Anal cancer is a disease in which malignant cells form in the tissues of the anus, the end of the large intestine, below the rectum. The number of new cases of anal cancer was 1.9 per 100,000 men and women a year in the United States, an estimated 8,300 people in 2019, according to federal statistics.
The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer. Being infected with the human papillomavirus (HPV) increases the risk of developing anal cancer. Other risk factors include:
- Having many sexual partners.
- Having receptive anal intercourse (anal sex).
- Being older than 50.
- Frequent anal redness, swelling, and soreness.
- Smoking cigarettes.
Source: National Cancer Institute