Clinical outcomes and risk of recurrence among patients with vaginal intraepithelial neoplasia: a comprehensive analysis of 576 cases.

Objective: To evaluate the clinical outcomes of vaginal intraepithelial neoplasia (VAIN) and to assess the risk of recurrence and progression to invasive vaginal carcinoma.

Methods: A retrospective review of the clinicopathologic data and clinical outcomes was performed on patients who were diagnosed with VAIN at a single center between January 2000 and July 2016. Demographics, treatments, and clinical outcomes were abstracted from medical records.

Results: A total of 576 patients with VAIN1-3 were included in the study analysis. The distribution of VAIN1-3 was as follows: VAIN1 31.1%, VAIN2 45.3%, and VAIN3/carcinoma in situ (CIS) 23.6%. In VAIN1 patients, observation was performed in 29.1% of the cases and 48.8% obtained regression. In VAIN2+ patients, management included observation (3.5%), topical management (6.5%), laser ablation (75.3%), excision (14.1%), and radiotherapy (0.5%) with the following rates of recurrence/progression: 46.2%, 62.5%, 26.4%, 32.7%, and 0%, respectively. Four patients among VAIN3/CIS patients (3.2%) developed invasive vaginal cancer during the follow-up period with a median time to cancer diagnosis of 21.4 months (range, 5.0-44.8 months). On multivariate analysis, high-risk human papillomavirus (HPV) positivity and treatment method were found to be independent risk factors for recurrence and progression (p=0.003 and p=0.001).

Conclusion: Patients with VAIN are at high-risk of recurrence, but the risk of progression to vaginal cancer is relatively low. Laser or excision provides higher regression rate than topical agent or observation, and high-risk HPV positivity is a risk factor for recurrence. Whatever the treatment method is used, however, the high rate of recurrence warrants long-term follow-up surveillance.