Chapter 9: Vulvar Cancer

INTRODUCTION

Vulvar cancers are among the least common gynecologic malignancies. Radical surgery is the primary approach for most patients, and advances in neoadjuvant chemotherapy and radiation may decrease operative morbidity in those patients with locally advanced disease. This chapter focuses on the diagnosis and management of vulvar cancer, with special emphasis on changes in staging and sentinel lymph node biopsy (SLNB). Due to the recent modifications in International Federation of Gynecology and Obstetrics (FIGO) staging, the reported outcomes in this chapter reflect the older staging criteria.

EPIDEMIOLOGY

Key Points

1. Vulvar cancer is the fourth most common gynecologic malignancy, with approximately 3900 diagnoses in 2010.

2. Prevention strategies for cervical dysplasia using the human papillomavirus (HPV) vaccine may decrease the incidence of vulvar dysplasia and vulvar carcinoma.

3. The median age of patients with vulvar cancer is 68 years of age, with approximately 1 in 387 women at risk for a vulvar cancer diagnosis during their lifetime.

4. Risk factors for invasive vulvar cancer depend on age of diagnosis and may include HPV infection, smoking, immunosuppression, and potentially lichen sclerosis.

Vulvar cancer is the fourth most common gynecologic malignancy in the United States, with approximately 3900 diagnoses in 2010.¹ The incidence of this disease increases with age and peaks in the seventh decade of life. The majority of vulvar cancers are of squamous histology, and many develop from progressively worsening dysplastic conditions known as vulvar intraepithelial neoplasia (VIN).

In the United States, the demographic characteristics of the 12 areas associated with the Surveillance, Epidemiology, and End Results (SEER) study demonstrate that the median age for patients with a diagnosis of vulvar cancer is 68 years.² Only 26.6% of patients have a diagnosis at age younger than 55 years, with most women being in their 60s and 70s at diagnosis.² Recently, Kumar and colleagues³ observed that approximately 19% of women who have a diagnosis of vulvar cancer are younger than 50 years. These women appear to have an overall better prognosis because their tumors are characterized by lower stage and superficial invasion.

Vulvar cancer may arise through 2 distinct pathways, each with its respective risk factors. The first is characterized by nonkeratinizing carcinomas and is more commonly diagnosed in younger women with VIN and concurrent HPV infection. The second pathway results in keratinizing, well-differentiated carcinomas; these are more frequently diagnosed in older women with a background of vulvar dystrophies such as lichen sclerosus. HPV infection is rarely identified in these women.

HPV infection remains a significant risk factor for the development of vulvar dysplasia and subsequent malignant transformation in the first type of invasive vulvar carcinoma.⁴ Recent advances in immunization may decrease the incidence of VIN and vulvar cancer through prevention of HPV infection. A recent 4-year trial has demonstrated the benefit of the prophylactic HPV quadrivalent ...