Four-fifths of all anal cancers arise from the anal canal.
5280 cases in the US in 2011 with approximately 770 deaths (Jemal A et al).
Account for approximately 2% of gastrointestinal cancer in the U.S. and the incidence has double over the past three decades.
Incidence continues to climb.
90% of cases are squamous cell in origin.
Primarily associated with men having sex with men, however 60% of patients are women.
Risk factors, men having sex with men, multiple sexual partners, history of sexually transmitted disease, receptive anal intercourse, previus human papilloma virus infection, chronically immune suppression, organ transplantation, chroninc steroid use, tobacco use and a history of HIV,
Average age of a paitent is 60 years.
Average age of non-HIV positive patient with anal canal cancer is 60 years.
Average age of HIV positive disease patient with anal canal cancer is in the 40s.
Low tendency to disseminate locoregional is of major importance to the outcome of patients.
80% of patients present with locally advanced disease.
Metastatic disease develops in 15-20% of patients.
Squamous cell cancer of the anus is usually preceded by intraepithelial dysplasia or neoplasia that progresses to invasive cancer.
Clinical exam includes digital examination of the rectum, nodal exam, particularly of the inguinal region, proctoscopy for T staging, CT, MRI or PET scan of chest abdomen and pelvis.
Surgery is curative for locally advanced squamous cell carcinoma of the anal canal, but it requires an abdominal perineal resection, therefore chemoradiation is pref2242ed.
Radiation therapy as a single modality is not effective as combining it with chemotherapy.
Radiation as a single modality results in local control in only 68% of all patients with anal canal cancer T1-T2: 78-81%, T3 63%, And T4 33%.
Preoperative chemotherapy and radiation results in high pathological complete remission rates of 80%.
Optimal treatment of regimen of 5 FU, mitomycin and concurrent radiation therapy.
Surgery is now reserved for residual or recurrent disease.
The most proximal portion of the anal canal drains into the lymph nodes of the inferior mesenteric system.
Inguinal metastases in 10-25% of patients.