Squamous cell carcinoma of the anal canal: a review of the aetiology, presentation, staging, prognosis and methods available for treatment

Anal cancer is an uncommon malignancy, with the majority of cases comprised of squamous cell carcinomas. The increasing incidence of this disease reflects a rise in the transmission of the human papillomavirus, the causative organism of most tumours. Abdominoperineal resection (APR), once the primary mode of treatment, has been supplanted by sphincter-saving combination chemoradiation as the first-line therapy. However, surgeons continue to play a role in the multidisciplinary management of patients with anal cancer for diagnosis and post-treatment surveillance. Sentinel node biopsy may identify patients with clinically and radiographically negative inguinal lymph nodes who will benefit from groin irradiation. In very select cases, the controversial means of local excision has been employed as primary treatment, often in conjunction with radiation and chemotherapy. The management of persistent or recurrent anal cancers following primary chemoradiation remains a concern, for which only salvage APR currently offers the possibility of a cure. The introduction of human papillomavirus vaccines presents the exciting potential for the eradication of the disease.