Objective: To evaluate the natural history of vaginal intraepithelial neoplasia (VAIN) and to identify risk factors for invasive vaginal carcinoma.
Methods: The records of all women with VAIN diagnosed at military treatment facilities over a 10-year period with minimum follow-up of 12 months were reviewed. Patient demographics and clinical information related to the diagnosis and treatment of VAIN were recorded.
Results: One hundred twenty-seven women with VAIN met inclusion criteria. The mean age was 47.4 years, and median surveillance was 34 months (range 12-169 months). Seventy-five patients had low-grade vaginal dysplasia as their initial diagnosis, and 15 (20%) of these patients underwent treatment. Fifty-two patients had high-grade vaginal dysplasia, of which 38 (73%) underwent treatment. Overall, 113 patients (89%) demonstrated normalization of disease, 11 patients (9%) demonstrated persistence of disease, and three patients (2%) experienced recurrence of disease. No patients experienced development of invasive vaginal carcinoma. However, median time to normalization was 6 months longer in patients with low-grade dysplasia compared with those with high-grade dysplasia (15.9 months compared with 10.0 months; hazard ratio 1.5; 95% confidence interval 1.004-2.1; P=.045). Patients with high-grade dysplasia had more biopsies performed during their surveillance than patients with low-grade dysplasia (3.3 compared with 2.5; P=.045).
Conclusion: Overall, 89% of patients demonstrated normalization of VAIN, and none had progression to invasive cancer. Normalization, persistence, and recurrence rates did not significantly differ by grade of dysplasia or treatment status. Based on our findings regarding the time to normalization, annual surveillance with combined cytology and colposcopy is likely adequate. Because 11% of patients with VAIN either will experience recurrence or will have persistent disease, lifetime surveillance is recommended.
Level of evidence: : III.