Vulvar intraepithelial neoplasia III: Occult cancer and the impact of margin status on recurrence

Objective: To determine the impact of margin status on disease recurrence and the incidence of occult cancer in women diagnosed with vulvar intraepithelial neoplasia (VIN) III and treated with surgical excision. Methods: Between 1989 and 1995, 73 women were diagnosed preoperatively with VIN III by vulvar biopsy and were treated with surgical resection. Patients were examined postoperatively, and recurrence was diagnosed when a biopsy of suspicious lesions confirmed VIN III. Results: The mean age was 45 years; 81% of the patients were white, and 18% were black. Eighty-two percent of the women had used tobacco, 56% had prior cervical dysplasia, and 37% had prior genital warts. An underlying squamous vulvar cancer was found in 22% of patients at initial treatment for VIN III. Fifty-nine women had follow-up of at least 7 months. Of these, 66% (39 of 59) had positive surgical margins, 31% (18 of 59) had negative margins and 3% had unknown margins (two of 59). With positive margins, 46% (18 of 39) suffered recurrent disease; with negative margins, only 17% (three of 18) had recurrent disease (P = .03). Multifocal disease and a history of genital warts also correlated with VIN III recurrence (P = .03 for both). Conclusion: A significant number of women diagnosed initially with VIN III on a vulvar biopsy harbored occult vulvar cancer. Recurrences were almost threefold higher when margins were positive for residual VIN III. We conclude that surgical resection is an appropriate method of treatment of VIN III for both diagnostic and therapeutic purposes. (Obstet Gynecol 1998;92:962-6. (C) 1998 by The American College of Obstetricians and Gynecologists.).