laboratory testing in the Medicare population.

Reproducibility of linear array for human papillomavirus genotyping

We conducted a Linear Array test/retest analysis using cytologic specimens from 198 women. A total of 67.2% of samples had the same human papillomavirus (HPV) types detected in both tests (type-specific positive agreement was 83.3% overall [Kappa = 0.9] and 86.8% for carcinogenic types [Kappa = 0.92]). Discordance was highest with a low hybridization signal strength. Overall, Linear Array was highly reproducible.

Oncogenic HPV Types Infection in Adolescents and University Women from North Portugal: From Self-Sampling to Cancer Prevention

This study aimed to characterize the HPV infection status in adolescents and young university women in Portugal. The distribution of HPV genotypes was evaluated by PCR DNA genotyping after self-sampling collection from 435 women of exfoliated cervical cells using a commercial kit. We observed an overall frequency of HPV infection of 11.5%. Furthermore, HPV DNA prevalence was 16.6% in those young women that self-declared as sexually active. The more frequently detected HPV types were 31, 16, 53, and 61. Statistical analysis identified median age (OR = 3.56; P = 0.001), the number of lifetime sexual partners (OR = 4.50; P < 0.001), and years of sexual activity (OR = 2.36; P = 0.008) as risk factors for HPV acquisition. Hence, our study revealed that oncogenic HPV infection is common in young asymptomatic women Portuguese women, with a history of 2-5 sexual partners and over 2 year of sexual activity. Moreover, these results demonstrate that HPV detection performed in self-collected samples may be important to appraise better preventive strategies and to monitorize the influence of vaccination programmes within different populations.

Epidemiology and burden of HPV infection and related diseases: implications for prevention strategies

Human papillomavirus (HPV) infection is a necessary, although not sufficient cause of cervical cancer. Globally, HPV infection accounts for an estimated 530,000 cervical cancer cases (~270,000 deaths) annually, with the majority (86% of cases, 88% of deaths) occurring in developing countries. Approximately 90% of anal cancers and a smaller subset (<50%) of other cancers (oropharyngeal, penile, vaginal, vulvar) are also attributed to HPV. In total, HPV accounts for 5.2% of the worldwide cancer burden. HPVs 16 and 18 are responsible for 70% of cervical cancer cases and, especially HPV 16, for a large proportion of other cancers. Prophylactic vaccination targeting these genotypes is therefore expected to have a major impact on the burden of cervical cancer as well as that of other HPV-related cancers. Over the past 50 years, organized or opportunistic screening with Papanicolaou (Pap) cytology has led to major reductions in cervical cancer in most developed countries. However, due to lack of resources or inadequate infrastructure, many countries have failed to reduce cervical cancer mortality through screening. HPV DNA testing recently emerged as a likely candidate to replace Pap cytology for primary screening. It is less prone to human error and more sensitive than Pap in detecting high-grade cervical lesions. For countries with national vaccination programs, HPV testing may also serve as a low cost strategy to monitor long term vaccine efficacy. Introduction of well organized vaccination and screening programs should be a priority for all countries. Increased support from donors is needed to support this cause.

Adolescent and young adult HPV vaccination in Australia: achievements and challenges

Australia commenced an ongoing school based government funded human papillomaviruses (HPV) (cervical cancer prevention) vaccination program in April 2007 for adolescent females aged 12-13 years. In addition, up to December 31, 2009, a catch-up program for young females 13-26 years of age was offered: a school-based vaccination program was used to offer HPV vaccine to girls enrolled in school (14-17 years), and general practitioners or other community health provider offered vaccine to young women aged 18-26 years. To date, only the quadrivalent vaccine (HPV 6/11/16/18) has been utilized in the funded program. Acceptance of the vaccine is high with coverage of 3 doses of the HPV vaccine in the school age cohort around 70%, and just over 30% in the older age cohort. Since the vaccination program was initiated, a reduction in new cases of genital warts of 73% among vaccine eligible age females has been evidenced in STI clinics across Australia. A reduction of 44% of new cases in young males (not a part of the free program) was also documented during this same time period, suggesting significant herd immunity. Similarly, in the state of Victoria, a small but significant decrease in high grade abnormalities in Pap screening findings has been reported in young women<18 years for the period 2007-9, as compared to pre-vaccination. Challenges for the future include how we can sustain and improve HPV vaccination coverage in young Australian women, while maintaining cervical cancer screening participation and reviewing cervical cancer screening methods.

Measuring human papillomavirus (HPV) vaccination coverage and the role of the National HPV Vaccination Program Register, Australia

Accurate estimates of HPV vaccination coverage are critical for determining the proportion of the target female population that is not protected by the vaccine, as well as for monitoring the performance of vaccine delivery programs. The implementation of an HPV vaccination register, either as part of an existing immunisation register or stand-alone, can add substantial benefits to an HPV vaccination program. In Australia, the National HPV Vaccination Program Register supports the HPV vaccination program by providing information to consumers and providers about incomplete courses as well as estimates of vaccination coverage by age and area. Future monitoring of vaccine effectiveness will be facilitated by cross-linking to Pap test registries.

Early effect of the HPV vaccination programme on cervical abnormalities in Victoria, Australia: an ecological study

BACKGROUND

Australia introduced a human papillomavirus (HPV) vaccination programme with the quadrivalent HPV vaccine for all women aged 12-26 years between 2007 and 2009. We analysed trends in cervical abnormalities in women in Victoria, Australia, before and after introduction of the vaccination programme.

METHODS

With data from the Victorian Cervical Cytology Registry between 2003 and 2009, we compared the incidence of histopathologically defined high-grade cervical abnormalities (HGAs, lesions coded as cervical intraepithelial neoplasia of grade 2 or worse or adenocarcinoma in situ; primary outcome) and low-grade cytological abnormalities (LGAs) in five age groups before (Jan 1, 2003, to March 31, 2007) and after (April 1, 2007, to Dec 31, 2009) the vaccination programme began. Binary comparisons between the two periods were done with Fisher's exact test. Poisson piecewise regression analysis was used to compare incident rate trends.

FINDINGS

After the introduction of the vaccination programme, we recorded a decrease in the incidence of HGAs by 0·38% (95% CI 0·61-0·16) in girls younger than 18 years. This decrease was progressive and significantly different to the linear trend in incidence before introduction of the vaccination (incident rate ratio 1·14, 1·00-1·30, p=0·05). No similar temporal decline was recorded for LGAs or in older age groups.

INTERPRETATION

This is the first report of a decrease in incidence of HGAs within 3 years after the implementation of a population-wide HPV vaccination programme. Linkage between vaccination and screening registers is needed to confirm that this ecological observation is attributable to vaccination and to monitor participation in screening among vaccinated women.

FUNDING

None.

Feasibility of self-sampling and human papillomavirus testing for cervical cancer screening in First Nation women from Northwest Ontario, Canada: a pilot study

Background The incidence of cervical cancer is up to sixfold higher among First Nation women in Canada than in the general population. This is probably due to lower participation rates in cervical cancer prevention programmes. Objective To raise screening participation in this underserved population by launching an alternative approach to (Pap)anicolaou testing in a clinic-namely, vaginal self-sampling followed by human papillomavirus (HPV) diagnostics. Methods Good relationships were established with a First Nation community of the Northern Superior region in Northwest Ontario, and then 49 community women, aged 25-59, were recruited, who provided a vaginal self-sample and answered a questionnaire. Frequency distributions and cross-tabulations were used to summarise the data. Associations between categorical variables were assessed using the χ(2) test of association, or the Goodman-Kruskal γ if both variables had ordered categories. Self-collected samples were tested for integrity and HPV using optimised molecular biological methods. Results The majority of participants (87.2%) were amenable to future HPV screening by self-sampling. This finding was independent of age, educational level and a previous history of abnormal Pap tests. Interestingly, the preferred way to learn about sexual health remained through interaction with healthcare professionals. As defined by the presence of a housekeeping gene, self-sample integrity was high (96%). Using polymerase chain reaction-based Luminex typing, the overall HPV positivity was 28.6% (ie, with either a low- or high-risk type) and 16.3% were infected with a high-risk type such as HPV16. Conclusion In this pilot study of First Nation women, self-sampling and HPV testing was well received and self-sample quality was excellent. A larger survey to be conducted in other Northern Superior communities in Northwest Ontario will determine whether this approach could become a viable screening strategy for First Nation women.

Cumulative Epigenetic Abnormalities in Host Genes with Viral and Microbial Infection during Initiation and Progression of Malignant Lymphoma/Leukemia

Although cancers have been thought to be predominantly driven by acquired genetic changes, it is becoming clear that microenvironment-mediated epigenetic alterations play important roles. Aberrant promoter hypermethylation is a prevalent phenomenon in human cancers as well as malignant lymphoma/leukemia. Tumor suppressor genes become frequent targets of aberrant hypermethylation in the course of gene-silencing due to the increased and deregulated DNA methyltransferases (DNMTs). The purpose of this article is to review the current status of knowledge about the contribution of cumulative epigenetic abnormalities of the host genes after microbial and virus infection to the crisis and progression of malignant lymphoma/leukemia. In addition, the relevance of this knowledge to malignant lymphoma/leukemia assessment, prevention and early detection will be discussed.