Dr. Stephanie A. Sullivan
Diagnosis is ultimately made by biopsy. Physicians should have a low threshold to biopsy any suspicious lesions or those unresponsive to therapy. Colposcopy is a frequent adjunct to the physical exam. Acetic acid 3%-5% soaked gauze is allowed to rest on the vulva for several minutes prior to observation with a colposcope or hand-held magnifying glass. Colposcopic findings are usually those of focal “white” epithelium. Vascular changes seen on the cervix (punctuation and mosaicism) are rarely seen on the vulva.
The entire anogenital region shares the same susceptibility to the HPV virus, thus squamous intraepithelial lesions are frequently multifocal. Physicians should have a heightened awareness of other lesions, such as cervical, vaginal, or anal, when managing a patient with VIN (Gynecol Oncol. 1995 Feb;56[2]:276-9). Appropriate cervical screening should be strictly adhered to and a thorough exam done at the time of vulvar colposcopy or exam.
Treatment
The goals of treatment include preventing carcinoma and improving symptoms while maintaining function and preserving anatomy. Treatment options for both types of VIN include excision, ablation, or medical therapy pending an evaluation of concurrent risk factors.
Premalignant disease was traditionally treated surgically. While surgical excision is still the mainstay of therapy, less aggressive techniques and medical therapy are more readily utilized. The goal of surgical excision for VIN is both diagnostic and therapeutic. When an excision for high-grade dysplasia is done (formerly VIN 3), detection of occult carcinoma was found in up to 3.2% in one large review (Gynecol Oncol. 2005;97:645-51).
Using a wide local excision to completely remove lesions with a pathologically clear margin reduces a patient’s risk of recurrence for disease compared to those excisions with positive margins (Obstet Gynecol. 1998;92:962-6). It is therefore critical that physicians carefully counsel patients who desire conservative therapy for VIN.
With any treatment, however, patients and physicians should be aware of the risk of recurrence; for vulvectomy, partial vulvectomy, local excision, and laser ablation, recurrences were seen at rates of 19%, 18%, 22%, and 23%, respectively, in a review of 3,322 patients (Gynecol Oncol. 2005;97:645-51).
CO2 laser ablation has been used for single lesions as well as multifocal or confluent disease. Many physicians advocate for its use in patients with multifocal lesions as well as those with disease around the clitoris or anus, where excisional therapy is less desirable as laser therapy results in less scarring.
A 2015 Cochrane Database Review of medical therapy for high-grade dysplasia (usual-type VIN, VIN 2/3, or high-grade VIN) found that topical imiquimod can be used as a safe and effective option for high-grade VIN. Physicians should, however, be aware of unfavorable side effects that may require dose reductions. Cidofovir may be an alternative to imiquimod pending more evidence on long-term response and progression (Cochrane Database Syst Rev. 2015 Aug 18;8:CD007924). Topical 5-fluorouracil has fallen out of favor for VIN given its significant chemical desquamation, however response rates are thought to be favorable if tolerated.
As the use of VIN terminology solidifies and information emerges on medical therapy to treat VIN, it is critical that physicians remain current when counseling and providing treatment recommendations for vulvar intraepithelial neoplasia.
Dr. Gehrig is professor and director of gynecologic oncology at the University of North Carolina at Chapel Hill. Dr. Clarke-Pearson is the chair and the Robert A. Ross Distinguished Professor of Obstetrics and Gynecology and professor in the division of gynecologic oncology at the university. Dr. Sullivan is a fellow in the division of gynecologic oncology at the university. They reported having no relevant financial disclosures. Email them at obnews@frontlinemedcom.com.