To the Editor
We read with interest the recently published article by Cruz et al1 entitled “Randomized, double-blind, placebo-controlled clinical trial for evaluating the efficacy of fractional CO2 laser compared with topical estriol in the treatment of vaginal atrophy in postmenopausal women”.
This study aimed to evaluate the efficacy of fractional CO2 vaginal laser treatment and compare it with local estrogen therapy, and the combination of both treatments for vulvovaginal atrophy (VVA). The regenerative effects of intravaginal fractional CO2 laser on the vaginal epithelium and lamina propria in postmenopausal women with VVA were previously reported.2 Microablative fractional CO2 laser has been demonstrated to be feasible, efficacious, and safe in improving VVA-related symptoms in postmenopausal women at 12 weeks of follow-up.3 In addition, this technique caused a significant decrease of dyspareunia related to the vaginal dryness, and it was consequently associated with a consistent improvement in sexual function and satisfaction of menopausal women with VVA.4
The current study is to be commended for being the first randomized controlled trial. However, we deem that some methodological flaws are present and some details should be more extensively explained to allow a more thorough interpretation of the findings.
Firstly, no sample size calculation has been reported in the statistical analysis, and this is hardly acceptable when performing a RCT. Ideally, a study should be large enough to have a high chance (power) to identify as statistically significant a clinically important difference and especially if such a difference exists. Thus, it would be helpful to understand why the authors considered 15 patients per arm enough to draw their conclusions on the outcomes achieved with the different treatments.
Secondly, we deem that clarification about blinding is also needed. In our experience, the CO2 laser procedure is always associated with the presence of some smoke and burning odor, and with the feeling of heat by the patient. Therefore, it seems difficult to comprehend that both the patient and the physician who performed the laser treatment are actually blinded. We believe that the presence of an assessor-blinded physician would be a better choice to reduce this bias.