The effect of local photodynamic therapy with 5-aminolevulinic acid in treating different grades of cervical intraepithelial neoplasia

Abstract

Background: Cervical intraepithelial neoplasia (CIN) is a precursor lesion of cervical cancer. Traditional treatments for CIN might have negative effects on cervical anatomical structure and physiological function. Topical 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) is a novel, non-invasive targeted therapy for intraepithelial lesions. This study aims to evaluate and compare the efficacy and safety of 5-ALA PDT for different grades of CIN.

Methods: A retrospective study of 183 patients aged 19-50 with histologically confirmed CIN and receiving ALA-PDT was conducted. ALA-PDT was performed with 20% ALA thermosensitive gel and irradiation at a wavelength of 635 nm and density of 80-100 J/cm². ALA-PDT was conducted every 7-10 days for 4-6 times. Patients were followed up three, six, nine, and twelve months after treatment. The effect was evaluated through HPV genotyping, ThinPrep cytology test (TCT), and colposcopy-directed biopsy.

Results: The HPV clearance rate was 71.0% (130/183) at the six-month follow-up and 84.5% (147/174) at the 12-month follow-up. The complete lesion remission (CR) rate was 90.2% (165/183). No statistically significant differences concerning the CR rate (P>0.05) or HPV clearance rates (P>0.05) were observed in CIN I, CIN II, and CIN III. In women with CIN III, gland involvement was revealed to be associated with a significantly lower HPV clearance rate (63.16% vs. 92.60%, P= 0.036) at the 12-month follow-up. Our study showed that the atypical vessels seemed to be a risk factor for HPV clearance rate in the CIN II group at six-month follow-up, although the difference was not statistically significant (P= 0.089). During the follow-up, 13 cases had persistent lesions (7.1%), four cases recurred (2.3%), and none of the patients progressed. The study also showed that the efficacy of PDT in the treatment of patients with CIN III involving glands was comparable to that of CKC (P>0.05).

Conclusions: ALA-PDT is an effective andsafe treatment for CIN, and responseis unaffected by the grade of lesions. However, for patients with atypical vessels and glandular involvement, the effect of PDT seems to be poorer.

Keywords: 5-aminolevulinic acid; Atypical vessels; Cervical intraepithelial neoplasia; Gland involvement; Human papillomavirus; Photodynamic therapy.