Although rare, anal cancer is becoming more prevalent in the United States and many other developing countries. The condition develops in the tissues of the anus, which is a short tube that connects the lower part of the large intestine, known as the rectum, to the outside of the body. The anus allows the controlled disposal of body waste during bowel movements. Like cervical cancer , the principal cause of anal cancer is human papillomavirus HPV , a common virus that causes changes in the skin. Anal HPV infection is most commonly acquired through anal intercourse, but it can also be acquired from other genital areas that are infected, particularly from the vulva in women, or from the penis in men. Fingers and toys can probably lead to anal HPV infection as well.
Human Papillomavirus (HPV)
HPV infection - Symptoms and causes - Mayo Clinic
It is a family of over types of viruses that can infect the penis, vulva area outside of the vagina , or anus, and the linings of the vagina, cervix or rectum. Most of the time HPV infection is not serious, does not have any symptoms, and will go away on its own without treatment. The virus is most commonly found on the genitals and anus. It is found less often on the mouth or in the throat. Of the more than types of HPV, about 40 of these affect the genitals. Two types cause 70 per cent of cancers of the cervix, plus a number of less common cancers of the throat, anus, penis, vagina and vulva.
Community pharmacists: Underutilized resources in the HIV care team. Anal cancer typically develops over a period of years, beginning with a precancerous condition called anal dysplasia. Anal dysplasia occurs when clusters of abnormal cells form lesions in the mucosa lining of the anal canal between the anus and the rectum.