Karen Canfell

The impact of HIV on cervical cancer elimination in KwaZulu-Natal: a comparative modeling analysis

Abstract Background Achieving cervical cancer (CC) elimination requires addressing disparities in CC burden for women living with HIV (WLHIV) and how disparities evolve in the context of antiretroviral therapy (ART) scale-up. To inform CC elimination for high HIV prevalence regions, we modeled the impact of HIV, HIV interventions, and CC interventions in KwaZulu-Natal, South Africa. Methods We used 2 independently developed, dynamic compartmental transmission models of HIV and human papillomavirus (DRIVE and Policy1-Cervix-HIV) calibrated to KwaZulu-Natal. We simulated: a counterfactual without HIV but with observed CC screening and vaccination; and scenarios sequentially adding condom use and voluntary medical male circumcision (VMMC); HIV; observed HIV and CC interventions (status quo); achieving United Nations Programme on HIV/AIDS HIV treatment targets; and achieving World Health Organization (WHO) CC elimination targets. The impact of each scenario was measured as the difference in CC incidence from the previous scenario. Results were reported from 2024 to 2124 as a range between the 2 models; CC elimination was WHO-defined as incidence <4/100 000 women-years. Results For the status quo, CC incidence ranged from 61.30 to 78.96/100 000 women-years in 2024, with the highest incidence among WLHIV (126.8-192.0/100 000). HIV contributed an estimated 29.08-48.87 additional cases per 100 000. Neither model predicted elimination under status quo interventions, but achieving HIV treatment and CC elimination targets could reduce incidence to 1.42-6.25/100 000 women-years in 2124. Conclusions HIV is associated with a population-level increase in CC incidence. However, scaling up ART coverage and CC interventions is expected to significantly reduce the burden of CC overall and among WLHIV. These conclusions are consistent between both models and strengthened by the comparative modeling approach.

State-level disparities in cervical cancer prevention and outcomes in the United States: a modeling study

Abstract Background Despite human papillomavirus (HPV) vaccines’ availability for over a decade, coverage across the United States varies. Although some states have tried to increase HPV vaccination coverage, most model-based analyses focus on national impacts. We evaluated hypothetical changes in HPV vaccination coverage at the national and state levels for California, New York, and Texas using a mathematical model. Methods We developed a new mathematical model of HPV transmission and cervical cancer, creating national- and state-level models, incorporating country- and state-specific vaccination coverage and cervical cancer incidence and mortality. We quantified the national- and state-level impact of increasing HPV vaccination coverage to 80% by 2025 or 2030 on cervical cancer outcomes and the time to elimination defined as less than 4 per 100 000 women. Results Increasing vaccination coverage to 80% in Texas over 10 years could reduce cervical cancer incidence by 50.9% (95% credible interval [CrI] = 46.6%-56.1%) by 2100, from 1.58 (CrI = 1.19-2.09) to 0.78 (CrI = 0.57-1.02) per 100 000 women. Similarly, New York could see a 27.3% (CrI = 23.9%-31.5%) reduction from 1.43 (CrI = 0.93-2.07) to 1.04 (CrI = 0.66-1.53) per 100 000 women, and California a 24.4% (CrI = 20.0%-30.0%) reduction from 1.01 (CrI = 0.66-1.44) to 0.76 (CrI = 0.50-1.09) per 100 000 women. Achieving 80% coverage in 5 years will provide slightly larger and sooner reductions. If the vaccination coverage levels in 2019 continue, cervical cancer elimination could occur nationally by 2051 (CrI = 2034-2064), but state timelines may vary by decades. Conclusion Targeting an HPV vaccination coverage of 80% by 2030 will disproportionately benefit states with low coverage and higher cervical cancer incidence. Geographically focused analyses can better inform priorities.

Disparities in cervical cancer elimination time frames in the United States: a comparative modeling study

Abstract Population-level estimates in time frames for reaching cervical cancer elimination (ie, <4 cases per 100 000 women) in the United States may mask potential disparities in achieving elimination among subpopulations. We used 3 independent Cancer Intervention and Surveillance Modeling Network models to estimate differences in the time to cervical cancer elimination across 7 strata of correlated screening and human papillomavirus vaccination uptake, based on national survey data. Compared with the average population, elimination was achieved at least 22 years earlier for the high-uptake strata and at least 27 years later for the most extreme low-uptake strata. Accounting for correlated uptake impacted the population average time frame by no more than 1 year. Consequently, national average elimination time frames mask substantial disparities in reaching elimination among subpopulations. Addressing inequalities in cervical cancer control could shorten elimination time frames and would ensure more equitable elimination across populations. Furthermore, country-level elimination monitoring could be supplemented by monitoring progress in subpopulations.

The impact of HPV vaccination beyond cancer prevention: effect on pregnancy outcomes

While the benefits of human papillomavirus (HPV) vaccination relating to cervical cancer prevention have been widely documented, recent published evidence is suggestive of an impact on adverse pregnancy outcomes (APOs) in vaccinated mothers and their infants, including a reduction in rates of preterm births and small for gestational age infants. In this review, we examine this evidence and the possible mechanisms by which HPV vaccination may prevent these APOs. Large-scale studies linking HPV vaccination status with birth registries are needed to confirm these results. Potential confounding factors to consider in future analyses include other risk factors for APOs, and historical changes in both the management of cervical precancerous lesions and prevention of APOs. If confirmed, these additional benefits of HPV vaccination in reducing APO rates will be of global significance, due to the substantial health, social and economic costs associated with APOs, strengthening the case for worldwide HPV immunization.

Eliminating Cervical Cancer: Progress and Challenges for High-income Countries

In 2020, the World Health Organization launched a major initiative to eliminate cervical cancer globally. The initiative is built around the three key pillars of human papillomavirus (HPV) vaccination, cervical screening and treatment, with associated intervention targets for the year 2030. The '90-70-90' targets specify that 90% of adolescent girls receive prophylactic HPV vaccination, 70% of adult women receive a minimum twice-in-a-lifetime cervical HPV test and 90% receive appropriate treatment for preinvasive or invasive disease. Modelling has shown that if these targets are met, the elimination of cervical cancer, defined as fewer than four cases per 100 000 women per annum, will be achieved within a century. Many high-income countries are well positioned to eliminate cervical cancer within the coming decades, but few have achieved '90-70-90' and many challenges must still be addressed to deliver these critical interventions effectively. This review considers the current status of cervical cancer control in relation to each of the three elimination pillars in high-income countries and discusses some of the developments that will assist countries in reaching these ambitious targets by 2030.

The past, present and future impact of HIV prevention and control on HPV and cervical disease in Tanzania: A modelling study

Women with HIV have an elevated risk of HPV infection, and eventually, cervical cancer. Tanzania has a high burden of both HIV and cervical cancer, with an HIV prevalence of 5.5% in women in 2018, and a cervical cancer incidence rate among the highest globally, at 59.1 per 100,000 per year, and an estimated 9,772 cervical cancers diagnosed in 2018. We aimed to quantify the impact that interventions intended to control HIV have had and will have on cervical cancer in Tanzania over a period from 1995 to 2070. A deterministic transmission-dynamic compartment model of HIV and HPV infection and natural history was used to simulate the impact of voluntary medical male circumcision (VMMC), anti-retroviral therapy (ART), and targeted pre-exposure prophylaxis (PrEP) on cervical cancer incidence and mortality from 1995-2070. We estimate that VMMC has prevented 2,843 cervical cancer cases and 1,039 cervical cancer deaths from 1995-2020; by 2070 we predict that VMMC will have lowered cervical cancer incidence and mortality rates by 28% (55.11 cases per 100,000 women in 2070 without VMMC, compared to 39.93 with VMMC only) and 26% (37.31 deaths per 100,000 women in 2070 without VMMC compared to 27.72 with VMMC), respectively. We predict that ART will temporarily increase cervical cancer diagnoses and deaths, due to the removal of HIV death as a competing risk, but will ultimately further lower cervical cancer incidence and mortality rates by 7% (to 37.31 cases per 100,000 women in 2070) and 5% (to 26.44 deaths per 100,000 women in 2070), respectively, relative to a scenario with VMMC but no ART. A combination of ART and targeted PrEP use is anticipated to lower cervical cancer incidence and mortality rates to 35.82 and 25.35 cases and deaths, respectively, per 100,000 women in 2070. HIV treatment and control measures in Tanzania will result in long-term reductions in cervical cancer incidence and mortality. Although, in the near term, the life-extending capability of ART will result in a temporary increase in cervical cancer rates, continued efforts towards HIV prevention will reduce cervical cancer incidence and mortality over the longer term. These findings are critical background to understanding the longer-term impact of achieving cervical cancer elimination targets in Tanzania.

Estimating the Natural History of Cervical Carcinogenesis Using Simulation Models: A CISNET Comparative Analysis

Abstract Background The natural history of human papillomavirus (HPV)-induced cervical cancer (CC) is not directly observable, yet the age of HPV acquisition and duration of preclinical disease (dwell time) influences the effectiveness of alternative preventive policies. We performed a Cancer Intervention and Surveillance Modeling Network (CISNET) comparative modeling analysis to characterize the age of acquisition of cancer-causing HPV infections and implied dwell times for distinct phases of cervical carcinogenesis. Methods Using four CISNET-cervical models with varying underlying structures but fit to common US epidemiological data, we estimated the age of acquisition of causal HPV infections and dwell times associated with three phases of cancer development: HPV, high-grade precancer, and cancer sojourn time. We stratified these estimates by HPV genotype under both natural history and CC screening scenarios, because screening prevents cancer development that affects the mix of detected cancers. Results The median time from HPV acquisition to cancer detection ranged from 17.5 to 26.0 years across the four models. Three models projected that 50% of unscreened women acquired their causal HPV infection between ages 19 and 23 years, whereas one model projected these infections occurred later (age 34 years). In the context of imperfect compliance with US screening guidelines, the median age of causal infection was 4.4–15.9 years later compared with model projections in the absence of screening. Conclusions These validated CISNET-CC models, which reflect some uncertainty in the development of CC, elucidate important drivers of HPV vaccination and CC screening policies and emphasize the value of comparative modeling when evaluating public health policies.

Impact of a Human Papillomavirus Vaccination Program within Organized Cervical Cancer Screening: Cohort Study

Abstract Background: We assessed the effectiveness of an HPV (human papillomavirus) vaccination program in lowering cervical abnormality risk, and conferring herd protection. Methods: Retrospective cohort study using linked screening and vaccination administrative health data of the general population of Ancona Province, Italy. We included all female residents born in 1990–1993, eligible for catch-up HPV vaccination up to age 25 years, and adhering to organized screening in 2015–2020 (n = 4,665). Cervical abnormalities rates were compared between: Vaccinated and unvaccinated women, and cohorts with high and low vaccination uptake. Analyses were adjusted for age, country of birth, screening tests number, laboratory, and municipality average income. Main outcomes were ASC-US+ or LSIL+ Pap smears, and CIN1+ or CIN2+ histology. Results: Mean screening age was 26.6±1.5 years, and 1,118 screened women (24.0%) were vaccinated (mean vaccination age 19.2±1.5 years). The diagnosed cervical abnormalities were: 107 LSIL+ (2.3%), 70 CIN1+ (1.5%), and 35 CIN2+ (0.8%). The adjusted odds ratios of LSIL+, CIN1+, and CIN2+ among vaccinated versus unvaccinated women were, respectively: 0.55 [(95% confidence interval (CI), 0.33–0.91)], 0.43 (95% CI, 0.22–0.86), and 0.31 (95% CI, 0.11–0.91). Among the unvaccinated, those in the highest-uptake (45.3%) 1993 cohort, versus the last pre-vaccination 1990 cohort, showed AORs of LSIL+ and CIN1+ of 0.23 (95% CI, 0.10–0.50), and 0.22 (95% CI, 0.07–0.69), respectively. Conclusions: In the first evaluation from Central Italy, catch-up HPV vaccination considerably reduced the risk of all cervical abnormalities diagnosed within organized screening, and conferred an elevated degree of herd protection among unvaccinated women. Impact: The high protection conferred by HPV vaccination suggests the need to update cervical screening.

Participation in the National Cervical Screening Program Among Women Who Gave Birth in New South Wales, Australia by Place of Maternal Birth: A Data Linkage Analysis

ABSTRACT Objective High participation rates in the National Cervical Screening Program (NCSP) by all groups of women are required to ensure the equitable elimination of cervical cancer in Australia. In this study, we examine screening participation of overseas‐born women compared to Australian‐born women who gave birth. Design Population‐based retrospective cohort study using linked health datasets. Setting and Participants Women who gave birth in New South Wales between January 1, 2000 and June 30, 2017. Main Outcome Measures Participation in the NCSP (≥ 1 cytology test) in the 3‐ and 5‐year periods prior to delivery by place of maternal birth, adjusted for multiple socio‐demographic and health characteristics. Results Among the 1 332 669 mothers who gave birth over the study period, overall cervical screening participation in the 3‐ and 5‐year periods prior to delivery was 67.0% and 75.7%, respectively. Participation was lower for overseas‐born mothers compared to Australian‐born mothers for both the 3‐year (57.8% vs. 71.7%; adjusted odds ratio [aOR]: 0.51, 95% confidence interval [CI]: 0.50–0.51) and 5‐year (64.9% vs. 81.2%; aOR: 0.40, 95% CI: 0.40–0.40) participation periods. All groups of overseas‐born women had substantially lower screening participation compared to Australian‐born women, with the lowest relative 3‐year participation in mothers born in Southern/Central Asia (aOR: 0.30, 95% CI: 0.30–0.31), Oceania (aOR: 0.31, 95% CI: 0.30–0.32), North‐East Asia (aOR: 0.49, 95% CI: 0.48–0.50), and New Zealand (aOR: 0.49, 95% CI: 0.48–0.51). Conclusions Overseas‐born women had around half the cervical screening participation in the period prior to birth compared to Australian‐born women. It is likely that opportunities to screen these under‐screened groups during the antenatal period, typically a time of repeated health services contact, are missed.

Cervical cancer treatment outcomes and survival in Botswana by human immunodeficiency virus status: Ipabalele study results

Abstract Background Cervical cancer is a leading morbidity/mortality cause, frequently co-occurring with human immunodeficiency virus (HIV) positivity, in Botswana. We examined long-term outcomes for Ipabalele study participants receiving curative chemoradiation for locally advanced cervical cancer (2015-2019) by HIV status. Methods Clinical and outcome data were collected at baseline, treatment completion, and 3 months thereafter. Patients were followed for up to 5 years. Overall survival (OS) was evaluated using Kaplan-Meier curves and Cox regression. Results The cohort comprised 295 patients (73.8% with HIV, younger at diagnosis [P < .001]) followed for a median of 44.2 months. Complete response was seen in 217/278 (76.1%) patients. Two- and 5-year OS rates were 73.4% and 59.9%, respectively, with no difference by HIV status. OS was associated negatively with advanced disease stage (III: hazard ratio [HR] 13.23, P < .001; IV: HR 7.8, P = .008) and positively with increased radiation (HR 0.977, P = .0005) and chemotherapy (HR 0.85, P = .005). Clinical response was associated negatively with advanced disease (IV: HR 0.113, P = .002) and positively with increased radiation (P = .009). Toxicity did not differ by HIV status. The most common grade-≥-2 non-hematological and hematological toxicities were radiation dermatitis (39.8%) and reduced white blood cell count (66.05%), respectively. Conclusions In this cervical cancer cohort with good HIV status control, treatment outcomes and OS were associated with disease and treatment factors, not the HIV status. Early screening and education regarding treatment protocols are crucial to improve cervical cancer outcomes in Botswana.

Cervical Cancer Elimination in Australia and the Asia Pacific: Progress and Barriers

ABSTRACT Australia has been at the forefront of innovation and implementation of cervical cancer control and is predicted to eliminate cervical cancer by 2035, the first country to achieve elimination using active measures. This is a result of Australia being an early adopter of universal human papillomavirus (HPV) vaccination and early transition to a primary HPV‐based cervical screening program. However, to ensure timely and equitable elimination, disparities in coverage among underserved populations must be addressed, and recent declines in vaccination and screening uptake must be reversed. Improved routine data linkages are required to ensure gaps in participation in subpopulations can be identified. Primary health providers have an important role in checking vaccination and screening status and offering vaccination catch‐up or screening as appropriate. A universal option of self‐collection of an HPV sample for all screen‐eligible people has increased acceptability overall, but further innovative and flexible models of service delivery are required to ensure equitable access for all. Australia has also played an important role in cervical cancer control globally and was a co‐sponsor of the 2020 World Health Assembly resolution to accelerate the global elimination of cervical cancer as a public health problem. In the Indo‐Pacific region, regional frameworks have been developed to advance strategic actions to progress implementation of the global strategy. The Elimination Partnership in the Indo‐Pacific for Cervical Cancer (EPICC), a major initiative supported by the Australian Government and the Minderoo Foundation, provides tailored support to countries, considering local needs and priorities.