Effect of Fractional Carbon Dioxide vs Sham Laser on Sexual Function in Survivors of Breast Cancer Receiving Aromatase Inhibitors for Genitourinary Syndrome of Menopause

Key Points Question Is vaginal laser treatment safe and effective for genitourinary syndrome of menopause in survivors of breast cancer receiving aromatase inhibitors? Findings In this randomized clinical trial with 84 participants in 2 parallel study groups, both groups received a first-line therapy based on nonhormonal moisturizers and vaginal vibrator stimulation, and participants were randomized to receive 5 weekly sessions of fractional carbon dioxide laser therapy or sham laser therapy. No differences were observed between groups in safety or efficacy outcomes at the 6-month follow-up. Meaning These findings suggest that although vaginal laser treatment was safe, it was not more effective than first-line therapy with placebo treatment in survivors of breast cancer receiving aromatase inhibitors.


Introduction
During the last decades, dysfunction of sexual and vaginal health, including genitourinary syndrome of menopause (GSM), has remained underdiagnosed and undertreated in survivors of breast cancer. 1,2These symptoms are usually worse among survivors of breast cancer compared with women without history of cancer, due to the antiestrogenic effects of chemotherapy, tamoxifen, and aromatase inhibitors. 3In addition, estrogen-based standard treatment for GSM remains controversial in this subset of patients. 4 the last few years, new therapeutic approaches have been designed to relieve GSM symptoms, and vaginal laser therapy is one of the trending options. 5Although most studies conclude that vaginal laser therapy is a safe option, 6,7 safety outcomes are underreported in most studies. 8In a 2022 systematic review, 8 vaginal laser treatment was associated with improved subjective outcomes, such as the dyspareunia (assessed via visual analog scale [VAS]), the Female Sexual Function Index (FSFI), and the Vaginal Health Index (VHI), in the short term; however, most of the assessed studies were single-group before-and-after trials with evidence of low to moderate quality. 8ere is also controversy on the results of objective outcomes, as some studies 9,10 have shown an increase of the epithelial vaginal layer, whereas other studies 11,12 have found no differences between sham and real laser groups.Thus, there is need for sham-controlled randomized clinical trials (RCTs).
The aim of this study was to assess the safety and efficacy of carbon dioxide (CO 2 ) vaginal laser therapy (CLT) compared with sham laser therapy (SLT) after 6 months of follow-up in survivors of breast cancer with GSM receiving aromatase inhibitors.

Methods
This RCT was approved by the institutional review board of the Hospital Clinic of Barcelona, Spain.This study adheres to the European Union Law of Data Protection and was conducted ethically in accordance with the Declaration of Helsinki.Written informed consent was obtained from all participants.This study followed the Consolidated Standards of Reporting Trials (CONSORT) reporting guideline for RCTs.

Study Design
In this prospective, double-blind, sham-controlled, RCT with 2 parallel study groups, both groups received first-line therapy (FLT) based on nonhormonal moisturizers and a vaginal vibrator stimulation, plus 5 monthly sessions of laser treatment with 2 groups, the first receiving fractional CLT and the second receiving SLT.The trial protocol and statistical analysis plan are presented in Supplement 1.

Participants
The study was conducted in the Hospital Clinic of Barcelona, Spain.The inclusion criteria were survivors of breast cancer aged 30 years and older receiving aromatase inhibitors (for Ն6 months); menopause, signs or symptoms of GSM with dyspareunia, and vaginal pH of 5 or greater; and selfreported willingness to be sexually active.The exclusion criteria included use of vaginal moisturizers or lubricants in the last 30 days; vaginal hormonal treatment in the last 6 months; use of radiofrequency, laser treatment, hyaluronic acid, or lipofilling in the vagina in the last 2 years; ospemifene treatment; intraepithelial neoplasm of cervix, vagina, or vulva; active genital tract infection; prior treatment for genital cancer; organ prolapse stage II or greater; and positive test results for human papillomavirus.Recruitment began in October 2020 and finished in September 2021.Ethnicity was self-reported by patients and assessed to describe the cohort.

Sample Size Calculation and Randomization
Considering the FSFI score as the primary outcome, a sample size of 33 women was calculated for each group, accepting an α risk of 0.05 and a β risk of less than 0.1 in a bilateral contrast.The common SD was considered to be 5 points, and the minimum expected effect size was 4 points. 13,14Assuming a loss to follow-up of 15%, the calculated sample size was 78 patients.
Participants were equally assigned by 1:1 block randomization to either CLT or SLT using Stata software version 15.1 (StataCorp).The block sizes were 8. Allocation concealment was performed using a protected personal code folder on the hospital intranet.Access to the randomization folder was limited to an authorized collaborator physician who had no other involvement in the study.

Interventions
At the first visit, patients completed all the questionnaires.Additionally, participants underwent a vaginal examination to evaluate the genital tract and collect samples for analysis.

First-line Therapy
All patients from both groups were instructed to use the FLT, which was supplied to every participant during the study.This therapy included a hormone-free moisturizer containing hyaluronic acid (Cerviron; IntherPharma) to be used every 3 days, a daily external vaginal hormone-free moisturizer (Lubripiu; CumLaude Lab), and a vaginal vibrator (Meditinum; BCNatal) to be used 2 times per week for 5 to 10 minutes each with the help of intimate lubricant (Mucus).A personal calendar was given to each patient in which they recorded every use of the moisturizer, the vaginal vibrator, and each sexual relation practiced.Additionally, specialized sexual assessment was also offered as an optional visit based on the PLISSIT (Permission, Limited Information, Specific Suggestions, and Intensive Therapy) model. 15

Preparation for the Procedure
The patients were scheduled between 4 to 6 weeks after the first visit.They were instructed to avoid intercourse and use an internal vaginal ovule moisturizer daily 5 days prior and 5 days after the laser session and use topic lidocaine cream 1 hour before the laser session.

Laser Treatment
All patients underwent 5 sessions 1 month apart from the vaginal laser treatment.The treatment was performed by a professional blinded to the treatment group.

All patients reporting symptoms suspicious of vulvovaginal candidiasis or urinary tract infection
prior to the laser session were treated accordingly.Sessions were rescheduled until treatment was completed.
The first step of the procedure involved removal of the external anesthetic cream with a dry gauze.Then, using an exploration speculum, a new dry gauze was inserted into the vaginal canal to remove all residual vaginal moisture.Next, the laser probe was inserted into the vagina without lubrication.A 360°laser probe was used as the first option, but when the diameter was too large, a 90°probe was used.The laser pulses were delivered to treat the entire circumference and length of the vagina from the apex to the introitus.Patients had no visual stimuli since opaque glasses were used; neither was there olfactory stimulus from smoke plume due to the use of an aspirator during the procedure.Auditory stimuli from the laser and aspirator were set to be equal between groups.

Masking
The laser parameters were manually entered by an assistant, and the gynecologist and participants were masked.Only the assistant had access to the randomization folder.Participants could not guess in which group they were allocated, as they were informed that the laser treatments might not produce any discomfort.

Outcomes
Outcomes were assessed on the first visit prior to the initiation of any treatment and 6 months later (ie, 1 month after the fifth laser session).The primary outcome was sexual function, measured using the FSFI.Secondary outcomes included both objective and subjective measures.

Primary Outcome
The FSFI is a generic sexual questionnaire that has been validated for survivors of cancer. 15,16It assesses 6 sexual dimensions (desire, arousal, lubrication, orgasm, satisfaction, and pain).Global sexual function results in a score ranging from 2 to 36 points, with a higher score indicating better sexual function.A cutoff 26.55 points or lower identifies women at risk of female sexual dysfunction. 17,18bjective Secondary Outcomes Dyspareunia | The intensity of dyspareunia was assessed in all patients (sexually active and inactive) at the baseline visit according to their last vaginal sexual activities.Patients were asked to complete a VAS ranging from 0 to 10, with higher score indicating worse dyspareunia.
Body Image | Body image was assessed using the Spanish Body Image Scale (S-BIS), a Spanishlanguage validated questionnaire assessing affective, behavioral, and cognitive body image dimensions in 10 items.The total score is the sum of all the items (range, 0-30), with higher scores indicating more concern regarding body image. 19ality of Life | Quality of life was measured using the Short-Form 12 (SF-12) test, which consists of a total of 12 items in 8 subdimensions on physical functioning.Scores range from 0 to 100, with higher scores indicating better quality of life.20 Vaginal Health Index | The VHI subjectively assesses the elasticity of the vagina, the amount of discharge, the integrity of the epithelium, and humidity, along with pH as the only objective criteria.
The results range from 5 to 21, and scores of 15 or lower indicate vulvovaginal atrophy. 21

Objective Secondary Outcomes
Vaginal pH | To assess vaginal pH, a piece of litmus paper is placed on the lateral vaginal wall until moistened.A pH of 4.6 or higher indicates vaginal atrophy. 22ginal Maturation Index | Cytological samples were collected to assess Vaginal Maturation Index and were assessed by gynecological cytologists blinded to the randomization group and sample sequence (before or after treatment).The relative proportion of parabasal, intermediate, and superficial vaginal epithelial cells was assessed.23 Vaginal Maturation Index scores range from 5 to 25, with higher scores indicating better vaginal health status.
Vaginal Epithelium Thickness | To assesses vaginal epithelium thickness (VET), 2 full-thickness vaginal mucosal samples taken from the right vaginal wall 2 to 3 cm above the introitus were obtained using Tischler biopsy forceps after local lidocaine infiltration.One of the specimens was fixed in formalin and routinely embedded in paraffin for histological evaluation, and 4-μm sections were stained with hematoxylin and eosin and digitized using a IntelliSite Ultra-Fast Scanner (Philips).The slides were evaluated and measured by a gynecologic pathologist.VET was microscopically Vaginal Epithelium Elasticity | The second biopsy sample was used for evaluation of vaginal epithelium elasticity (VEE).VEE measurements were conducted using a customized Atomic Force Microscope (TE2000) equipped with a V-shape cantilever (0.13 N/m) ending with a polystyrene bead spherically shaped with a radius of 4.5 μm (Novascan).Micromechanics were examined by indenting the sample with the bead while recording the force applied, as described in Alcaraz et al. 24 The biophysics investigators were blinded to the randomization group and sample sequence.
Adverse Effects and Tolerance | Immediate adverse effects (AEs), such as bleeding or laceration, were evaluated after every laser session.Late AEs, such as vaginal itching or urinary tract infections, were evaluated in later visits.All AEs were recorded and graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. 25Tolerance to the intervention was assessed using a Likert scale, with scores ranging from 1 to 5, with higher scores indicating more tolerability.

Statistical Analysis
Statistical analyses were performed with Stata software version 15.1 in July 2022.Normal distribution of the sample was evaluated using the Shapiro-Wilk test.Analyses of the main outcome (FSFI) and secondary outcomes were performed.Continuous variables were compared using the independent or paired-samples t test and presented as mean and SD.Contingency tables were assessed using the Fisher exact test.A 2-sided P < .05 was considered statistically significant.

Results
A total of 211 women who had been treated for breast cancer were assessed for eligibility.Of these, 84 women were randomized into the 2 treatment groups and 72 participants (mean [SD] age, 52.3 shown in Table 1.No differences in any of the parameters were observed between groups.

Overall Outcomes Before and After Treatment
Table 2 shows the overall outcomes before and after treatment of all the patients included in the study.All 72 patients used the FLT, and the mean (SD) use of vaginal ovules was 9.5 (X.X) per month.
The mean (SD) use of the vibrator was 5.6 (X.X) times per month.The mean (SD) monthly frequency of sexual activity was 2.7 (X.X) events.There was significant improvement in all the subjective and objective parameters at the 6-month follow-up, except in quality of life and VET.

Primary Outcome
There was improvement of the primary sexual function after treatment evaluated through the FSFI test in the overall analysis, regardless of group.Overall, FSFI improved from a mean (SD) of 15.2 (7.2) points at baseline to 21.8 (8.1) points at the 6-month follow-up (P < .001).Excluding women who were not sexually active did not change the results (mean [SD] score: baseline, 18.9 [5.2]   f Range, 0 to 100; higher scores indicate better quality of life.

Secondary Outcomes After Treatment by Randomized Groups
Results of the secondary outcomes evaluated before and after treatment in the 2 groups are shown in Table 3 and the eFigure in Supplement 2. None of the parameters evaluated showed statistically significant differences between groups in changes at the 6-month follow-up, including dyspareunia (mean [SD] difference, −4.3 [3.4]

Tolerance and Safety
The mean (SD) tolerance score was 3.3 (1.3) in the CLT group and 4.1 (1.0) in the SLT group (P = .007).
Complications related and not related to the use of vaginal laser therapy were also recorded, and no differences were identified between groups.Serum estradiol levels were assessed to ensure the safety of the laser in survivors of breast cancer, and no increase from menopausal levels was observed in the CLT group before vs after treatment (mean [SD], 3.1 [5.1] pg/mL vs 3.5 [2.4] pg/mL; P = .27).The tolerance and safety of the treatment and the differences between groups are shown in Table 4.

Figure
Figure.Participant Flowchart

[ 8 . 3 ]
years) were analyzed, including 35 patients randomized to CLT and 37 patients randomized to SLT.The Figure shows the flowchart of the patients initially recruited in each arm and the women excluded with details of exclusion criteria.The demographic characteristics of the 2 study groups are

Table 1 .
Demographic Characteristics of the Two Study Groups Abbreviation: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared).

Table 3 .
Efficacy Outcomes Before and After Treatments by Group a P values are the mean differences in the variable values of the 2 groups after treatment, assessed with t test.bRange, 2 to 36 points; lower scores indicate worse sexual dysfunction.cAssessed with a visual analog scale ranging from 0 to 10, with higher score indicating worse dyspareunia.dRange, 5 to 21; scores of 15 or lower indicate vulvovaginal atrophy.eRange, 0 to 30; higher scores indicate more concern regarding body image.

Table 4 .
Tolerance and Safety Assessment Values of the Two Study Groups a Assessed with t test.bTolerance to the intervention was assessed using a Likert scale, with scores ranging from 1 to 5, and with higher scores indicating more tolerability.c Shown in a CTCAE (Common Terminology Criteria for Adverse Events) scale.d Assessed with Fisher exact test.