Introduction

Vulval cancer is predominantly a disease of older population. In 2014, there were 1289 new cases of vulval cancer in the United Kingdom, accounting for <1% of all cancers. The lifetime risk of developing vulval cancer is 1 in 275 women and age-standardised (AS) rate is 2.5 per 100,000 of female population. Although vulval cancer is rare, it is anticipated that the incidence will rise alongside the increasingly ageing population in the United Kingdom. More than half of all vulval cancers diagnosed in 2014 were in women aged 70 years and above. The incidence of vulval cancer is also rising in the younger population. A retrospective population study in the United Kingdom has identified an upward trend of new cases diagnosed in the 20–69 year age group over the last 20 years.

Survival is dependent on several factors including pathological staging and histological subtype. In the United Kingdom, the mortality due to vulval cancer remained stable over the last 10 years, and overall 5- and 10-year AS survivals for vulval cancer are 63.6% and 52.6%, respectively.

Anatomical Considerations

A good knowledge of the anatomy of vulva is essential to understand the patterns of spread in vulval cancer, and is the basis of the pathological staging using the International Federation of Gynecology and Obstetrics (FIGO) classification (see Appendix) (Figure 13.1).

Arteries – The arterial supply of the vulva is derived from the internal pudendal artery (branch of internal iliac artery) and superficial and deep external pudendal artery (both are branches of femoral artery). As the internal pudendal artery enters the lesser sciatic foramen within the Alcock's canal, it divides into inferior rectal, perineal and bulbar branches, where the latter will go on to supply the crus and glans of the vulva through deep arteries of clitoris and dorsal clitoral artery, respectively.

Veins – Venous drainage is mainly through the internal pudendal vein and deep dorsal vein of clitoris, with additional drainage by the external pudendal vein.

Lymphatic drainage – The lymphatic drainage of the vulva follows the external pudendal blood vessels to the inguinal lymph nodes (superficial and deep), the external iliac nodes and then the common iliac and para-aortic nodes. Midline structures have a higher tendency to drain into lymph nodes bilaterally. There are usually 3–5 deep inguinal lymph nodes.