Chemical Peeling Therapy Using Phenol for the Cervico-Vaginal Intraepithelial Neoplasia

<b>Objective:</b> This study aimed to validate the use of liquid phenol-based chemical peeling therapy for cervical and vaginal intraepithelial neoplasia (CIN and VaIN, respectively), with the goal of circumventing obstetric complications associated with surgical treatment and to determine the factors associated with treatment resistance. <b>Methods:</b> A total of 483 eligible women diagnosed with CIN, VaIN, or both, participated in this study. Participants underwent phenol-based chemical peeling therapy every 4 weeks until disease clearance. Disease clearance was determined by negative Pap tests for four consecutive weeks or by colposcopy. HPV genotyping was conducted at the onset of the study and after disease clearance in select cases. Our preliminary analysis compared the recurrence and persistence rates between 294 individuals who received phenol-based chemical peeling therapy and 189 untreated patients. <b>Results:</b> At 2 years following diagnosis, persistent disease was observed in 18%, 60%, and 88% of untreated patients with CIN1–3, respectively, and <2% of patients with CIN who received phenol-based chemical peeling therapy. Among 483 participants, 10 immune-suppressed patients required multiple treatments to achieve disease clearance, and 7 were diagnosed with cervical cancer. Of the 466 participants, except those with cancer or immune suppression, the number of treatment sessions until CIN/VaIN clearance ranged from 2 to 42 (average: 9.2 sessions). In total, 43 participants (9.2%) underwent surgical treatment. Six patients (1.3%) experienced recurrence of CIN2 or worse, suggesting that treatment failed in 46 patients (9.9%). No obstetrical complications were noted among the 98 pregnancies following this therapy. Factors associated with resistance to this therapy include immune suppression, ages 35–39 years, higher-grade lesions, and multiple HPV-type infections. <b>Conclusions:</b> Phenol-based therapy is safe and effective for CINs and VaINs. Women aged < 35 years and with persistent CIN1 or CIN2 with a single HPV-type infection are suitable candidates for phenol-based chemical peeling therapy. However, this therapy requires multiple lengthy sessions.