The Prognostic Role of the Surgical Margins in Squamous Vulvar Cancer: A Retrospective Australian Study

SIMPLE SUMMARY: Squamous cell carcinoma of the vulva is a rare disease, but cure rates are good if managed appropriately. The need for radical vulvectomy was initially challenged about 40 years ago for lesions 1−2 cm diameter. Since then, there has been progressive acceptance of radical local excision for most unifocal squamous vulvar cancers. Originally, a surgical margin of 3 cm around the primary cancer was considered appropriate. Subsequently, a 1 cm margin was generally accepted, but this has become the subject of recent debate. The aims of this study were to determine survival following conservative vulvar resection, and to determine the clinicopathological predictors associated with vulvar recurrence, focusing on the surgical margin. In multivariable analysis, primary site recurrences were increased in patients with margins < 8 mm, and all vulvar and primary site recurrences in patients with margins < 5 mm. Treatment of close or positive margins decreased the risk of recurrence. ABSTRACT: For the last 30 years at the Royal Hospital for Women, unifocal vulvar squamous cancers have been treated by radical local excision, aiming to achieve a histopathological margin of ≥8 mm, equating to a surgical margin of 1 cm. The need for a margin of this width has recently been challenged. We aimed to determine the long-term outcome following this conservative approach, and the relationship between vulvar recurrences and surgical margins. Data were obtained retrospectively on 345 patients treated primarily with surgery for squamous vulvar cancer between 1987 and 2017. Median follow-up was 93 months. Five-year disease-specific survival was 86%. Of 78 vulvar recurrences, 33 (42.3%) were at the primary site and 45 (57.7%) at a remote site. In multivariable analysis, a margin < 5 mm showed a higher risk of all vulvar (Hazard ratio (HR), 2.29; CI, 1.12−4.70), and primary site recurrences (subdistribution hazard ratio (SHR), 15.20; CI, 5.21−44.26), while those with a margin of 5 to <8 mm had a higher risk of a primary site recurrence (SHR, 8.92; CI, 3.26−24.43), and a lower risk of remote site recurrence. Excision margins < 8 mm treated by re-excision or radiation therapy had a significantly decreased risk of recurrence. Guidelines should continue to recommend a surgical margin of 1 cm.