Diagnosis and management of anal intraepithelial neoplasia and anal cancer.

#### Summary points Anal cancer accounts for about 4% of large bowel malignancies, but data from the Surveillance Epidemiology and End Results programme show a considerable rise in incidence since 19751 from 0.8 to 1.7 per 100 000. The World Health Organization recently estimated that between 350 and 500 new cases of anal squamous cell carcinoma are detected each year in England and Wales.2 Observational studies have shown that individuals with genital human papillomavirus (HPV) infection and those who are immunosuppressed, including HIV positive patients, are at increased risk of developing anal cancer.3 4 A history of cervical or vulval HPV infection and premalignant changes also increases the risk of developing anal cancer, with a reported incidence rate ratio of between 3.97 and 31.09, dependent on age at diagnosis, compared with controls.5 General practitioners and practice nurses who screen women as part of national programmes for detecting cervical malignancy should be aware of the association between HPV infection and anal cancer. The majority of anal …