ACOG Committee Urges Treatment for All Cases of VIN

The American College of Obstetricians and Gynecologists released a new committee opinion urging clinicians to treat all patients presenting with vulvar intraepithelial neoplasia (VIN). The opinion is a result of an increasing incidence of VIN, particularly among US women in their 40s. The full opinion was published in the November issue of Obstetrics & Gynecology.

According to data from the US Surveillance, Epidemiology, and End Results program, the incidence of VIN increased more than fourfold between 1973 and 2000. While some VIN cases may result in spontaneous regression, research indicates that VIN should be considered a premalignant condition.

VIN is divided into two subtypes: usual-type VIN and differentiated VIN. While differentiated VIN is usually linked to dermatologic conditions of the vulva, usual-type VIN is associated with the cancer-causing strains of human papillomavirus (HPV). Studies have shown that quadrivalent HPV vaccine can reduce the risk of VIN; as such, it is recommended for target populations. However, ACOG committee opinion authors noted that the bivalent vaccine does not have such an indication. Risk factors for usual-type VIN also include smoking and compromised immune systems. While smoking cessation is encouraged, there is no data showing cessation will lead to decreased incidence of VIN.

Currently, there is no screening recommendation for preventing vulvar cancer. Since diagnosis is obtained via visual assessment, the committee noted that biopsy should be considered for most pigmented vulvar lesions. Furthermore, the committee recommends that all presumed genital warts should be biopsied in postmenopausal women as well as in women for which previous topical treatments have failed.

The committee further noted that all patients should receive treatment for all cases of VIN. The committee noted that the risk of cancer progression outweighs the risk of treatment. When cancer is suspected, wide local excision is recommended by the committee; this, they noted, will help to identify occult invasion. The excision should be tailored to the lesion to achieve optimal outcomes.

In those cases where occult invasion is not a concern, the committee advised that the VIN can be treated with excision/surgical therapy, laser ablation, or topical imiquimod (off-label use). When using laser ablation, clinicians should aim to effect full-thickness epithelial destruction. Laser ablation can be used for single, multifocal, or confluent lesions. However, the committee cautions that the risk for recurrence may be higher in patients treated with ablation as compared to their surgically treated counterparts.

Since posttreatment recurrence rates are high across treatment options, the committee recommends that clinicians monitor women at the 6 month and the 12 month follow-up visits. “Because the recurrence rate exceeds 30-50%, women diagnosed with VIN must be vigilant and report any vulvar changes to their gynecologist,” Dr Gerald F. Joseph, Jr, vice president for Practice Activities for the American Congress of Obstetricians and Gynecologists, said in a statement to the press. However, VIN usually progresses slowly, so women who successfully completed treatment and did not present with any additional lesions at the 6 month and 12 month marks can move to annual evaluations.

Reference:

The Committee on Gynecologic Practice of the American College of Obstetricians and Gynecologists and the American Society for Colposcopy and Cervical Pathology. Management of

Vulvar Intraepithelial Neoplasia. 2011; 118(5):1192-1194.
ACOG. Vulvar precancer cases increase more than fourfold. Press Statement. October 20, 2011.