Preventive medicine
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Preventive medicine · Mar 2021
From cervical cancer elimination to eradication of vaccine-type human papillomavirus: Feasibility, public health strategies and cost-effectiveness.
The Director-General of the World Health Organization has called for global action towards elimination of cervical cancer as a public health problem. Cervical cancer is caused by human papillomavirus (HPV), an infectious agent with no non-human reservoir. One way to achieve this is through very high levels of vaccine coverage that could enable global eradication of vaccine-type HPV. ⋯ It can be achieved with 90% gender-neutral HPV vaccine coverage together with 95% coverage in high-risk groups such as female sex workers. Such a strategy would likely be cost-effective compared to no vaccination. Although it would be more costly in the short-term than achieving cervical cancer elimination alone, it would save costs in the long-term by removing or at least sharply reducing the need for preventive measures.
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Preventive medicine · Mar 2021
Achieving equity in cervical cancer screening in low- and middle-income countries (LMICs): Strengthening health systems using a systems thinking approach.
The World Health Organization (WHO) is leading a call to action to eliminate cervical cancer by the end of the century through global implementation of two effective evidence-based preventive interventions: HPV vaccination and cervical screening and management (CSM). Models estimate that without intervention, over the next 50 years 12.2 million new cases of cervical cancer will occur, nearly 60% of which are preventable only through CSM. Given that more than 80% of the cervical cancer occurs in low- and middle-income countries (LMICs), scaling up sustainable CSM programs in these countries is a top priority for achieving the global elimination goals. ⋯ As part of the coordinated cervical cancer elimination effort, we applied a systems thinking lens to reflect on our experiences with implementation of HPV-based CSM programs using the WHO health systems framework. While many common health system barriers were identified, the effectiveness of implementation strategies to address them was context dependent; often reflecting differences in stakeholder's belief in the quality of the evidence supporting a CSM algorithm, the appropriateness of the evidence and algorithm to context, and the 'implementability' of the algorithm under realistic assessments of resource availability and constraints. A structured planning process, with early and broad stakeholder engagement, will ensure that shared-decisions in CSM implementation are appropriately aligned with the culture, values, and resource realities of the setting.
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Preventive medicine · Mar 2021
Surveillance systems for monitoring cervical cancer elimination efforts: Focus on HPV infection, cervical dysplasia, cervical screening and treatment.
In order to achieve the global elimination of cervical cancer as a public health problem, close surveillance of progress in public health and clinical activities and outcomes across the three pillars of vaccination, screening and treatment will be required. Surveillance should ideally occur within an integrated system that is planned, funded, and regularly evaluated to ensure it is providing timely, accurate and relevant feedback for action. In this paper, we conceptualise the main public health surveillance objectives as process and outcome measures in each of the three pillars. ⋯ Outcome measures related to the natural history of human papillomavirus (HPV) infection include HPV infection prevalence, precursor cervical lesions and cervical cancers (including stage at diagnosis, cancer incidence and mortality). These outcome measures can be used for monitoring the effectiveness of the three core activities in the short, medium and long term to assess whether these interventions are effectively reducing their occurrence. We discuss possible methods for the surveillance of these measures in the context of country capacity, drawing from examples in Australia, the USA and in low and middle income countries.
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Preventive medicine · Mar 2021
Impact and cost-effectiveness of strategies to accelerate cervical cancer elimination: A model-based analysis.
Following the global call for action by the World Health Organization to eliminate cervical cancer (CC), we evaluated how each CC policy decision in Norway influenced the timing of CC elimination, and whether introducing nonavalent human papillomavirus (HPV) vaccine would accelerate elimination timing and be cost-effective. We used a multi-modeling approach that captured HPV transmission and cervical carcinogenesis to estimate the CC incidence associated with six past and future CC prevention policy decisions compared with a pre-vaccination scenario involving 3-yearly cytology-based screening. Scenarios examined the introduction of routine HPV vaccination of 12-year-old girls with quadrivalent vaccine in 2009, a temporary catch-up program for females aged up to 26 years in 2016-2018 with bivalent vaccine, the universal switch to bivalent vaccine in 2017, expansion to include 12-year-old boys in 2018, the switch from cytology- to HPV-based screening for women aged 34-69 in 2020, and the potential switch to nonavalent vaccine in 2021. ⋯ Cumulatively, subsequent policy decisions accelerated elimination to 2039. According to our modeling assumptions, switching to the nonavalent vaccine would not be considered 'good value for money' at relevant cost-effectiveness thresholds in Norway unless the incremental cost was $19 per dose or less (range: $17-24) compared to the bivalent vaccine. CC control policies implemented over the last decade in Norway may have accelerated the timeframe to elimination by more than 17 years and prevented over 23,800 cases by 2110.
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Preventive medicine · Mar 2021
Treatment approaches for women with positive cervical screening results in low-and middle-income countries.
The primary goal of cervical screening is to identify women with cervical precancers who need treatment to prevent invasive cervical cancer. Cervical cancer screening programs in high-resource settings rely on a multi-step process to reassure the majority of women of low cancer risk and treat the small number of women at high risk of precancer and cancer. The requirement of major resource investment for training and capacity building of multi-step cervical cancer screening programs prevents their introduction in low- and middle-income countries (LMICs). ⋯ While most women below 40 are eligible for ablative procedures, fewer than 50% are eligible by age 50 and ablative treatment is not appropriate over age 50. Excisional treatment is required for women ineligible for ablative treatment. Since screening programs in LMICs necessarily detect invasive cancers, cancer treatment and palliative care needs to be considered as well.