- Clinical science
Anal cancer is a rare tumor. Risk factors include infection with human papillomavirus (HPV), immunodeficiency, and receptive anal intercourse. The most common clinical features are rectal bleeding (up to 45% of cases), pruritus ani, and tenderness or pain in the anal area. Anal cancer presents mainly as squamous cell carcinoma and in rare cases as adenocarcinoma or other non-epidermoid cancers. Depending on the exact localization and stage, it requires excision and/or radiochemotherapy. If the condition is treated in its early stages, the prognosis is favorable.
- Incidence: ∼ 8000 cases diagnosed per year in the U.S.
- More common in HIV-positive individuals and men who have sex with men
Epidemiological data refers to the US, unless otherwise specified.
TNM Classification for Anal Cancer
UICC (Union for International Cancer Control) staging of anal carcinoma
|UICC stages|| |
|Stage I||T1, N0|
|Stage II||T2 or T3, N0|
|Stage IIIA||T3, N1 or T4, N0|
|Stage IIIB||any T, N2 or N3 or T4, N1|
- Digital rectal exam
- Biopsy for histology (small tumors are fully excised)
- Staging: endosonography, abdominal ultrasound, abdominal CT, pelvic MRI, chest x-ray/CT
- Histology: primarily squamous cell carcinoma; rarely adenocarcinoma or other non-epidermoid cancers
- Above the anal verge → Anal canal tumors
- Below the anal verge → Anal margin tumors
Anal canal cancer
- Treatment of choice: radiochemotherapy
- Recurrent cancers are treated surgically.
- Anal margin cancer
- Anal cancer of the dentate line: The 5-year survival rate after radiochemotherapy is approx. 80%.
- Anal cancer of the anal verge: The prognosis is favorable if complete local excision is possible. The 5-year survival rate after rectal amputation is approx. 50%.