Anal, perianal cancer

Anal cancer is a rare cancer that develops from the lining of the anal canal.  It presents as a persistent mass (lump) at the edge of the anus that can be quite painful.  It must be kept in mind that most patients with a painful lump at the edge of the anus do not have anal cancer, they have a benign, non-life-threatening condition (such as a fissure, perianal hematoma, thrombosed hemorrhoid, or abscess).  If an anal mass looks at all unusual to the physician, a biopsy (taking a piece of tissue for microscopic analysis) should be performed.  Anal cancer is treated primarily with radiation plus chemotherapy.  Surgery is reserved for those who still have cancerous tissue remaining after this treatment.

Perianal cancer is a cancer that arises in the skin around the anus rather than from within the anal canal.  This is a skin cancer as opposed to a gastrointestinal cancer.  Treatment is either by excision or radiotherapy.  A perianal cancer is more likely going to be suitable for surgical excision than an anal cancer since in a perianal cancer, the anal canal and the sphincter muscles would remain largely intact after excision, whereas to remove an anal canal cancer surgically, one would almost certainly damage these important structures.

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