Modeling of US Human Papillomavirus (HPV) Seroprevalence by Age and Sexual Behavior Indicates an Increasing Trend of HPV Infection Following the Sexual Revolution

Understanding the high-risk human papillomavirus prevalence and associated factors in the European country with a high incidence of cervical cancer

BACKGROUND

High-risk human papillomavirus (HR-HPV) is a known cause of cervical cancer (CC). Latvia has a high incidence of CC compared with the average incidence in the European Union. This study aims to fill the data gap on the HR-HPV burden in Latvia, providing information on its prevalence and associated factors.

METHODS

The cross-sectional study was conducted from February 2021 to April 2022. Participants 25-70 years old visiting a general practitioner (general population) or those referred to a colposcopy clinic with changes in their cervical cytology (colposcopy population) collected vaginal self-sample and completed a paper-based questionnaire. Samples were analyzed with Cobas 6800 System (Roche) for HPV16, HPV18 and other HR-HPV (HPV31/33/35/39/45/51/52/56/58/59/66/68). Descriptive statistics for categorical variables were performed. The Chi-square test was used to determine for the statistical significance of differences in the proportions of the dependent variable between subgroups of the independent variable. Univariate and multivariate binary logistic regression were used to identify factors associated with positive HR-HPV status. Results were considered statistically significant at P < 0.05.

RESULTS

A total of 1274 participants provided a valid sample. The prevalence of any HR-HPV infection was 66.8% in the colposcopy group and 11.0% in the general population. Factors associated with positive HR-HPV status were marital status single/divorced/widowed (vs. married/cohabiting) [adjusted OR (aOR) 2.6; P = 0.003], higher number of lifetime sex partners [aOR 5.1 (P < 0.001) and 4.0 (P = 0.001)] for six or more and three to five partners in the general population; in the colposcopy group, the statistical significance remained only for Latvian ethnicity (vs. other) (aOR 1.8; P = 0.008) and current smoking (vs. never) (aOR 1.9; P = 0.01).

CONCLUSION

We documented a comparison to European Union HR-HPV infection burden in Latvia. Any HR-HPV positivity was significantly associated with sexual and other health behavior.

Epidemiology of HPV-associated cancers past, present and future: towards prevention and elimination

Cervical cancer is the first cancer deemed amenable to elimination through prevention, and thus lessons from the epidemiology and prevention of this cancer type can provide information on strategies to manage other cancers. Infection with the human papillomavirus (HPV) causes virtually all cervical cancers, and an important proportion of oropharyngeal, anal and genital cancers. Whereas 20th century prevention efforts were dominated by cytology-based screening, the present and future of HPV-associated cancer prevention relies mostly on HPV vaccination and molecular screening tests. In this Review, we provide an overview of the epidemiology of HPV-associated cancers, their disease burden, how past and contemporary preventive interventions have shaped their incidence and mortality, and the potential for elimination. We particularly focus on the cofactors that could have the greatest effect on prevention efforts, such as parity and human immunodeficiency virus infection, as well as on social determinants of health. Given that the incidence of and mortality from HPV-associated cancers remain strongly associated with the socioeconomic status of individuals and the human development index of countries, elimination efforts are unlikely to succeed unless prevention efforts focus on health equity, with a commitment to both primary and secondary prevention.

Papillomaviruses and cancer: commonalities and differences in HPV carcinogenesis at different sites of the body

Human papillomavirus (HPV) is associated with 5% of all cancers globally at a range of body sites, including cervix, anus, penis, vagina, vulva, and oropharynx. These cancers claim > 400,000 lives annually. The persistent infection of HPV and the function of viral oncogenes are the primary causes of HPV-related cancers. However, only some HPV-infected persons or infected lesions will progress to cancer, and the burden of HPV-associated cancer varies widely according to gender and the part of the body infected. The dissimilarity in infection rates at different sites can explain only a small part of the differences observed. Much responsibility likely sits with contributions of specific epithelial cells and the cellular microenvironment at infected sites to the process of malignant transformation, both of which affect the regulation of viral gene expression and the viral life cycle. By understanding the biology of these epithelial sites, better diagnosis/treatment/management of HPV-associated cancer and/or pre-cancer lesions will be provided.

Prevalence of cervical human papillomavirus in Mexico, 2010-2017: analysis of 2.7 million women

PURPOSE

Prevalence of cervical high-risk human papillomavirus (hrHPV) infection varies greatly. Data on distribution of hrHPV infection constitute important evidence for decision-making when implementing HPV testing into cervical cancer screening programs. We estimate the prevalence of cervical hrHPV infection in a large sample of women in a middle-income country and explore variation by age, community marginalization and region in women using public cervical cancer screening services.

METHODS

Records covering 2010-2017 from a registry of hrHPV test results (Hybrid Capture 2 and polymerase chain reaction) in 2,737,022 women 35-64 years were analyzed. In this observational study, 32 states were categorized into five geographical regions and classified by degree of marginalization. We stratified by test type and estimated crude and adjusted prevalence and rate ratios and used Poisson models and joinpoint regression analysis.

RESULTS

Prevalence was higher in women 35-39 years, at 10.4% (95% CI 10.3-10.5) and women 60-64 years, at 10.1% (95% CI 10.0-10.3). Prevalence was higher in the southeast, at 10.5% (95% CI 10.4-10.6). Women living in less marginalized areas had a significantly higher prevalence, at 10.3% (95% CI 10.2-10.4) compared to those in highly marginalized areas, at 8.7% (95% CI 8.5-8.7). HPV16 infection was detected in 0.92% (2,293/23,854) of women and HPV18 infection was detected in 0.39% (978/23,854) of women.

CONCLUSION

Understanding the distribution of HPV prevalence has value as evidence for developing policy in order to improve cervical cancer screening strategies. These results will constitute evidence to allow decision makers to better choose where to focus those resources that they do have.

Impact of human papillomavirus vaccine on cervical cancer epidemic: Evidence from the surveillance, epidemiology, and end results program

Introduction

Since 2006, the human papillomavirus (HPV) vaccine has been recommended for females aged 9-26 years in the United States. Aiming to evaluate the early effect of the HPV vaccine on cervical cancer, this study assessed the incidence of cervical cancer by age and histology before and after the introduction of HPV vaccination.

Methods

Data on cervical cancer incidence from 1975-2019 were extracted from the Surveillance, Epidemiology, and End Results Program. Joinpoint regression was used to determine temporal trends over time. Future cervical cancer incidence (2015-2039) was projected using Bayesian age-period-cohort analysis. Age-period-cohort (APC) models were created to evaluate age, period, and cohort effects.

Results

For overall cervical cancer and cervical squamous cell carcinoma (SCC), incidence rate showed decreasing trends (-0.7%, and -1.0% annually, respectively), whereas cervical adenocarcinoma (AC) incidence continuously increased (2.6% annually). The incidence trends for AC were stable in the 20-24 and 25-29-year age groups, whereas there was an increasing trend in older age groups. Similarly, the projected trend for AC in females aged 20-30 years exhibited a decline, whereas an increase was predicted in the 31-40-year age group, especially in the 35-44 year age group. The birth cohort and period effects in SCC and AC were extracted from APC models.

Discussion

During the period of 1975-2019, the incidence of cervical AC remained almost unchanged in the age groups receiving HPV vaccines while increased in the age groups not receiving HPV vaccines. The birth cohort effects of SCC and AC of the cervix provided evidence supporting the effectiveness of the HPV vaccine in preventing cervical cancer.

Risk Assessment of Human Papillomavirus-Positive Cytology-Negative Cervical Cancer Screening in Black and White Women

OBJECTIVES

As we move toward human papillomavirus (HPV) only as the preferred cervical cancer screening method, we performed a retrospective analysis of Black and White women with negative cytology (Papanicolaou negative [PAPneg]) and positive high-risk HPV (hrHPV) (HPVpos) results and determined follow-up.

METHODS

We searched our pathology data system for patients with PAPneg/HPVpos results (2017-2019). Follow-up data were reviewed (39 months), and a comparison among race was performed.

RESULTS

In total, 1,728 patients were identified (Black, 53%; White, 47%). Twenty-nine percent of the patients had no follow-up with no difference among the races. HPV 16 was more common among Whites (P < .01), while non-16/18 hrHPV was more common among Black patients (P = .01). A total of 30 (3.3%) Black and 26 (3.2%) White patients were diagnosed with cervical intraepithelial neoplasia grade 2/3 (CIN 2/3). More White women were diagnosed on biopsy alone (negative endocervical curettage) compared with Black women (20 vs 9, P < .01). Meanwhile, there were 21 Black and 6 White women with CIN 2/3 on endocervical curettage (P = .01).

CONCLUSIONS

Follow-up of women with PAPneg/HPVpos remains a challenge. There was no disparity in follow-up when cohorts were compared. However, Black women had higher numbers of high-grade intraepithelial lesions on endocervical curettage.

The Vaginal Microbiome: IV. The Role of Vaginal Microbiome in Reproduction and in Gynecologic Cancers

OBJECTIVE

This series of articles, titled The Vaginal Microbiome (VMB), written on behalf of the International Society for the Study of Vulvovaginal Disease, aims to summarize the recent findings and understanding of the vaginal bacterial microbiota, mainly regarding areas relevant to clinicians specializing in vulvovaginal disorders.

MATERIALS AND METHODS

A search of PubMed database was performed, using the search terms "vaginal microbiome" with "reproduction," "infertility," "fertility," "miscarriages," "pregnancy" "cervical cancer," "endometrial cancer," and "ovarian cancer." Full article texts were reviewed. Reference lists were screened for additional articles.

RESULTS

The fourth article of this series focuses on 2 distinct areas: the role of VMB in various aspects of human reproduction and, in sharp contrast, the association between the VMB and gynecologic malignancies. Several of the negative pregnancy outcomes have been associated with an altered VMB. Dysbiosis is remarkably linked with poor pregnancy outcomes from preconception to delivery. The associations between the microbiome and gynecologic cancers are described.

CONCLUSIONS

The development of the microbiome research, enabled by molecular-based techniques, has dramatically increased the detection of microorganisms and the understanding of bacterial communities that are relevant to maternal-fetal medicine in health and disease, as well as in gynecological malignancies. Proving causation in cancer is difficult because of the complex interactive nature of potential causative factors. Certain elements of the microbiota have been shown to provoke inflammatory reactions, whereas others produce anti-inflammatory reactions; this balance might be impaired with a change in microbial variety.

Estimating HIV, HCV and HSV2 incidence from emergency department serosurvey

Background: Our understanding of pathogens and disease transmission has improved dramatically over the past 100 years, but coinfection, how different pathogens interact with each other, remains a challenge. Cross-sectional serological studies including multiple pathogens offer a crucial insight into this problem.  Methods: We use data from three cross-sectional serological surveys (in 2003, 2007 and 2013) in a Baltimore emergency department to predict the prevalence for HIV, hepatitis C virus (HCV) and herpes simplex virus, type 2 (HSV2), in a fourth survey (in 2016). We develop a mathematical model to make this prediction and to estimate the incidence of infection and coinfection in each age and ethnic group in each year. Results: Overall we find a much stronger age cohort effect than a time effect, so that, while incidence at a given age may decrease over time, individuals born at similar times experience a more constant force of infection over time. Conclusions: These results emphasise the importance of age-cohort counselling and early intervention while people are young. Our approach adds value to data such as these by providing age- and time-specific incidence estimates which could not be obtained any other way, and allows forecasting to enable future public health planning.

Human papillomavirus prevalence and risk factors among Australian women 9-12 years after vaccine program introduction

BACKGROUND

In Australia, high and widespread uptake of the quadrivalent human papillomavirus (HPV) vaccine has led to substantial population-level reductions in the prevalence of quadrivalent vaccine targeted HPV genotypes 6/11/16/18 in women aged ≤ 35 years. We assessed risk factors for HPV detection among 18-35 year old women, 9-12 years after vaccine program introduction.

METHODS

Women attending health services between 2015 and 2018 provided a self-collected vaginal specimen for HPV genotyping (Roche Linear Array) and completed a questionnaire. HPV vaccination status was validated against the National Register. Adjusted odds ratios (aORs) and 95% confidence intervals (CI) were calculated for factors associated with HPV detection.

RESULTS

Among 1564 women (median age 24 years; IQR 21-27 years), Register-confirmed ≥ 1-dose vaccine coverage was highest at 69.3% and 68.1% among women aged 18-21 and 22-24 years respectively, decreasing to 42.9% among those aged 30-35 years. Overall prevalence of quadrivalent vaccine-targeted HPV types was very low (2.0%; 95% CI: 1.4-2.8%) and influenced only by vaccination status (5.5% among unvaccinated compared with 0.7% among vaccinated women; aOR = 0.13 (95% CI: 0.05-0.30)). Prevalence of remaining HPV types, at 40.4% (95% CI: 38.0-42.9%), was influenced by established risk factors for HPV infection; younger age-group (p-trend < 0.001), more recent (p < 0.001) and lifetime sexual partners (p-trend < 0.001), but not vaccination status. Prevalence of HPV31/33/45, which shared risk factors with that of non-vaccine targeted HPV types, was also lower among vaccinated (4%) compared with unvaccinated (7%) women (aOR = 0.51; 95% CI: 0.29-0.89), indicative of cross-protection.

CONCLUSION

Vaccination has changed the epidemiology of HPV infection in Australian women, having markedly reduced the prevalence of vaccine-targeted types, including amongst women with known risk factors for infection. Vaccinated women appear to be benefiting from modest cross-protection against types 31/33/45 afforded by the quadrivalent HPV vaccine. These results reinforce the importance of HPV vaccination.

Public health impact and cost-effectiveness of catch-up 9-valent HPV vaccination of individuals through age 45 years in the United States

The Advisory Committee on Immunization Practices (ACIP) recommended catch-up 9-valent Human Papillomavirus (HPV) vaccination through age 26 years, and shared clinical decision-making for adults aged 27-45 years, compared with catch-up through age 26 years and 21 years for females and males, respectively (status quo; pre-June-2019 recommendations). This study assessed the public health impact and cost-effectiveness of expanded catch-up vaccination through age 45 years (expanded catch-up) compared with status quo. We used an HPV dynamic transmission infection and disease model to assess disease outcomes and incremental cost-effectiveness ratio (ICER) of expanded catch-up compared with status quo. Costs (2018 USD), calculated from a healthcare sector perspective, and quality-adjusted life years (QALY) were discounted at 3% annually. Historical vaccination coverage was estimated using NIS-TEEN survey data (NHANES data for sensitivity analysis). Alternative scenario analyses included restricting upper age of expanded catch-up through 26 years (June-2019 ACIP recommendation), 29 years, and further 5-year increments. Our results show expanded catch-up vaccination would prevent additional 37,856 cancers, 314,468 cervical intraepithelial neoplasia-2/3s, 1,743,461 genital warts, and 10,698 deaths compared with status quo over 100 years at cost of $141,000/QALY. With NHANES coverage, the ICER was $96,000/QALY. The June-2019 ACIP recommendation also provided public health benefits with an ICER of $117,000/QALY, compared with status quo. The ICER for expanded vaccination through age 34 years was $107,000/QALY. Expanding catch-up vaccination program through age 45 years-old in the US is expected to provide public health benefits, and cost-effectiveness improves with expanding catch-up through age 34.

Importance of Lifetime Sexual History on the Prevalence of Genital Human Papillomavirus (HPV) Among Unvaccinated Adults in the National Health and Nutrition Examination Surveys: Implications for Adult HPV Vaccination

BACKGROUND

Although the United States Food and Drug Administration recently approved the human papillomavirus (HPV) vaccine for individuals aged 27-45 years, the Centers for Disease Control and Prevention did not change its guidelines for routine HPV vaccination. Since recommendations for adult vaccination emphasize shared clinical decision-making based on risk of new infections, we examined the relationship between HPV prevalence and sexual behavior.

METHODS

This study was conducted among 5093 HPV-unvaccinated, sexually experienced adults aged 18-59 years in the National Health and Nutrition Examination Surveys (2013-2016). For each sex and age group, adjusted prevalences of 9-valent vaccine-specific, high-risk, and any HPV infection were estimated by number of lifetime sexual partners (LTSPs) using logistic regression. An analysis restricted to persons who did not have a new sexual partner in the past year (ie, removing those at highest risk of newly acquired HPV) was also conducted.

RESULTS

In each age group, genital HPV prevalence was higher among persons with >5 LTSPs compared with 1-5 LTSPs in both males and females. There were only slight reductions in HPV prevalence after removing participants who reported a new sexual partner in the past year. For example, among females aged 27-45 years with >5 LTSPs, the adjusted prevalence of 9-valent vaccine-type HPV infection was 13.4% (95% confidence interval [CI], 9.9%-17.0%) in the full population compared to 12.1% (95% CI, 8.8%-15.4%) among those with no new sexual partners.

CONCLUSIONS

Prevalent HPV infection was primarily reflective of cumulative exposures over time (higher LTSPs). New exposures had limited impact, emphasizing the need to consider sexual history in the decision-making process for adult HPV vaccination.

Oncologic Outcomes Following Transoral Robotic Surgery for Human Papillomavirus-Associated Oropharyngeal Carcinoma in Older Patients

Importance

While early epidemiologic studies ascribed increases in the incidence of human papillomavirus-associated oropharyngeal cancers to middle-aged patients, recent analyses have demonstrated an increasing median age of diagnosis. Treatment of patients older than 70 years is controversial as their inclusion in the practice-defining clinical trials has been limited and the survival benefit conferred by chemotherapy may be outweighed by treatment toxic effects.

Objective

To assess the oncologic outcomes of older adults with human papillomavirus-associated oropharyngeal cancer who underwent upfront transoral robotic surgery and pathologic characteristics-guided adjuvant therapy in a large cohort of patients with close follow-up.

Design, Setting, and Participants

A retrospective cohort analysis was conducted in a tertiary care academic medical center between January 1, 2010, and December 30, 2017. Patients aged 70 years or older at time of diagnosis with biopsy-proven and surgically resectable p16-positive oropharyngeal cancers were included. Data analysis was conducted from March 1 to June 1, 2020.

Exposures

Transoral robotic surgery oropharyngeal resection and neck dissection with pathologic characteristic-guided adjuvant therapy.

Main Outcomes and Measures

Three-year estimates of disease-specific survival, overall survival, and disease-free survival, as well as rates of adjuvant therapy (radiotherapy and chemoradiotherapy) and perioperative complications.

Results

Seventy-seven patients were included (median age, 73.0; interquartile range, 71.0-76.0; range, 70-89 years); of these, 58 were men (75.3%). Perioperative mortality was 1.3% and the rate of oropharyngeal hemorrhage was 2.6%. Twenty-seven patients (35.1%) underwent postoperative radiotherapy and 20 patients (26.0%) underwent postoperative chemoradiotherapy. The median length of follow-up was 39.6 (range, 0.1-96.2) months, and the 3-year estimates of survival were 92.4% (95% CI, 82.4%-96.9%) for disease-specific survival, 90.0% (95% CI, 79.4%-95.0%) for overall survival, and 84.3% (95% CI, 73.4%-91.0%) for disease-free survival.

Conclusions and Relevance

The findings of this cohort study suggest that transoral robotic surgery and pathologic characteristic-guided adjuvant therapy can provide beneficial survival outcomes, infrequent perioperative mortality, and, for most carefully selected older adults, obviate the need for chemotherapy.

Rates of New Human Papillomavirus Detection and Loss of Detection in Middle-aged Women by Recent and Past Sexual Behavior

BACKGROUND

Understanding the source of newly detected human papillomavirus (HPV) in middle-aged women is important to inform preventive strategies, such as screening and HPV vaccination.

METHODS

We conducted a prospective cohort study in Baltimore, Maryland. Women aged 35-60 years underwent HPV testing and completed health and sexual behavior questionnaires every 6 months over a 2-year period. New detection/loss of detection rates were calculated and adjusted hazard ratios were used to identify risk factors for new detection.

RESULTS

The new and loss of detection analyses included 731 women, and 104 positive for high-risk HPV. The rate of new high-risk HPV detection was 5.0 per 1000 woman-months. Reporting a new sex partner was associated with higher detection rates (adjusted hazard ratio, 8.1; 95% confidence interval, 3.5-18.6), but accounted only for 19.4% of all new detections. Among monogamous and sexually abstinent women, new detection was higher in women reporting ≥5 lifetime sexual partners than in those reporting <5 (adjusted hazard ratio, 2.2; 95% confidence interval, 1.2-4.2).

CONCLUSION

Although women remain at risk of HPV acquisition from new sex partners as they age, our results suggest that most new detections in middle-aged women reflect recurrence of previously acquired HPV.

Co-infection between genotypes of the human papillomavirus and Chlamydia trachomatis in Mexican women

Not all human papillomavirus (HPV) infections develop into cervical cancer (CC), so it is proposed that other factors may influence this, such as co-infection with Chlamydia trachomatis (CT). To identify the prevalence of co-infection, we included 189 women with suspicion of HPV. Viral typing was performed by carrying out the Roche HP Linear Array test, while CT detection was performed with the COBAS® TaqMan® 48 kit from Roche. Of the 189 women only 184 had an infection with HPV, CT or both: 56.6% were positive for one or several HPV genotypes, and 67.7% for CT. Clinical data showed an association between HPV and CIN I (n = 22; RR = 2.43; 95% CI 1.72-3.43, p < 0.05). CT infection was only associated with cervicitis (n = 40; RR = 1.73; 95% CI 1.34-2.23, p < 0.05). The CT-HPV co-infection rate was 28%. Co-infection revealed an association with CIN I (n = 31, RR= 3.33; 95% CI 2.08-5.34 p < 0.05), CIN III (n = 7; RR = 2.57; 95% CI 1.53-4.31, p < 0.05); and a significant risk of 2.3 (95% CI 1.08-4.90) times higher to develop CC; nevertheless, this risk was not statistically significant. CT/HPV co-infection was associated with the development of a high-grade lesion (CIN III) as well as an important risk for developing CC.

Evolving Profile of HPV-Driven Oropharyngeal Squamous Cell Carcinoma in a National Cancer Institute in Italy: A 10-Year Retrospective Study

Globally, 30% of oropharyngeal carcinomas (OPSCC) are caused by Human Papillomavirus (HPV). Recently, increasing incidence trends for HPV-driven OPSCC have been reported in many countries and changes in the typical HPV-positive OPSCC patient have been recorded, with an increase in the median age and diagnoses in women. We investigated the characteristics of the OPSCC patients attending an Italian Cancer Institute from 2010 to 2019 and assessed possible changes overtime of demographic, behavioral, and clinico-pathologic variables of HPV-driven OPSCC. Overall, 339 OPSCCs were evaluated. HPV-DNA and p16 positivity were 48.7% and 55.2%, respectively, with an HPV-driven fraction (i.e., HPV-DNA+/p16+) of 48.3%. We observed a significant increase overtime in the rate of HPV-associated cases (53.7% in 2015–2019 vs. 40.3% in 2010–2014, p = 0.019). The rate of HPV-driven cases was significantly higher among women, never smokers, patients with T1–T2 tumors, and with nodal involvement. A trend was also observed toward an increase in HPV-driven OPSCCs among patients >61 years, women, former smokers, and patients with no nodal involvement in 2015–2019. Our findings consolidate the observation that HPV-associated OPSCCs are also increasing in Italy. Moreover, they suggest that the profile of the HPV-driven OPSCC patient might be changing.

The microbiome and gynaecological cancer development, prevention and therapy

The female reproductive tract (FRT), similar to other mucosal sites, harbours a site-specific microbiome, which has an essential role in maintaining health and homeostasis. In the majority of women of reproductive age, the microbiota of the lower FRT (vagina and cervix) microenvironment is dominated by Lactobacillus species, which benefit the host through symbiotic relationships. By contrast, the upper FRT (uterus, Fallopian tubes and ovaries) might be sterile in healthy individuals or contain a low-biomass microbiome with a diverse mixture of microorganisms. When dysbiosis occurs, altered immune and metabolic signalling can affect hallmarks of cancer, including chronic inflammation, epithelial barrier breach, changes in cellular proliferation and apoptosis, genome instability, angiogenesis and metabolic dysregulation. These pathophysiological changes might lead to gynaecological cancer. Emerging evidence shows that genital dysbiosis and/or specific bacteria might have an active role in the development and/or progression and metastasis of gynaecological malignancies, such as cervical, endometrial and ovarian cancers, through direct and indirect mechanisms, including modulation of oestrogen metabolism. Cancer therapies might also alter microbiota at sites throughout the body. Reciprocally, microbiota composition can influence the efficacy and toxic effects of cancer therapies, as well as quality of life following cancer treatment. Modulation of the microbiome via probiotics or microbiota transplant might prove useful in improving responsiveness to cancer treatment and quality of life. Elucidating these complex host-microbiome interactions, including the crosstalk between distal and local sites, will translate into interventions for prevention, therapeutic efficacy and toxic effects to enhance health outcomes for women with gynaecological cancers.

Integrating measures of viral prevalence and seroprevalence: a mechanistic modelling approach to explaining cohort patterns of human papillomavirus in women in the USA

Incidence of human papillomavirus (HPV) related cancers is increasing, generating substantial interest in understanding how trends in population prevalence of HPV infection are changing. However, there are no direct, population-scale measurements of HPV prevalence prior to 2003. Previous work using models to reconstruct historical trends have focused only on genital infection or seroprevalence (prevalence of antibodies) separately, and the results of these single-measure studies have been hard to reconcile. Here, we develop a mechanistic disease model fit jointly to cervicogential prevalence and seroprevalence in unvaccinated women in the USA using National Health and Nutrition Examination Survey data (2003-2010) and compare it to fits of statistical age-cohort models. We find that including a latent HPV state in our model significantly improves model fit and that antibody waning may be an important contributor to observed patterns of seroprevalence. Moreover, we find that the mechanistic model outperforms the statistical model and that the joint analysis prevents the inconsistencies that arise when estimating historical cohort trends in infection from genital prevalence and seroprevalence separately. Our analysis suggests that while there is substantial uncertainty associated with the estimation of historic HPV trends, there has likely been an increase in the force of infection for more recent birth cohorts. This article is part of the theme issue 'Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses'.

Sexual behavior and infection with cervical human papillomavirus types 16 and 18

Objective

This study assessed whether sexual behavior, including engaging in early sexual intercourse and having had multiple sexual partners, can predict the risk of infection with cervical human papillomavirus (HPV) types 16 and 18.

Methods

Records were reviewed of women who underwent cervical cancer screening and were found to be infected with high-risk HPV. The genotypes of high-risk HPV were categorized as HPV 16, HPV 18, and other than 16 or 18. Early sexual intercourse was defined as first sexual intercourse at the age of 19 years or younger. Multiple sexual partners was defined as having more than three lifetime sexual partners. Associations between sexual behavior and HPV 16/18 infection were presented as odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Of the 349 women included in the study, 72 (20.6%) and 30 (8.6%) were infected by HPV 16 and 18, respectively. Eighty-two women (26.0%) reported having engaged in early sexual intercourse, and 33 (10.4%) reported having had multiple sexual partners. After adjustment for age, parity, and smoking habits, we found that women who had engaged in early sexual intercourse tended to have a higher risk of HPV 16 (OR 1.74; 95% CI 0.93-3.29), and those who had had multiple sexual partners were found to be at a significantly higher risk for HPV 18 (OR 4.58; 95% CI 1.44-14.58).

Conclusion

Sexual behavior was associated with an increased risk of HPV 16/18 infection. Engaging in early sexual intercourse increased the risk of HPV 16 infection, and having had multiple sexual partners increased that of HPV 18.

Case Studies of Gastric, Lung, and Oral Cancer Connect Etiologic Agent Prevalence to Cancer Incidence

Obtaining detailed individual-level data on both exposure and cancer outcomes is challenging, and it is difficult to understand and characterize how temporal aspects of exposures translate into cancer risk. We show that, in lieu of individual-level information, population-level data on cancer incidence and etiologic agent prevalence can be leveraged to investigate cancer mechanisms and to better characterize and predict cancer trends. We use mechanistic carcinogenesis models [multistage clonal expansion (MSCE) models] and data on smoking, Helicobacter pylori (H. pylori), and HPV infection prevalence to investigate trends of lung, gastric, and HPV-related oropharyngeal cancers. MSCE models are based on the initiation-promotion-malignant conversion paradigm and allow for interpretation of trends in terms of general biological mechanisms. We assumed the rates of initiation depend on the prevalence of the corresponding risk factors. We performed two types of analysis, using the agent prevalence and cancer incidence data to estimate the model parameters and using cancer incidence data to infer the etiologic agent prevalence as well as the model parameters. By including risk factor prevalence, MSCE models with as few as three parameters closely reproduced 40 years of age-specific cancer incidence data. We recovered trends of H. pylori prevalence in the United States and demonstrated that cohort effects can explain the observed bimodal, age-specific pattern of oral HPV prevalence in men. Our results demonstrate the potential for joint analyses of population-level cancer and risk factor data through mechanistic modeling. This approach can be a first step in systematically testing relationships between exposures and cancer risk when individual-level data is lacking.Significance: Analysis of trends in risk-factor prevalence and cancer incidence can shed light on cancer mechanisms and the way that carcinogen exposure through time shapes the risk of cancer at different ages.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/12/3386/F1.large.jpg Cancer Res; 78(12); 3386-96. ©2018 AACR.

Trends in cervical cancer incidence rates by age, race/ethnicity, histological subtype, and stage at diagnosis in the United States

Recent trends of cervical cancer incidence by histology and age in the United States (U.S.) have not been reported. We examined contemporary trends in cervical squamous cell carcinoma (SCC) and adenocarcinoma (AC) incidence rates in the U.S. by age group, race/ethnicity, and stage at diagnosis after accounting for hysterectomy. Incidence data (1999-2015) were obtained from the U.S. Cancer Statistics Incidence Analytic Database. Hysterectomy prevalence was estimated using National Health Interview Survey data (2000-2015). Overall SCC incidence rates continued to decrease in all racial/ethnic groups except among non-Hispanic whites in whom rates stabilized in the 2010s, largely driven by stable trends in ages <50 years and a slower pace of decrease in ages 50-59 years. After a stable trend between 1999 and 2002, AC incidence rates among non-Hispanic whites rose during 2002-2015 (1.3% per year), mostly due to increases in ages 40-49 (4.4% annually since 2004) and 50-59 years (5.5% annually since 2011). Overall AC incidence rates during 1999-2015 decreased in blacks and Hispanics but were stable in Asian/Pacific Islanders; in all these race/ethnicities, rates were generally stable in ages <50 years but decreasing in older ages. Rates of distant stage cervical SCC and AC among non-Hispanic whites increased in several age groups but were generally stable in non-whites. Increasing or stabilized incidence trends for AC and attenuation of earlier declines for SCC in several subpopulations underscore the importance of intensifying efforts to reverse the increasing trends and further reduce the burden of cervical cancer in the U.S.

Multisite HPV infections in the United States (NHANES 2003-2014): An overview and synthesis

HPV is the most common sexually transmitted infection in the U.S., infecting both anogenital and oral sites. Nationally representative data are collected through the National Health and Nutrition Examination Survey (NHANES). However, changing designations of HPV genotypes as high or low risk and varying underlying populations as new results are reported have made direct comparison of results difficult. We reanalyzed HPV data from NHANES derived from self-collected cervicovaginal swabs (women ages 18-59, 2003-14), penile swabs (men ages 18-59, 2013-14), and oral rinses (men and women ages 18-69, 2009-14), using consistent populations and definitions across NHANES cycles. These data strengthen our understanding of age trends in HPV prevalence: cervicovaginal prevalence decreases with age, penile prevalence increases with age, and oral prevalence is bimodal but with an earlier first peak in women. There is strong evidence for reduced prevalence of vaccine genotypes (6, 11, 16, 18) in vaccinated men and women (ages 18-24) at both genital (RR 0.2 (0.1-0.3) in women and 0.7 (0.1-5.4) in men) and oral sites (RR 0.1 (0.0-1.3) in women; no infections detected in vaccinated men). A more complete picture of the burden of HPV in the U.S. is emerging, including evidence for reduced HPV genital and oral prevalence in vaccinated individuals.

Might Oral Human Papillomavirus (HPV) Infection in Healthy Individuals Explain Differences in HPV-Attributable Fractions in Oropharyngeal Cancer? A Systematic Review and Meta-analysis

BACKGROUND

Differences in oral human papillomavirus (HPV) prevalence and contrasts in HPV-attributable fractions (AFs) in oropharyngeal cancer (OPC) have not been evaluated in depth.

METHODS

A systematic review was performed to identify studies in which at least 50 healthy individuals were tested for oral HPV infection. Information on sex, age, tobacco/alcohol consumption, sex practices, specimen collection, HPV detection, and population type was extracted. Prevalences were pooled using random-effects models for meta-analyses of binomial data. Correlations were assessed by the Spearman test.

RESULTS

Forty-eight reports comprising 28 544 individuals fulfilled inclusion criteria. Global oral HPV prevalence was 4.9%. Estimates were highest in Europe, although regional differences were not statistically significant. HPV16 prevalence was 1.0% globally, and regional differences became statistically significant. A lifetime history of >6 sex partners showed a higher risk of oral HPV infection. The age-specific HPV distribution revealed a prevalence of ≥5% over 40 years of age and a lower prevalence at younger ages. There was no association between oral HPV prevalence and HPV-AFs or age-standardized rates (ASRs) of OPC, genital HPV in healthy women, or tobacco use.

CONCLUSIONS

Differences in HPV-AFs or ASRs of OPC cannot be explained by differences in the prevalence of oral HPV infection across healthy populations. Consistent research on determinants of oral HPV prevalence, acquisition, clearance, and persistence is warranted.

Mucosal and cutaneous Human Papillomavirus seroprevalence among adults in the prevaccine era in Germany - Results from a nationwide population-based survey

BACKGROUND

Human Papillomavirus (HPV) vaccination of girls was introduced in Germany in 2007. However, data on the distribution of vaccine-relevant HPV types in the general population in Germany in the prevaccine era are limited.

METHODS

Serum samples collected during the German National Health Interview and Examination Survey 1998 (GNHIES98), a nationally representative study including men and women aged 18-79 years, were tested for antibodies to 19 mucosal and cutaneous HPV types. Multivariable regression models were developed to identify associations between demographic and behavioral characteristics and HPV seropositivity.

RESULTS

Of the 6517 serum samples tested, almost a quarter was seropositive for at least one of the nine HPV vaccine types with no clear age-pattern. HPV-6 and HPV-59 were the most common mucosal types, while HPV-1 and HPV-4 were the most common cutaneous HPV types. Factors independently associated with HPV-16 seroprevalence were seropositive to other sexually transmitted infections and lifetime number of sex partners, as well as urbanity (only among females).

CONCLUSIONS

Prevalence of naturally acquired antibodies to HPV types which can be prevented by vaccination is high in both sexes and all age groups. These data can serve as baseline estimates to evaluate the population-level impact of the current vaccination strategy.

Increased risk of HPV-associated genital cancers in men and women as a consequence of pre-invasive disease

To assess the excess risk of HPV-associated cancer (HPVaC) in two at-risk groups-women with a previous diagnosis of high grade cervical intraepithelial neoplasia (CIN3) and both men and women treated for non-cervical pre-invasive anogenital disease. All CIN3 cases diagnosed in 1989-2015 in Scotland were extracted from the Scottish cancer registry (SMR06). All cases of pre-invasive penile, anal, vulval, and vaginal disease diagnosed in 1990-2015 were identified within the NHS pathology databases in the two largest NHS health boards in Scotland. Both were linked to SMR06 to extract subsequent incidence of HPVaC following the diagnosis of CIN3 or pre-invasive disease. Standardised incidence ratios were calculated for the risk of acquiring HPVaC for the two at-risk groups compared to the general Scottish population. Among 69,714 females in Scotland diagnosed with CIN3 (890,360.9 person-years), 179 developed non-cervical HPVaC. CIN3 cases were at 3.2-fold (95% CI: 2.7 to 3.7) increased risk of developing non-cervical HPVaC, compared to the general female population. Among 1,235 patients diagnosed with non-cervical pre-invasive disease (9,667.4 person-years), 47 developed HPVaC. Individuals with non-cervical pre-invasive disease had a substantially increased risk of developing HPVaC - 15.5-fold (95% CI: 11.1 to 21.1) increased risk for females and 28-fold (11.3 to 57.7) increased risk for males. We report a significant additional risk of HPV-associated cancer in those have been diagnosed with pre-invasive HPV-associated lesions including but not confined to the cervix. Uncovering the natural history of pre-invasive disease has potential for determining screening, prevention and treatment.

How confident can we be in the current guidelines for exiting cervical screening?

Current US guidelines recommend against cervical screening beyond age 65 in women who have had adequate negative screening. In anticipation of the next round of evidence review and guideline updates, we provide a critical review of the evidence supporting the exiting recommendation in the US, highlighting both practice changes and new insights into the epidemiology and natural history of HPV and cervical cancer. Current recommendations are based, by necessity, on cytology alone, and will be limited in generalizability to evolving screening strategies with co-testing and primary HPV testing. The lack of empirical data to define what constitutes 'adequate recent screening with negative results' is compounded by difficulties in predicting future risk without consideration of concepts of HPV latency and cohort effects of changing sexual behaviour in US women over time. We urge caution in extrapolating past risk experience in post-menopausal women to today's population, and suggest study designs to strengthen the evidence base in well-screened older women. We further recommend building the qualitative evidence base to better define the harms and benefits of screening among older women. Extending the lifetime of screening is a matter of finding the appropriate balance of benefits of cancer reduction and limitation of harms and costs of 'overscreening'. This will require moving beyond current emphasis on number of colposcopies as the metric of harm. Our commentary is meant to stimulate intellectual debate regarding the certainty of our existing knowledge base and set clear research priorities for the future.

Natural History of HPV Infection across the Lifespan: Role of Viral Latency

Large-scale epidemiologic studies have been invaluable for elaboration of the causal relationship between persistent detection of genital human papillomavirus (HPV) infection and the development of invasive cervical cancer. However, these studies provide limited data to adequately inform models of the individual-level natural history of HPV infection over the course of a lifetime, and particularly ignore the biological distinction between HPV-negative tests and lack of infection (i.e., the possibility of latent, undetectable HPV infection). Using data from more recent epidemiological studies, this review proposes an alternative model of the natural history of genital HPV across the life span. We argue that a more complete elucidation of the age-specific probabilities of the alternative transitions is highly relevant with the expanded use of HPV testing in cervical cancer screening. With routine HPV testing in cervical cancer screening, women commonly transition in and out of HPV detectability, raising concerns for the patient and the provider regarding the source of the positive test result, its prognosis, and effective strategies to prevent future recurrence. Alternative study designs and analytic frameworks are proposed to better understand the frequency and determinants of these transition pathways.