It is a well known fact that someone with cervical dysplasia resulting from HPV (human papillomavirus) has a high risk of developing anal dysplasia along with anal cancer.
It is unfortunate that the doctors that you would think would be most familiar with performing this type of testing--colorectal surgeons and/or gastroenterologists--more often than not have not heard of it nor do they perform it. I have spoken to dozens of women lamenting their struggles in attempting to find a doctor who would perform an anal Pap.
The purpose of the anal Pap is to determine the presence or absence of the HPV virus in this area. The majority of anal cancers are the result of HPV, and while many know that HPV can result in cervical cancer they are unaware that it can also result in anal cancer.
Before Farrah Fawcett passed away a couple of years ago after a long battle with anal cancer she released a documentary about her experiences with this disease. It was never mentioned that her anal cancer was caused by HPV, though the majority of them are, and many who advocate for those with HPV were outraged that no PSA (Public Service Announcement) was provided at the end to inform people that a vaccine existed to prevent anal cancer caused by certain strains of HPV.
For those who have had an ECC (endocervical curettage) for diagnostic purposes in testing the endocervical canal (the area which connects the vagina to the uterus) the anal Pap is quite similar.
As with an ECC, a small brush-like instrument much like a Q-tip is inserted into the anal canal. The brush is then rotated in a circular motion while it is moved in and out of the anal canal (it sounds a lot worse than it actually is). It is a very quick and relatively painless procedure, but one which can quickly identify whether or not you are harboring the virus within the perianal/anal canal area.
Despite the relative ease of performing such a test, it is very difficult, as mentioned previously, to find someone who will perform it. There are several doctors on either coast of the U.S., Dr. Stephen Goldstone in New York and Dr. Joel Palefsky in Calif., both of whom specialize in HPV related anal cancers.