Evaluation of efficacy and optimal therapeutic parameters of ALA-PDT in the management of HPV-associated cervical intraepithelial neoplasia grade I.

Objective: This study aimed to address three clinically relevant questions in the management of HPV-associated cervical intraepithelial neoplasia grade I (CIN I): whether aminolevulinic acid photodynamic therapy (ALA-PDT) is effective and safe for CIN I, which combination of ALA application time and light exposure duration provides the optimal therapeutic effect, and whether specific HPV subtypes are associated with treatment outcomes. Methods: We enrolled 240 patients diagnosed with CIN I via colposcopy and pathology from June 2021 to June 2023. Patients were divided into four groups based on ALA application time and light exposure duration: Group A1 (3-hour application, 30-minute light exposure), Group A2 (3-hour application, 40-minute light exposure), Group B1 (5-hour application, 30-minute light exposure), and Group B2 (5-hour application, 40-minute light exposure), with 60 patients per group. A 20% ALA solution was used, and irradiation was performed with 635nm red light. Treatment was administered every 2 weeks for four sessions. Patients were followed for 12 months after treatment. HPV testing, TCT, and colposcopy were performed at 3 and 6 months to assess treatment response, while recurrence, progression, and safety outcomes were monitored throughout the 12-month follow-up period. Cure was defined as the absence of abnormalities in TCT, colposcopic findings, and pathological CIN 6 months post-treatment. Results: At 3 and 6 months post-treatment, HPV positivity rates decreased and negative conversion rates increased significantly across all groups, with the greatest improvements observed in Group B2 (P<0.05). Additionally, the proportions of HPV16 and HPV18 types decreased significantly in all groups, with the largest reduction in Group B2. Other high-risk HPV types, such as HPV31 and HPV33, also showed significant reductions (P<0.05). Group B2 had the highest cure rate and lowest recurrence rate among all groups (P<0.05). No significant differences were observed in progression rates or incidence of adverse reactions across groups (P>0.05). HPV16 and HPV18 were positively correlated with the cure rate (correlation coefficients of 0.432 and 0.421, respectively; P<0.05). Conclusion: ALA-PDT is effective for treating HPV-associated CIN I, with optimal parameters of a 5-hour ALA application and 40-minute light exposure.