Background:  Ninety percent of cervical cancer deaths occur in low- and middle-income countries (LMICs). Responding to this inequity and to accelerate screening-and-treatment efforts under the global Cervical Cancer Elimination Initiative, the SUCCESS project, supported by Unitaid, introduced WHO-recommended HPV-testing and thermal ablation (HPV-TA) in Burkina Faso, Côte d’Ivoire, Guatemala, and Philippines. 
Objectives: We aimed to explore the integration of these new modalities into existing women’s health services through an embedded implementation study, 2021-23.
Methods: At SUCCESS initiation, prevailing primary screening modalities were VIA (Burkina Faso, Côte d’Ivoire), Pap cytology (Guatemala) and a mix of both (Philippines). Within the wider introduction of HPV-TA in the four countries we analyzed a subset of sites through a hybrid effectiveness-implementation Type III study with parallel convergent mixed-methods. HPV-TA was implemented in both screen-treat and screen-triage-treat approaches, following algorithms recommended in 2019 WHO cervical cancer screening-and-treatment guidelines. The primary outcome was proportion of HPV-positive women returning for treatment/triage within 90 days; secondary outcomes included acceptability and feasibility. 10 sites/country were selected to ensure a maximum variation of characteristics (diverse service provision, rural/urban, facility level, on/off-site laboratories). Sample size for screening, powered at 80% to estimate the primary outcome, was 2200/country. 108 participants were purposively sampled for qualitative data collection, including from among those screened, providers, and facility managers. Women were given the option to self-collect samples. Providers were trained in counselling, sample collection and thermal ablation. We used a customized electronic clinical data collection tool, facility registries, surveys, in-depth and screening exit interviews, and key-informant interviews. Timepoints recorded included sample collection, laboratory turn-around, results disclosure and follow-up. Analysis used descriptive statistics, multi-variate logistic regression and rapid thematic analysis, with stratified analysis for women living with HIV (WLHIV). 
Results: 8600 women were enrolled across the four countries, 12% WLHIV. HPV-positivity rates ranged 8-12% for the general population and was significantly higher for WLHIV at 28-40% (p<0.05). Self-sampling rates ranged 68-94%. The primary outcome was measured at 18% in Côte d’Ivoire, 50% in Guatemala, 52% in Philippines, and 70% in Burkina Faso. Median time from sample-collection to return for any treatment/triage ranged 31-185 days. Receipt of test results >40 days was a significant predictor of women not returning in Côte d’Ivoire (aOR: 0.09 [0.04-0.21]; p<0.001) and in Burkina Faso (aOR: 0.09 [0.07 - 0.36]; p<0.001). Counselling effectiveness, facility cleanliness and self-sampling choice positively influenced acceptability among women, while providers valued self-efficacy in performing new tasks. Feasibility barriers for women included fear, travel time and out-of-pocket costs, and for providers, more onerous record-keeping burden and follow-up communication difficulties. Laboratory personnel cited barriers of managing surge processing and supply chain disruptions. 
Conclusions: Barriers to timely return for evaluation and treatment are diverse, but the length of time in receiving laboratory results by women is a key factor. Nevertheless, HPV-testing and thermal ablation can be transitionally introduced in LMICs using a flexible multi-modality approach which allows complementary fit with existing (sometimes disparate) screening micro-systems while necessary health macro-system transformations like laboratory optimization are implemented.