Prognostic factors influencing the cure rate of 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) of High-grade squamous intraepithelial lesions (HSIL): A retrospective cohort study

BACKGROUND: High-grade squamous intraepithelial lesions (HSIL) are key cervical cancer precursors. While effective, traditional treatments may impair fertility. 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) offers a minimally invasive alternative, yet prognostic factors remain unclear. This study evaluated 12-month cure rates and identified predictors of response. METHODS: This retrospective cohort included 174 HSIL patients treated with ALA-PDT and followed for ≥12 months. Data on age, lesion type (CIN2 vs. CIN3), HPV status, prior treatments (including CO₂ laser pretreatment), and concomitant vaginitis were collected. Cure was defined as normal ThinPrep cytology, negative HPV, and histologic regression. Logistic regression and ROC analysis identified predictors. RESULTS: ALA-PDT achieved 88.5% cure rate. CIN3 lesions (OR=0.175, P = 0.012) and prior CO₂ laser ablation (OR=19.024, P = 0.005) were independent predictors. CIN3 patients showed lower HPV clearance. The positive prognostic value of CO₂ laser pretreatment is likely attributable to enhanced drug penetration after lesion debulking, while standardized management of concomitant vaginitis may optimize therapeutic outcomes by reducing local inflammation. Combining lesion type and treatment history improved predictive accuracy (AUC=0.772). CONCLUSION: ALA-PDT is effective for HSIL. CIN3 and prior CO₂ laser ablation are key prognostic factors. Optimizing pretreatment strategies and managing vaginitis may further improve cure rates.