Comparative study of photodynamic therapy (PDT) of cervical low-grade squamous intraepithelial lesion (LSIL).

Background: Prevention of high-risk HPV (HR-HPV) infection and effective medical intervention of persistent HPV infection and precancerous lesions are critical for the prevention of cervical cancer.

Aims: The aim of this retrospective comparative study was to evaluate the outcomes of ALA PDT and observation only in the management of low-grade squamous intraepithelial lesions (LSIL).

Methods: In PDT Group (n = 138), ALA PDT was applied to patients with colposcopic biopsy confirmed cervical LSIL accompanied with HR-HPV infection longer than 1 year or HPV 16/18 subtype infection. Cervical LSIL only patients received 3 times of ALA PDT and those with concurrent cervical canal or vaginal lesions received 6 times ALA PDT. Control Group (n = 69) received observation only. Colposcopy, TCT and HPV typing were performed before and after treatment. Patients were followed up for up to two years.

Result: The observation group showed 26.1%, 34.8% and 53.6% HR-HPV negative conversion at 3-6, 12 and 24 months, respectively. LSIL regression rate of the observation group was 33.33%, 36.23% and 65.22% at 3-6, 12 and 24 months, respectively. There was 62.32%, 80.56% and 89.22% patients achieved HPV clearance at 3-6, 12 and 24 months after PDT treatment, respectively. The LSIL remission rate was 89.86%, 94.40% and 96.08% at 3-6, 12 and 24 months after ALA PDT, respectively. The abnormal TCT (≧ ASCUS) was reduced from 92% to 10.1%, 4.6% and 3.9% at 3-6, 12 and 24 months after ALA PDT, respectively. The patient age was not a factor affecting the clearance of HPV infection and the LSIL regression rate of PDT treatment.

Conclusions: This study demonstrates that the application of multiple ALA PDT treatments has added value in achieving both short-term and long-term HPV and lesion clearance.