SEOM clinical guidelines for the treatment of anal cancer.

Anal carcinoma is an uncommon disorder accounting for less than 2% of large bowel malignancies and 1-6% of anorectal tumours. Its incidence ranges between 0.5 and 1% per 100,000. Local staging should be done with MR imaging using an external pelvic phased-array coil. Treatment strategy should be optimally discussed in a multidisciplinary team. HIV-positive patients seem to achieve similar response rate and overall survival to HIV-negative patients but with increased toxicity and higher local recurrences. Combined modality treatment with irradiation and chemotherapy has resulted in complete response over 90% and local control over 85%. This guide gives recommendations for diagnosis, staging and treatment.