HOUSTON — Whether to treat genital warts would seem like a no-brainer, but Peter J. Lynch, M.D., has a list of reasons for not trying to eradicate some vulvar lesions.
Many genital warts resolve spontaneously. The underlying cause, human papillomavirus (HPV), is so widespread that it's “nearly universal.” Moreover, destroying the lesion will not eradicate latent virus in the host, he said at a conference on vulvovaginal diseases sponsored by Baylor College of Medicine.
“There's a high rate of recurrence with all forms of treatment and a high cost for treatment, both economically and psychologically, with very little benefit,” concluded Dr. Lynch, a dermatologist in Sacramento.
Having said all that, he included himself among the majority of clinicians who treat genital warts. Patient wishes, concerns about cancer risks, and legal vulnerability make genital warts difficult to ignore, he said.
Vulvar warts must be characterized and the source of infection confirmed before they are treated. Vulvar HPV lesions are highly variable, and the most common forms are:
▸ Filiform warts (condyloma acuminata) are taller than they are wide. They are about a quarter-inch to a half an inch long and skin colored or slightly pink. The tip is a little thicker than the stalk and often consists of brush-like bristles.
▸ Papules or nodules are as wide as they are tall—usually about the size of a pencil eraser (but sometimes as large as a plum), and skin colored or light brown. These are usually smooth but can feel rough if they occur in dry anogenital tissue.
▸ Flat warts are small, bare-topped, barely elevated papules that are wider than they are tall. They are about a quarter-inch in diameter and skin colored, pink, tan, or dark brown. The most common type of wart in the vulva, flat warts can coalesce into flat-topped plaques.
Dr. Lynch recommended biopsy to make certain the cause is HPV infection and to rule out malignancy, especially in flat warts, which are the most likely to show dysplasia. More than 90% of vulvar HPV infections are caused by low-risk forms of the virus.
High-risk types such as HPV 16 and HPV 18 occur in 5%-8% of vulvar HPV infections. Although these can lead to malignancy, he characterized the transition as very slow, with ample time for curative therapy.
Once vulvar HPV infection is established, other anogenital areas should be examined to rule out possible HPV infection there, as well. The next step, he said, is to choose among the following three therapeutic options:
▸ Home-based medical therapy in which the patient applies a 5% cream of imiquimod (Aldara) or podofilox (Condylox). Dr. Lynch estimated about a third of patients will have complete clearance after 2 months of such treatment.
▸ Office-based medical therapy allows the clinician to monitor compliance. Dr. Lynch characterized this choice as inconvenient for patient and clinician, and the response rate is similar to home-based treatment.
▸ Office-based destructive treatments can be quite effective. Electrosurgery, excision, laser therapy (all requiring anesthesia) can have a 100% response rate, while cryotherapy, podophyllin, tri- or bichloracetic acid, and 5-fluorouracil (without anesthesia) will lead to complete clearance in two-thirds of patients.
“Unfortunately, there are no criteria to choose one [treatment] over the other. It is disturbing how little we have, except for anecdotal data,” Dr. Lynch said.
His recommendation: Use home therapy or go to destructive therapy and expect at least a 35% recurrence rate with either approach. A caveat: Dr. Lynch said vulvar warts should be treated in pregnant women, but warned that podophyllin and its derivatives should not be used.