Vaginal epithelial histology before and after fractional CO₂ laser in postmenopausal women: a double-blind, sham-controlled randomized trial

BACKGROUND: Postmenopausal vaginal symptoms affect over 60% of women and may substantially impact a woman's quality of life. Since 2012, fractional CO2 laser has been suggested as a treatment for this indication. Structural assessment of vaginal epithelium using microscopic biopsy examination has been used as a primary outcome measure and surrogate determinant of success of vaginal laser in previous clinical studies.OBJECTIVE: This study aimed to report the effects of laser compared with sham treatment on human vaginal epithelium from postmenopausal women using microscopic examination of tissue biopsies.STUDY DESIGN: This single-center double-blind, sham-controlled randomized controlled trial was performed in a tertiary hospital in Sydney, Australia. A total of 49 postmenopausal women who were symptomatic of at least 1 vaginal symptom (vaginal dryness, burning, itching; dyspareunia; or dryness) were randomized to either laser or sham treatment. For this nested histologic study, participants had a pre-and post-treatment vaginal wall biopsy collected. Biopsy samples were analyzed by 3 independent specialist gynecologic pathologists and categorized as Type 1 (well-estrogenized), 2 (poorly estrogenized), or 3 (combination) mucosae. Other outcomes assessed included symptom severity (visual analog scale for symptoms including most bothersome symptom, and Vulvovaginal Symptom Questionnaire) and Vaginal Health Index. Prespecified secondary analyses of data were performed. Categorical data were analyzed using the Pearson chisquare test (or Fisher exact test if <5 in any category) or related-samples McNemar test for paired nonparametric data. Nonparametric, continuous variables were assessed using Wilcoxon signed-rank test or Mann-Whitney U test, and parametric variables with t test or 1-way analysis of variance as appropriate. All analyses were performed using SPSS software version 26.0 (IBM Corp, Armonk, NY).RESULTS: There was no significant difference in microscopic features of vaginal epithelium following laser or sham treatment (P=.20). Further subgroup analyses of age, menopause type, duration of reproductive life, time since menopause and BMI, still demonstrated no significant difference between laser and sham groups in histological category of vaginal epithelium. Microscopic features at pre-treatment vaginal biopsy were Type 1 in 27% (13/49). There was no significant difference in VAS score for overall vaginal symptom between those classified as Type 1 vs. Type 2/3 (VAS score overall: Type 1 vs. Type 2/3, (48.1 [95% CI 27.0, 69.2] vs. 61.5 [95% CI 49.8, 73.3]; P=.166).CONCLUSION: Data from this double-blind, sham-controlled randomized controlled trial demonstrate that fractional CO2 laser and sham treatment have a comparable histologic effect on vaginal tissue that is not significantly different. Fractional CO2 laser is not significantly different from sham treatment and should not be recommended for clinical use for postmenopausal vaginal symptoms.