Frequently Asked Questions

The anus is the very end of the digestive system, just below the colon and the rectum. Anal cancer is cancer of the skin lining the anus. It is different from colorectal cancer, and sometimes missed during routine colonoscopies (exams to look for colorectal cancer).

About 90% of anal cancers are caused by the Human Papillomavirus or HPV. There are many strains or types of HPV and not all of them cause cancer. Most cancers of the cervix and anus are caused by HPV strains 16 and 18. Other HPV strains cause genital warts. HPV is the most common sexually transmitted disease and most people are exposed to HPV over their lifetime. HPV infection usually goes away on its own. However, when the immune system is damaged by HIV, HPV infection can last longer and cause changes to the skin inside the anus called “dysplasia.” Over time, some of these HPV-damaged cells (which are called “High-Grade Squamous Intraepithelial Lesions” or HSIL) can develop into cancer. HSIL is not the same as cancer, but it is a warning sign that cancer may one day develop in that spot. We don’t know why some HSIL go away on their own while others get worse and develop into cancer.

Anyone can get anal cancer, but it is much more common for people who are HIV-positive than HIV-negative. For perspective, in HIV-negative people the chance of developing anal cancer is 1-2 people per 100,000. In HIV-positive people it is between 30-131 per 100,000. (The rate in HIV positive women is lower than in men.) Even those on successful antiretroviral therapy have a higher risk of anal cancer than HIV-negative people. People who have never had anal sex can still get anal cancer.

People living with HIV (PWHIV) have the highest risk of anal cancer. The lifetime risk of anal cancer can be as high as 10% of people with anal high grade squamous intraepithelial lesions, or HSIL. In the general population, anal cancer occurs most often in women.

Anal pre-cancer is called HSIL. Anal HSIL is an area of abnormal skin growth of the anus. Anal HSIL and anal cancer is caused by the human papillomavirus (HPV). Some types of this virus cause warts and some types cause pre-cancer and cancer. Most of the time, anal HSIL does not progress to anal cancer. However, it can become anal cancer in about 10% of PWHIV with HSIL.

The early stages of anal cancer usually have no symptoms which means most people are unaware when they begin to develop cancer. In later stages the most common symptom reported is pain, which can be felt constantly or felt only when using your anus to go to the bathroom or have sex. A lump or bleeding from the anus can also be symptoms of anal cancer. Anal cancer is often misdiagnosed as a hemorrhoid. If you are having any of these symptoms it’s important to tell your doctor.

Doctors may do an anal pap smear (a swab rubbed against the skin inside the anus) to find abnormal cells. High resolution anoscopy, or HRA, is an anal exam with a special microscope to find pre-cancer and cancer. During HRA, the health care provider takes a biopsy (cuts off a small piece of skin) if any areas look abnormal. Another doctor looks at the tissue under a microscope to decide if the biopsy is HSIL or cancer.

When caught early, anal cancer usually responds well to treatment. Some small cancers can be removed surgically. However, once the cancer spreads treatment may require a combination of drugs (chemotherapy), radiation, and surgery. The earlier anal cancer is found and treated, the fewer side effects from treatment. 

Removing the affected areas can “cure” anal cancer but there are often long term side effects from the surgery, radiation, and chemotherapy. People with a history of anal cancer need to be checked regularly to make sure the cancer doesn’t grow back.

• Infection with certain strains of Human Papillomavirus (HPV)
• Age - risk goes up as you get older
• Having a low CD4 count in the past
• Smoking
• For women: A history of HPV related cervical and vulvar dysplasia and/or cancers
• History of genital warts

• http://analcancerinfo.ucsf.edu a website of the UCSF ANAL Cancer Center for Research and Education.

Follow the links below to hear from men and women who have had anal cancer:

• Thriver Stories. These are the stories of anal cancer thrivers. We prefer to use the word thriver because surviving isn’t enough — we believe that every person with cancer should be empowered with the resources to thrive. We welcome you to read the experiences of others who have had anal cancer and encourage you to send your own stories to info [at] analcancerfoundation.org. Please note that these individuals speak about their treatment plans. Speak to your doctor about what is right for you.
• Anal cancer Survivor - David's Story. David shares his personal experience with anal cancer: his initial reaction to the diagnosis; the battle coming to terms with it; facing the treatment options and finally overcoming the cancer.
• Anal Cancer: Living Life Four Months At A Time. Nearly two years ago, Michele Longabaugh was told she had anal cancer. Yet, she says, she had none of the risk factors. This is part one of a two-part series focusing on anal cancer and how one woman lives life four months at a time and copes with the stigma that comes with it. The four months is the length between her CT scans that will tell her if her cancer has returned. Michele agreed to do the story and has created an incredible and intimate blog that details her struggle with anal cancer. When you access it, go to the archives and start at the beginning. It was and is Michele's way of coping with a disease that no one wants to talk about.
• Living and Thriving After Treatment for Anal Cancer: Addressing Long-Term Treatment Side Effects. At an educational forum for anal cancer survivors, a panel of experts discussed side effects often experienced by individuals treated for anal cancer. Panelists addressed the short and long-term quality of life effects after chemotherapy and radiation and management of these side effects. This event was sponsored by The HPV and Anal Cancer Foundation, the UCSF Helen Diller Family Comprehensive Cancer Center, and the Farrah Fawcett Foundation. Co-sponsors include the UCSF Alliance Health Project, Project Inform, the Shanti Project, and the International Anal Neoplasia Society.

HPV (Human Papillomavirus) is the name of a group of sexually transmitted viruses that includes more than 80 different strains or types. HPV is one of the most common STDs in the world. HPV is the cause of warts which usually appear in the groin area. HPV strains 16 and 18 are more likely to cause cancer in the cervix and anus. Most people who become infected with HPV will not have any symptoms and will clear the infection on their own. HIV positive people may take longer to clear the HPV infection, increasing their risk of developing cancer.

HPV can be passed from person to person, even when there are no signs of infection. Although condoms do reduce the chance of infection, they don't offer complete protection against the virus since HPV can be easily spread by skin-to-skin contact with areas of the body not covered by condoms. Because HPV is spread through skin-to-skin contact, both men and women who are sexually active are at risk for getting HPV .

Yes, men who have sex with men do have higher rates of HPV infection than heterosexual men. At some point in their lives:

• At least 50 percent of all sexually active men get HPV
• More than 65% of HIV negative gay men get HPV
• More than 90% of HIV positive gay men get HPV

Genital warts are the most easily recognizable sign of HPV infection. Genital warts are single or multiple growths that appear around the anus or on the penis, testicles, groin or thighs.Warts may appear within weeks or months after sex with someone who is infected. Sometimes, the virus remains 'silent' in someone's system -- in these cases, the people never develop warts even though they have the type of HPV that causes them. Genital warts can be surgically removed, frozen off or treated with medication. Warts sometimes do return, especially within the first few months of treatment.

Unfortunately, there is no cure for HPV. The good news is that most people who become infected with HPV clear the virus on their own (which means that the virus won't cause them any long term harm). There are several vaccines to prevent HPV infection in boys and girls. These vaccines must be given before a person is exposed to HPV. But once a person is exposed to HPV, there is no cure, just treatment of the warts and lesions caused by HPV.

Most HPV infections do not cause cancers, but some do. The types of HPV that can cause genital warts are not the same as the types that can cause anal cancer. In a small number of people, certain strains of HPV can cause abnormal skin cells to grow in the anal canal. Sometimes, these changes can gradually worsen and develop into pre-cancerous cells. If left unchecked, in a small proportion of people, anal cancer can develop over a period of many years.

Unfortunately, there are no approved tests to detect the early evidence of HPV-related cancers in men. Women, however, do have an approved test -- the PAP smear. Once abnormal growths have formed, which can take 20 - 30 years, they can often be detected during a routine digital rectal exam or anoscopy.