A pilot study of repeated 5-aminolevulinic acid photodynamic therapy for cervical intraepithelial neoplasia by a newly developed intravaginal irradiation system

The pilot study was performed to assess the usefulness of a newly developed patientand physician-friendly intravaginal irradiation system for photodynamic therapy with 5-aminolevulinic acid (5-ALA PDT) for cervical intraepithelial neoplasia (CIN). We used an intravaginal balloon applicator to make the cervix upright and to adjust the position and direction of the laser source in the vagina, resulting in minimal patient discomfort and minimal effort required by the physician during irradiation. Ten outpatients of CIN2 or 3 with high-risk human papillomavirus (HPV) infection without a history of HPV vaccination were treated by 5-ALA PDT. Each patient underwent PDT four times every two weeks. Nine patients showed pathological improvement, and the HPV clearance rate was 80%, and no recurrence was observed at two-years follow-up. Serum anti-HPV16 antibodies were detected in seven patients, and the antibody levels of three patients were high, equivalent to those acquired after HPV vaccination. Our newly developed irradiation system enabled easy repeat 5-ALA PDT in the outpatient clinic resulting in the improvement of CIN lesions and HPV clearance. Our results also suggested that repeated 5-ALA PDT might enhance HPV antibody production in CIN patients.