Modeling the impact of budget limitation on the screening and treatment pathway of HPV-induced precancerous cervical lesions.

Cervical cancer in women remains a major public health challenge in sub-Saharan Africa, where both the late diagnoses and limited financial resources hinder effective prevention and treatment. We propose an economic-epidemiological model that integrates the care pathway for cervical lesions and the financial ability to access different treatment stages. Analytical results establish the existence of a basic economic threshold $ \mathcal{R}_0 $, whose value determines whether the system sustains preventive care or collapses into diagnostic failure. We show that a backward bifurcation can occur when $ \mathcal{R}_0 < 1 $, leading to the coexistence of two stable equilibrium points. Furthermore, we establish the global stability of the system collapse equilibrium when $ \mathcal{R}_0 \leq 1 $ under specific conditions. Sensitivity analysis identifies key economic parameters such as screening subsidy, treatment cost, and patient contribution to the billing account that critically influence model dynamics. Numerical simulations estimate that a minimum subsidy level of approximately 13.1% of the human papillomavirus (HPV) test cost is required to ensure system viability ($ \mathcal{R}_0 > 1 $) and prevent long-term collapse of screening coverage. We further decompose the total treatment cost across the care stages and formulate an optimization problem to determine the optimal allocation of government subsidies, minimizing treatment costs while ensuring 90% coverage of women who test positive for HPV. The results show that the optimal strategy requires the government to cover 21.65% of the total treatment cost, mainly focusing on the eligibility test and Large loop excision of the transformation zone (LLETZ) treatment. These findings highlight the importance of targeted subsidies to guarantee both accessibility and financial sustainability in the treatment of precancerous cervical lesions.