Nicole G Campos

A cervical cancer control strategy for lower-resource settings: interventions to complement one-dose HPV vaccination

Abstract One-dose prophylactic HPV vaccination of pre-adolescents may reduce cervical cancer deaths dramatically in lower-resource settings, but the benefits of achieving immediate high coverage among pre-adolescents would not be realized for 20 to 40 years. Prophylactic vaccine efficacy is reduced after sexual debut, and current therapeutic intervention candidates designed to treat existing HPV infections or precancerous lesions have yielded insufficient evidence to warrant widespread use. However, we are developing a feasible, scalable, high-quality cervical screening approach that could prevent hundreds of thousands of deaths, while we work to achieve high coverage of one-dose vaccination for adolescent cohorts. A time-limited “one screen” campaign approach for lower-resource settings could complement parallel efforts to achieve high coverage with one-dose vaccination. This screen-triage-treat strategy would target the highest risk groups of screening age (ie, 25 to 49 years) for once-in-a-lifetime HPV testing of self-collected samples using a low-cost accurate HPV test; subsequent triage relying on extended genotyping and a validated deep-learning algorithm for automated visual evaluation (AVE) would stratify management based on risk to provide treatment for those most likely to develop cancer without overburdening health care systems. Early efficacy of this approach has been demonstrated in 9 countries within the HPV-AVE (PAVE) Study Consortium. We estimate that the cost per death averted of a screen-triage-treat campaign is of similar magnitude to prophylactic vaccination. We do not envision perpetual investment in ubiquitous brick-and-mortar screening programs if “one dose, one screen” is implemented with high coverage and targets the highest-risk populations. In collaboration with in-country stakeholders, efforts to ensure acceptability, risk communication, and cost-effectiveness are underway.

Choosing the optimal HPV vaccine: The health impact and economic value of the nonavalent and bivalent HPV vaccines in 48 Gavi‐eligible countries

AbstractThe human papillomavirus (HPV) vaccines may provide some level of cross‐protection against high‐risk HPV genotypes not directly targeted by the vaccines. We evaluated the long‐term health and economic impacts of routine HPV vaccination using either the nonavalent HPV vaccine or the bivalent HPV vaccine in the context of 48 Gavi‐eligible countries. We used a multi‐modeling approach to compare the bivalent with or without cross‐protection and the nonavalent HPV vaccine. The optimal, that is, most cost‐effective, vaccine was the vaccine with an incremental cost‐effectiveness ratio below the per‐capita gross domestic product (GDP) for each country. By 2100 and assuming 70% HPV vaccination coverage, a bivalent vaccine without cross‐protection, a bivalent vaccine with favorable cross‐protection and the nonavalent vaccine were projected to avert 14.9, 17.2 and 18.5 million cumulative cases of cervical cancer across all 48 Gavi‐eligible countries, respectively. The relative value of the bivalent vaccine compared to the nonavalent vaccine increased assuming a bivalent vaccine conferred high cross‐protection. For example, assuming a cost‐effectiveness threshold of per‐capita GDP, the nonavalent vaccine was optimal in 83% (n = 40) of countries if the bivalent vaccine did not confer cross‐protection; however, the proportion of countries decreased to 63% (n = 30) if the bivalent vaccine conferred high cross‐protection. For lower cost‐effectiveness thresholds, the bivalent vaccine was optimal in a greater proportion of countries, under both cross‐protection assumptions. Although the nonavalent vaccine is projected to avert more cases of cervical cancer, the bivalent vaccine with favorable cross‐protection can prevent a considerable number of cases and would be considered a high‐value vaccine for many Gavi‐eligible countries.

A study of the risks of CIN3+ detection after multiple rounds of HPV testing: Results of the 15‐year cervical cancer screening experience at Kaiser Permanente Northern California

Many countries are transitioning to HPV testing for cervical cancer screening, despite a lack of long‐term experience. To anticipate multi‐round screening performance, we analyzed 15‐year HPV testing results at Kaiser Permanente Northern California (KPNC). We evaluated HPV test result patterns among women aged 30–64 undergoing triennial HPV/cytology cotesting at KPNC during 2003–2018. We calculated incidence rates and proportion of CIN3+ diagnoses associated with the most frequent HPV testing patterns overall and stratified by age. From 2003 to 2018, a total of 1,361,581 women had a valid HPV test result, and 7,087 were diagnosed with CIN3+. Incidence rates of CIN3+ after HPV positivity were lowest when HPV detection was new and highest in women with prevalent infections (770 vs. 13,910/100,000 person‐years). Repeat test negativity reduced subsequent incidence rates of CIN3+ to extremely low levels (18/100,000 person‐years following four consecutive negative results). For mixed patterns of positivity/negativity, the recency and frequency of positive tests were associated with increased rates of CIN3+ diagnosis. Most CIN3+ cases (76%) were diagnosed in women who were positive at baseline (the first known positive HPV result); 16% were attributed to apparent newly detected infections and 3% to possible reappearing infections. These results corroborate previous findings that current HPV positivity, particularly when prevalent rather than new, is associated with the highest rates of CIN3+. In a screening program implementing HPV testing, most CIN3+ is detected at the first HPV positive test.

The cost-effectiveness of human papillomavirus self-collection among cervical cancer screening non-attenders in El Salvador

Cervical cancer screening with human papillomavirus (HPV) DNA testing has been incorporated into El Salvador's national guidelines. The feasibility of home-based HPV self-collection among women who do not attend screening at the clinic (i.e., non-attenders) has been demonstrated, but cost-effectiveness has not been evaluated. Using cost and compliance data from El Salvador, we informed a mathematical microsimulation model of HPV infection and cervical carcinogenesis to conduct a cost-effectiveness analysis from the societal perspective. We estimated the reduction in cervical cancer risk, lifetime cost per woman (2017 US$), life expectancy, and incremental cost-effectiveness ratio (ICER, 2017 US$ per year of life saved [YLS]) of a program with home-based self-collection of HPV (facilitated by health promoters) for the 18% of women reluctant to screen at the clinic. The model was calibrated to epidemiologic data from El Salvador. We evaluated health and economic outcomes of the self-collection intervention for women aged 30 to 59 years, alone and in concert with clinic-based HPV provider-collection. Home-based self-collection of HPV was projected to reduce population cervical cancer risk by 14% and cost $1210 per YLS compared to no screening. An integrated program reaching 99% coverage with both provider- and home-based self-collection of HPV reduced cancer risk by 74% (compared to no screening), and cost $1210 per YLS compared to provider-collection alone. Self-collection facilitated by health promoters is a cost-effective strategy for increasing screening uptake in El Salvador.

The development of “automated visual evaluation” for cervical cancer screening: The promise and challenges in adapting deep‐learning for clinical testing

AbstractThere is limited access to effective cervical cancer screening programs in many resource‐limited settings, resulting in continued high cervical cancer burden. Human papillomavirus (HPV) testing is increasingly recognized to be the preferable primary screening approach if affordable due to superior long‐term reassurance when negative and adaptability to self‐sampling. Visual inspection with acetic acid (VIA) is an inexpensive but subjective and inaccurate method widely used in resource‐limited settings, either for primary screening or for triage of HPV‐positive individuals. A deep learning (DL)‐based automated visual evaluation (AVE) of cervical images has been developed to help improve the accuracy and reproducibility of VIA as assistive technology. However, like any new clinical technology, rigorous evaluation and proof of clinical effectiveness are required before AVE is implemented widely. In the current article, we outline essential clinical and technical considerations involved in building a validated DL‐based AVE tool for broad use as a clinical test.

Potential effectiveness of a therapeutic HPV intervention campaign in Uganda

AbstractCervical cancer is a major source of morbidity and mortality in Uganda. In addition to prophylactic HPV vaccination, secondary prevention strategies are needed to reduce cancer burden. We evaluated the potential cancer reductions associated with a hypothetical single‐contact therapeutic HPV intervention—with 70% coverage and variable efficacy [30%‐100%]—using a three‐stage HPV modeling framework reflecting HPV and cervical cancer burden in Uganda. In the reference case, we assumed prophylactic preadolescent HPV vaccination starting in 2020 with 70% coverage. A one‐time therapeutic intervention targeting 35‐year‐old women in 2025 (not age‐eligible for prophylactic vaccination) averted 1801 cervical cancers per 100 000 women over their lifetime (100% efficacy) or 533 cancers per 100 000 (30% efficacy). Benefits were considerably smaller in birth cohorts eligible for prophylactic HPV vaccination (768 cases averted per 100 000 at 100% efficacy). Evaluating the population‐level impact over 40 years, we found introduction of a therapeutic intervention in 2025 with 100% efficacy targeted annually to 30‐year‐old women averted 139 000 incident cervical cancers in Uganda. This benefit was greatly reduced if efficacy was lower (30% efficacy; 41 000 cases averted), introduction was delayed (2040 introduction; 72 000 cases averted) or both (22 000 cases averted). We demonstrate the potential benefits of a single‐contact HPV therapeutic intervention in a low‐income setting, but show the importance of high therapeutic efficacy and early introduction timing relative to existing prophylactic programs. Reduced benefits from a less efficacious intervention may be somewhat offset if available within a shorter time frame.

Real-World HPV Vaccine Effectiveness Studies: Guideposts for Interpretation of Current and Future Studies

Impact of COVID-19-related care disruptions on cervical cancer screening in the United States

Objectives To quantify the secondary impacts of the COVID-19 pandemic disruptions to cervical cancer screening in the United States, stratified by step in the screening process and primary test modality, on cervical cancer burden. Methods We conducted a comparative model-based analysis using three independent NCI Cancer Intervention and Surveillance Modeling Network cervical models to quantify the impact of eight alternative COVID-19-related screening disruption scenarios compared to a scenario of no disruptions. Scenarios varied by the duration of the disruption (6 or 24 months), steps in the screening process being disrupted (primary screening, surveillance, colposcopy, excisional treatment), and primary screening modality (cytology alone or cytology plus human papillomavirus “cotesting”). Results The models consistently showed that COVID-19-related disruptions yield small net increases in cervical cancer cases by 2027, which are greater for women previously screened with cytology compared with cotesting. When disruptions affected all four steps in the screening process under cytology-based screening, there were an additional 5–7 and 38–45 cases per one million screened for 6- and 24-month disruptions, respectively. In contrast, under cotesting, there were additional 4–5 and 35–45 cases per one million screened for 6- and 24-month disruptions, respectively. The majority (58–79%) of the projected increases in cases under cotesting were due to disruptions to surveillance, colposcopies, or excisional treatment, rather than to primary screening. Conclusions Women in need of surveillance, colposcopies, or excisional treatment, or whose last primary screen did not involve human papillomavirus testing, may comprise priority groups for reintroductions.

Different human papillomavirus types share early natural history transitions in immunocompetent women

AbstractNecessary stages of cervical carcinogenesis include acquisition of a carcinogenic human papillomavirus (HPV) type, persistence associated with the development of precancerous lesions, and invasion. Using prospective data from immunocompetent women in the Guanacaste HPV Natural History Study (NHS), the ASCUS‐LSIL Triage Study (ALTS) and the Costa Rica HPV Vaccine Trial (CVT), we compared the early natural history of HPV types to inform transition probabilities for health decision models. We excluded women with evidence of high‐grade cervical abnormalities at any point during follow‐up and restricted the analysis to incident infections in all women and prevalent infections in young women (aged <30 years). We used survival approaches accounting for interval‐censoring to estimate the time to clearance distribution for 20 529 HPV infections (64% were incident and 51% were carcinogenic). Time to clearance was similar across HPV types and risk classes (HPV16, HPV18/45, HPV31/33/35/52/58, HPV 39/51/56/59 and noncarcinogenic HPV types); and by age group (18‐29, 30‐44 and 45‐54 years), among carcinogenic and noncarcinogenic infections. Similar time to clearance across HPV types suggests that relative prevalence can predict relative incidence. We confirmed that there was a uniform linear association between incident and prevalent infections for all HPV types within each study cohort. In the absence of progression to precancer, we observed similar time to clearance for incident infections across HPV types and risk classes. A singular clearance function for incident HPV infections has important implications for the refinement of microsimulation models used to evaluate the cost‐effectiveness of novel prevention technologies.

Adapting a model of cervical carcinogenesis to self-identified Black women to evaluate racial disparities in the United States

Abstract Background Self-identified Black women in the United States have higher cervical cancer incidence and mortality than the general population, but these differences have not been clearly attributed across described cancer care inequities. Methods A previously established microsimulation model of cervical cancer was adapted to reflect demographic, screening, and survival data for Black US women and compared with a model reflecting data for all US women. Each model input with stratified data (all-cause mortality, hysterectomy rates, screening frequency, screening modality, follow-up, and cancer survival) was sequentially replaced with Black-race specific data to arrive at a fully specified model reflecting Black women. At each step, we estimated the relative contribution of inputs to observed disparities. Results Estimated (hysterectomy-adjusted) cervical cancer incidence was 8.6 per 100 000 in the all-race model vs 10.8 per 100 000 in the Black-race model (relative risk [RR] = 1.24, range = 1.23-1.27). Estimated all-race cervical cancer mortality was 2.9 per 100 000 vs 5.5 per 100 000 in the Black-race model (RR = 1.92, range = 1.85-2.00). We found the largest contributors of incidence disparities were follow-up from positive screening results (47.3% of the total disparity) and screening frequency (32.7%). For mortality disparities, the largest contributor was cancer survival differences (70.1%) followed by screening follow-up (12.7%). Conclusion To reduce disparities in cervical cancer incidence and mortality, it is important to understand and address differences in care access and quality across the continuum of care. Focusing on the practices and policies that drive differences in treatment and follow-up from cervical abnormalities may have the highest impact.

Initial evaluation of a new cervical screening strategy combining human papillomavirus genotyping and automated visual evaluation: the Human Papillomavirus–Automated Visual Evaluation Consortium

Abstract The HPV-Automated Visual Evaluation Consortium is validating a cervical screening strategy enabling accurate cervical screening in resource-limited settings. A rapid, low-cost human papillomavirus (HPV) assay permits sensitive HPV testing of self-collected vaginal specimens; HPV-negative women are reassured. Triage of positive participants combines HPV genotyping (4 groups in order of cancer risk) and visual inspection assisted by automated cervical visual evaluation that classifies cervical appearance as severe, indeterminate, or normal. Together, the combination predicts which women have precancer, permitting targeted management to those most needing treatment. We analyzed CIN3+ yield for each HPV-Automated Visual Evaluation risk level (HPV genotype crossed by automated cervical visual evaluation classification) from 9 clinical sites (Brazil, Cambodia, Dominican Republic, El Salvador, Eswatini, Honduras, Malawi, Nigeria, and Tanzania). Data from 1832 HPV-positive participants confirmed that HPV genotype and automated cervical visual evaluation classification strongly and independently predict risk of histologic CIN3+. The combination of these low-cost tests provided excellent risk stratification, warranting pre-implementation demonstration projects.

Validation of a Lab-free Low-cost Screening Test for Prevention of Cervical Cancer

The purpose of this study is to validate Automated Visual Evaluation (AVE), specifically the CINFinder version developed by DL Analytics, a point-of-care screening and triage diagnostic tool for cervical cancer based on the assessment of digital images through artificial intelligence. Several teams around the world have developed versions of AVE as a triage technology but none as a screening tool.