OBG Management: When colposcopy is used, is the procedure the same as for cervical examination?
Dr. Massad: Not exactly. The clinician should apply 5% acetic acid for 5 minutes using a gauze sponge, but the magnification should be 63 to 103—not 153, as it is for cervical examination. It’s important to distinguish hyperplasia from VIN. In general, hyperplastic lesions are faint, gray, diffuse, and flat, whereas VIN lesions are raised and irregular in shape, with sharp borders.
OBG Management: What about toluidine blue? Is it useful in inspection of lesions?
Dr. Massad: Toluidine blue stains skin that is irritated. It isn’t very specific for VIN or vulvar cancer, and it can make colposcopy difficult, so experts no longer recommend it.
OBG Management: What are the treatment options for VIN?
Dr. Massad: They include surgical excision, laser ablation, and topical therapy with 5% imiquimod. All are potentially effective. The Committee Opinion doesn’t specify a preference, except to say that excision is advised when there is any suspicion of cancer to preserve a sample for pathologic analysis. Ablation destroys the lesion, making assessment of possible invasion impossible, and imiquimod may allow disease to progress during observation.
OBG Management: The Committee Opinion recommends wide local excision when cancer is suspected. What size of margin is optimal?
Dr. Massad: In general, a margin of 5 to 10 mm around the lesion is recommended. Vulvectomy isn’t needed because close follow-up usually identifies recurrence before invasion occurs.
OBG Management: When is laser ablation a good choice?
Dr. Massad: Whenever a biopsy shows VIN and cancer is not suspected. Laser ablation is ideal when lesions are multifocal or extensive, although repeated treatments may be required to resolve small foci of residual disease. Done with careful attention to power density and depth of ablation, laser therapy can be less disfiguring than excision.
OBG Management: You mentioned 5% imiquimod. Is there evidence that it’s effective in the treatment of VIN?
Dr. Massad: Multiple randomized, controlled trials have shown 5% imiquimod to be effective against VIN, although the agent does not have approval from the FDA for that indication.5,6 Lower concentrations of imiquimod have not been studied in the treatment of VIN. Women treated with this topical therapy should be followed every 4 weeks with colposcopy because progression to cancer has been reported during imiquimod therapy. Lesions that fail to respond completely after a full course of imiquimod should be treated with excision or laser ablation.
Surveillance is critical
OBG Management: According to the Committee Opinion, the recurrence rate of VIN can reach 30% to 50%.7 Why so high?
Dr. Massad: Usual-type VIN reflects exposure to carcinogenic HPV, and differentiated VIN arises from a vulvar dystrophy. In both situations, treatments destroy VIN and arrest progress to cancer, but the entire vulvar skin remains subject to the inciting condition.
OBG Management: Would skinning vulvectomy eliminate the risk of recurrence?
Dr. Massad: Full vulvectomy is crippling and usually unnecessary. Most patients and clinicians accept the risk of recurrence of VIN to avoid the side effects of radical treatment.
OBG Management: What kind of surveillance is recommended after treatment?
Dr. Massad: Patients should perform vulvar self-examination every few months. They should also be examined 6 and 12 months after initial treatment and annually thereafter because the risk of recurrence may persist for years.
Because VIN is associated with carcinogenic HPV, women with VIN should undergo an annual Pap test.
OBG Management: Thank you, Dr. Massad. Let’s hope the incidence of this precancer begins to decline.
- Recommend the quadrivalent HPV vaccine for girls in the target age range (11 and 12 years old) to reduce the risk of VIN.
- Encourage smoking cessation.
- Make it a practice to inspect the vulva before inserting the speculum for cervical examination.
- Biopsy most pigmented lesions on the vulva. Biopsy all warty lesions in postmenopausal women and in women who fail topical treatment for genital warts.
- Treat all VIN lesions. When cancer is suspected, use wide local excision with a margin of 5 to 10 mm.
- Keep in mind that dysplastic cells can extend into hair follicles and sweat glands.
- Closely follow up all women treated for VIN (6 and 12 months after treatment and annually thereafter) and encourage them to examine their vulva several times every year. Perform an annual Pap test for any woman found to have VIN.
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