Methods
The patients with biopsy-proven VaIN were recruited in the study from April 2016 to April 2021, and followed-up until October 2021 in the gynecological out-patient department at Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology in China. The patients were eligible for inclusion if the following criteria were fulfilled: more than two pathologists diagnosed the biopsy of the vagina as VaIN; and the patients accepted MTLA procedures and were compliant with regular follow-up. The exclusion criteria were as follows: 1. patients suspicious of malignant tumors of the lower anogenital tract; 2. patients suffering unhealing malignant tumors of other systems; 3. patients received radical hysterectomy with after-loading radiotherapy; 4. patients with insufficient exposure of VaIN lesions; and 5. pregnant women. Those patients diagnosed with LSIL(VaIN1) should suffer at least one of the following risk factors: the cytologic test suggesting HSIL, persistent HR-HPV infection, concomitant or previous diseases of cervical or vulvar intraepithelial neoplasia (VIN), multifocal lesions, large areas of lesions, immunosuppression and so on. Immunosuppression was defined as suffering the situations of autoimmune diseases, history of chemotherapy and/or radiotherapy for cancers, using immunosuppressing drugs after organ transplants and so on. Suitable subjects were enrolled in the study with written informed content. This study was approved by the Institutional Review Board at Tongji Hospital (TJ-IRB20210134) and registered at ClinicalTrials.gov (NCT05170620).
All subjects were tested for cytology mostly with Thin-prep (Hologic Inc, USA) and tested HPV-DNA mostly with Cervista (Hologic Inc, USA) or Cobas 4800 (Roche Group, Switzerland). The colposcopic examinations were completed with Leisgang colposcope (3ML, Germany). The terminology and interpretation of colposcopy was implemented according to the 2017 criteria of the International Federation of Cervical Pathology and Colposcopy (IFCPC). Laser ablation was performed with a CO2 laser treatment machine (IC25, Yuhua Medical Instruments Company in China).
The laser treatment for VaIN in the study was named multiple targeting laser ablation (MTLA) including therapeutic laser ablation (TLA) and strengthened laser ablation (SLA). All patients received colposcopic examinations before initial treatment by the same gynecologist with more than ten years’ experience to locate the lesions. The procedure of laser ablation required targeting at the lesions in continuous mode, energy 10~20W, vaporizing 1~2mm deep and outside 3~5mm of the lesions’ margins. TLA was defined as MTLA with the intervals of 1~6 months until pathological regression and HR-HPV clearance. SLA was then arranged for some patients with high-risk factors of relapse with 1~2 number of laser ablation. The intervals between MTLA were decided according to the wound healing state. The contents of surveillance in therapeutic phase included cytologic tests, HR-HPV tests, colposcopic examinations and biopsies if necessary, every 3~6 months. If suspicious VaIN lesions were found by colposcopy or pathological examinations, repeat laser ablation was preferred. But for a few patients suspicious of invasive lesions, surgical excisions were performed. After accomplishing the treatment, the patients were followed-up every 6 months in 2 years, then every 3 years after three consecutive normal results.
The primary outcome measure was the pathological cure. Pathological cure meant no VaIN found by colposcopy and biopsy. The secondary outcome measure was HR-HPV negative rate. Data were collected including age, menopause status, gravidity, parity, contraceptive methods, history of past illness, cytologic and HR-HPV tests, colposcopic examinations, areas of VaIN lesions, pathological examinations, parameters of laser ablation and so on.
Meta-analysis of relevant studies was also carried out through a search of PubMed, Cochrane Library, Web of Science, Wanfang, China Science and Technology Journal Database, China National Knowledge Infrastructure with the key words of “laser” and “vaginal intraepithelial neoplasia”. The last time of searching was August 24th, 2021. Researches published in English or Chinese were included in the meta-analysis. The screening process was accessed by two independent researchers. Researches with samples of laser ablation for VaIN more than 15 cases from 2000 to date were included, and efficacy and 95% confidence interval (CI) were calculated.
The data of the study were calculated and analyzed by SPSS version 27. Univariate analysis was performed by bivariate correlation analysis, and multivariate analysis was performed by multivariate logistic regression analysis with two-sided P<0.05 as statistically different. Meta-analysis was performed by Stata 15SE. Heterogeneity was assessed by Q statistical test with P<0.1 as statistically different. According to the heterogeneity between studies, the random effect model was used to calculate and combine the laser ablation efficacy.