Background
 
Cervical cancer is the leading cause of cancer death among women in Zambia, where widespread HIV infection is a major driver of elevated cervical cancer risk. However, the contribution of HIV to Zambia’s cervical cancer burden, and the extent to which antiretroviral therapy (ART) has mitigated this burden, remain poorly quantified.
Objectives
This study aims to quantify the dual burden of cervical cancer and HIV in Zambia by estimating the proportion of cancer cases directly attributable to HIV infection.
Methods
We adapted HPVsim, an existing open-source mathematical model that simulates the natural history of human papillomavirus (HPV) and cervical cancer, to capture the dual burden of cervical cancer and HIV in Zambian women. We extended HPVsim by incorporating country-specific age- and sex-stratified HIV incidence data and modeled how HIV alters cervical disease progression through CD4 cell count-dependent modification of HPV susceptibility and disease severity. We calibrated the model to GLOBOCAN estimates for cervical cancer incidence and age-specific cancer cases in 2020, as well as cervical cancer incidence rate ratios by HIV status estimated from the Zambian Cancer Registry.
Results
We estimated that by 2025, about half of all cervical cancer cases in Zambia could be attributed to HIV co-infection. Scale-up of antiretroviral therapy (ART) prevented 8% of cervical cancer cases among women with HIV. Despite substantial ART coverage, cervical cancer incidence remains high, particularly among women with HIV.
Conclusion
Despite the modest protective effect of ART, HIV remains a primary driver of cervical cancer in Zambia by accounting for 50% of cases. HIV-stratified prevention strategies will be essential for Zambia to achieve the World Health Organization’s cervical cancer elimination targets
 

Median model estimates of cervical cancer incidence rates per 100,000 women under all three scenarios