Introduction
Cervical cancer disproportionately affects women in low-income and middle-income countries (LMICs). Of the 311 000 total global cervical cancer deaths in 2018, nearly 90% were reported in LMICs, with this burden of disease expected to increase without meaningful intervention.1 These disparities are largely due to differing levels of accessibility to effective prevention, screening and treatment strategies. For example, over 80% of high-income countries have an established cervical cancer screening programme while less than 50% of LMICs do, achieving average screening coverages of 63% and 19%, respectively.2 What makes these low rates of coverage in LMICs so troubling is that cervical cancer is an almost entirely preventable disease. Practically all cases are caused by human papillomavirus (HPV) types for which an effective vaccine exists.3 Furthermore, the disease’s extended natural progression from persistent HPV infection to precancerous cervical lesions, defined as ranging from low to high grade cervical intraepithelial neoplasia (CIN1–3), occurs over the course of years. Where relevant treatment modalities are accessible, early detection and remediation are thus possible within a relatively large window of time prior to the development of invasive cancer.
To address this global health inequity, in November 2020, the WHO announced its goal to eliminate cervical cancer as a public health problem by the end of the century.1 They have set 90–70–90 targets to be met by every country by 2030. These targets include having 90% of girls vaccinated with the HPV vaccine, 70% of women screened at least twice in their lifetime and 90% of women receiving treatment when precancerous or cancerous cervical lesions are detected through screening.1 Given the limited progress of HPV vaccination campaigns in LMICs and current generations already exposed to HPV, effective screening and treatment programmes are essential to reduce global incidence of cervical cancer and related mortality.
To effectively meet the screening and treatment targets, the WHO recommends a screen-and-treat approach for LMICs.4 The screen-and-treat approach involves screening women for CIN without histological confirmation followed by rapid treatment when results suggest the presence of precancerous lesions, preferably within the same visit. Screening for high-risk HPV types is the preferred method as resources permit, with visual inspection with acetic acid (VIA) and/or visual inspection with Lugol’s iodine (VILI) available as alternative or confirmatory screening methods to HPV testing.4 Referrals are given to women who require treatment for invasive cervical cancer.
Following positive screening test results, precancerous lesions can be removed by excision or destroyed by ablation in outpatient clinics. Given the resource requirements of excisional treatment methods, the WHO recommends that ablative techniques be prioritised for eligible patients when available.5 The two primary ablative techniques recommended are cryotherapy and TA. Cryotherapy is an ablative technique that destroys tissue by freezing it using nitrous oxide or carbon dioxide gas. These gas-based units have been associated with inefficiencies in LMICs due to the continuous costs, procurement challenges and transportation issues of the gas tanks.6 TA, also known as thermocoagulation and cold coagulation, is an ablative technique with comparable efficacy to cryotherapy that destroys tissue by heating it.7 8 As with cryotherapy, it can be performed by a variety of medical providers and does not require anaesthesia. TA is relatively portable given its light weight and can be battery powered, enabling greater reliability in low-resource settings. As it does not use disposable parts or gas tanks, this method does not require continuous costs beyond maintenance, making it more feasible across healthcare settings, including community care and rural contexts.6
In 2019, TA was endorsed by the WHO guidelines for the treatment of precancerous lesions in LMICs based on early evidence of safety and efficacy, and its simplicity of use in screen-and-treat strategies. Yet, questions remain about the potential harms of overtreatment. Screen-and-treat programmes that use high-risk HPV tests (95% sensitivity and 84% specificity) and/or VIA tests (60% sensitivity and 84% specificity) result in overtreatment when all screened positive women are treated.5 Overtreatment is defined as the percentage of women treated despite having no true lesions or lesions graded as CIN1, given that a large proportion of the latter would resolve without treatment. Reported rates of overtreatment from LMICs ranged from 30% to 69%.9–12 The high potential for overtreatment highlights the need to consider treatment side effects and patient acceptability alongside efficacy and logistical concerns when weighing the risks and benefits of different treatment options within screen-and-treat strategies.
This systematic review and meta-synthesis summarises rates of side effects and patient acceptability measures among women in LMICs receiving TA to treat suspected or confirmed precancerous lesions following cervical cancer screening.