Anal cancer is a rare type of cancer that affects the very end of the large bowel. Cancer that develops in the cells and tissue of the skin lining on either the inside or outside of the anus is called anal cancer. The anus is an opening to the outside of the body from which stool exits the body. It is below the rectum and is the last part of the gastrointestinal tract.
The symptoms of anal cancer are often similar to more common and less serious conditions affecting the anus, such as piles (haemorrhoids).
The symptoms of anal cancer can include:
- Bleeding from your back passage
- Small lumps around your anus
- Pain or discomfort in the anal area
- An abnormal discharge from your anus
- Anal itching
- Losing control of your bowel movements
Even though these symptoms can be caused by conditions other than cancer, do have them checked by your family doctor.
Anal cancer forms when a genetic mutation turns normal, healthy cells into abnormal cells. Healthy cells grow and multiply at a set rate, eventually dying at a set time. Abnormal cells grow and multiply out of control, and they don't die. The accumulating abnormal cells form a mass (tumor). Cancer cells invade nearby tissues and can separate from an initial tumor to spread elsewhere in the body (metastasize).
Anal cancer is closely related to a sexually transmitted infection called human papillomavirus (HPV). Evidence of HPV is detected in the majority of anal cancers. HPV is thought to be the most common cause of anal cancers.