Past cervical intraepithelial neoplasia grade 3, obesity, and earlier menopause are associated with an increased risk of vulval cancer in postmenopausal women.

Vulval cancer predominantly affects postmenopausal women. A smaller proportion of vulval cancers, particularly at older ages, are now thought to be associated with human papillomavirus infection than previously reported, but other risk factors have not been well examined in prospective cohort studies.

A total of 1.3 million women aged 49-65 years were followed for incident vulval cancer (ICD-10 C51). Adjusted Cox regression models were used to examine the relationship between reproductive and lifestyle factors and risk of vulval cancer.

There were 898 vulval cancers registered in the cohort over an average of 14 years of follow-up; 70% were squamous cell carcinomas. Past registration of cervical carcinoma in situ (RR 2.68; 95% CI 1.71-4.18; P<0.001), obesity (RR 1.71; 95% CI 1.44-2.04; P<0.0001), and menopause before the age of 50 years (RR 1.52; 95% CI 1.22-1.89; P<0.001) were associated with a significantly increased risk of subsequent vulval cancer.

Past cervical pre-cancer, obesity, and earlier age at menopause are associated with an increased risk of vulval cancer at older ages.