Epidemiology

Cancers of the anal region account for <1% of gastrointestinal tumors and <3% of all new cancer diagnoses.[4]

It is estimated that there will be 10,540 new cases of cancers of the anus, anal canal, and anorectum in the US in 2024 and approximately 2190 deaths. Two-thirds of the new cases are expected to occur in women.[5]​​

At least 80% of patients have squamous cell carcinomas.[6][7] Approximately 15% of patients have adenocarcinomas.[6] These have a similar natural history to that of rectal cancer and are treated in a similar way.[8]

For treatment of rectal cancer, see Colorectal cancer.​

The incidence of squamous cell carcinoma of the anus (SCCA) is increasing. One study reported an increase in incidence of SCCA in the US of 2.9% per year between 2000 and 2011.[6] The incidence rate for anal adenocarcinoma remained static during the same period. Another study reported an increase in incidence of SCCA of 2.7% per year between 2001 and 2015, with marked increases in incidence in people aged 50 years and older.[9]

Human papillomavirus (HPV) is detectable in 95% of SCCAs.[10] Immunosuppression likely facilitates persistent anal HPV infection, leading to increased cancer risk. There is a clear association between HIV and anal canal cancer. People living with HIV have a 19-fold increased incidence of anal cancer, compared with people without HIV.[11] Incidence increases with age and is highest in men who have sex with men and people with AIDS.[11][12]

Solid organ transplant recipients have a 6.8-fold increased incidence of anal cancer, compared with the general population.[13] Patients with hematologic malignancies and some autoimmune diseases (Crohn disease, psoriasis, polyarteritis nodosa, and granulomatosis with polyangiitis), also have a higher risk of SCCA compared with the general population.[12][14]

Use of this content is subject to our disclaimer