Key Concepts

• Tumors of the anal region are divided into anal and perianal cancers with different paths of lymphatic drainage.
• Squamous cell carcinoma (SCC) is the most common type of anal cancer.
• Chemoradiotherapy is the mainstay for anal (SCCa). The standard chemotherapy consists of 5-FU and mitomycin. The minimum dose of radiation is 45 Gy to the primary tumor.
• Inguinal node metastasis can be diagnosed with PET-CT and managed with radiation.
• Surgery for anal canal cancer is limited to very small lesions and salvage situations following failed chemoradiotherapy.
• Anal adenocarcinoma can arise from an anal gland or chronic fistula tract. They can be difficult to distinguish from distal rectal cancers. These tumors are staged and treated similar to rectal cancers with a lower overall survival.
• Verrucous carcinomas are characterized by large size and lack of invasion. Treatment is mainly wide surgical excision.
• Anal melanoma is a rare and aggressive tumor. Survival is very poor. Abdominoperineal resection may help to control local disease but does not prolong life expectancy; therefore, local excision is often a first choice when possible.
• Perianal Paget’s disease – or intraepithelial adenocarcinoma – is frequently associated with other malignancies. Treatment is focused on surgical excision and may require mapping biopsies to plan resection.
• Basal cell carcinoma of the perianal region is treated with wide local excision.
• Gastrointestinal stromal tumors can be managed with wide local excision or radical excision depending on margin status. Preoperative treatment with tyrosine kinase inhibitors may enhance resectability.