UK Vulva Cancer incidence statistics

The vulva site includes the labia majora, labia minora and the clitoris ( Figure 1.1).

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Cancer of the vulva is rare and, when coupled with cancer of the vagina, accounts for less than 1% of all cancer cases (excluding non-melanoma skin cancer) and 7% of gynaecological (ovarian, uterine, cervical, vaginal and vulval) cancers diagnosed in women in the UK.

It has been estimated that the lifetime risk of developing vulval cancer is 1 in 316 for women in the UK. These were calculated on February 2009 using incidence and mortality data for 2001-2005 24.

In 2006, 1,063 new cases of vulval cancer were diagnosed.( Table 1.1). 1-4 The European age-standardised incidence rate of vulval cancer in the UK is around 2 per 100,000 female population. 1-4

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Vulval cancer is very rare in young women aged under 25. Rates are around 1 per 100,000 among women aged 25-44, rising to around 3 per 100,000 in those aged 45-64, and peak at 13.2 per 100,000 in women aged 65 and over ( Figure 1.2). 1-4

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While there were slight falls in the incidence of vulval cancer between 1975 and the mid-1980s, increases since the mid-1990s mean that incidence has now reached a similar level to that of 1975 ( Figure 1.3). 1-4

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There has been a significant increase in rates of vulval cancer in younger women. The proportion of cases diagnosed under the age of 50 rose from 6% in 1975 to 15% in 2006. 1-4A similar trend has been documented in other countries, 5, 6 and has been linked to increasing incidence of vulval intraepithelial neoplasia (VIN) in young women caused by infection with HPV. 6

Figure 1.4 shows the vulval cancer incidence trend for the UK.

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It is estimated that almost 27,000 women worldwide are diagnosed with vulval cancer each year. 7

Rates range from less than 0.3 per 100,000 females in parts of Asia to about 1.6 per 100,000 females in north America and Europe ( Figure 1.5). 7 This variation is probably related to differing prevalence of HPV infection in world regions, and other lifestyle factors, especially smoking, and their interaction with HPV (see Risk factors).

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Several case-control studies have reported an increased risk of vulval cancer associated with lower socio-economic status and fewer years of education. 8-14

Squamous cell carcinomas (SCC) account for more than 90% of vulval cancers. 15 The other 10% includes melanomas, sarcomas, basal cell carcinomas and adenocarcinomas. 16

A substantial proportion of vulval invasive tumours are found with adjacent evidence of pre-cancers, known collectively as vulval intraepithelial neoplasia (VIN).

There are two main types of VIN. HPV-related, which precedes almost all vulval cancers in women under 45, and lichen sclerosus-related, the major cause of vulval cancer in older women. 17, 18

The classification system for VIN changed in 2004 to better reflect the two divergent types of lesions ( Table 1.2). 19, 20

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Annual risk of invasive vulval cancer in women with untreated carcinoma in situ (high-grade VIN) of the vulva is at least 10%, while risk of progression in treated lesions over a period of years is between 2% and 5%. 21 The absolute risk for women treated for lichen sclerosus is at the top end of this range, 20 and relative risks greater than 300 have been reported for vulval SCC in women who have undergone treatment. 22, 23