What is anal cancer?
Anal cancer is a squamous cancer, or a cancer of the skin-like cells of the anal canal or perianal skin. It occurs in the anus, the area at the end of the digestive tract below the rectum. The rectum is where the stool (feces) is stored, while the anus is the opening through which the stool leaves the body. Anal cancer happens when cells start to grow abnormally in the anus.
Anal cancer is rare, accounting for just one to two percent of gastrointestinal (GI) cancers. Many cases of anal cancer can be found early because the cancer forms in an area that physicians can see and reach easily.
Most cases of this cancer result from human papillomavirus (HPV), a common infection that spreads through sexual contact. Getting an HPV vaccine can lower your risk of developing anal cancer. It’s best to get the vaccine before you become sexually active, though you can get the vaccine later. Talk to your doctor about whether the vaccine makes sense for you.
Anal cancer is treated by gastroenterologists, medical oncologists, colorectal surgeons, and radiation oncologists. The GI cancer experts at Penn Medicine lead the nation in anal cancer treatment. Our team approach translates to exceptional care and dedication to finding the right treatments for you.
Symptoms of anal cancer
Anal cancer can be mistaken for hemorrhoids because some symptoms, like bleeding, are similar. Sometimes there are no symptoms at all.
Symptoms of anal cancer can include:
- A lump or mass at the anal opening
- Bleeding from the rectum or anus
- Change in bowel movements
- Straining during a bowel movement
- Itching in the anus or discharge
- Mucous or pus discharge from the anus
- Narrowing of the stools
- Pain or pressure around the anus
- Swollen lymph nodes in the groin or anus
Types of anal cancer
The types of anal cancer are based on where the cancerous cells are located—this can be either in the anal canal above the anal verge, or in the perianal skin below the anal verge. The anal verge is the external boundary where the anal canal and perianal skin meet.
Another factor that determines the type of anal cancer is the kind of cell where the cancer started. Most anal cancers start in squamous cells. This is called squamous cell carcinoma. Rarer types of anal cancer are adenocarcinoma and basal cell carcinoma.
Anal canal cancer begins in the anal canal, a one-and-a-half-inch-long tube. It is between the anal sphincter, a muscle that keeps the anus closed and prevents stool from leaking out, and the anal verge, the circle of skin tissue just outside of the digestive tract.
There are several types of cancers that start in the cells lining the anal canal, including adenocarcinoma, melanoma, and carcinoid, but squamous cell carcinoma is the most common type and accounts for about 85 to 90 percent of all anal cancer cases.
Perianal skin cancer, previously called cancer of the anal margin, is a rare type of cancer that begins in the skin outside of the anal opening (perianal). Squamous cell, adenocarcinoma, and basal cell cancers can develop in the perianal skin.
Anal dysplasia is a precancerous condition that occurs when the cells lining the anal canal change abnormally. The most common cause of anal dysplasia is infection with the human papillomavirus (HPV). If left untreated, anal dysplasia can lead to anal cancer. Screening for anal dysplasia is done through an anal Pap test, a procedure in which a colorectal surgeon scrapes cells from the lining of the anus and examines them under a microscope.
Diagnosing anal cancer
Navigating a cancer diagnosis can be difficult. Cancer specialists at Penn Medicine are highly experienced in using the most advanced techniques for diagnosing anal cancer. Once you receive a precise diagnosis, your care team can create the best treatment plan for you.
Treating anal cancer
The main treatment for anal cancer is a combination of chemotherapy and radiation, but the treatment depends on the tumor’s location, type of tumor, and extent of spread (stage). Cancer that begins in the anal canal may require different treatments than cancer that begins in the perianal skin.
Reducing your risk for anal cancer
While cancer cannot be totally prevented, you can significantly reduce your risk for anal cancer with preventative measures like quitting smoking, avoiding unprotected anal intercourse, and using condoms to prevent HIV or HPV infection. If you feel you are at risk, you may benefit from consulting with a risk assessment specialist within Penn Medicine’s Gastrointestinal Cancer Risk Evaluation Program.
Why choose Penn Medicine?
Anal cancer is a rare disease that requires specialized expertise. When you choose Penn Medicine for anal cancer care, you can expect:
- Highly skilled experts: Our board-certified doctors and surgeons have subspecialty fellowship training in treating anal and similar cancers of the digestive tract. Our experts follow evolving cancer research and participate in a wide range of clinical trials, offering options for advanced disease.
- Precise diagnosis: Our doctors treat more anal cancer patients than many other centers, so we have a high level of expertise in diagnosing this rare disease. Our pathologists specialize in GI cancer, ensuring an accurate diagnosis that helps guide our team to the right treatments for you.
- Leading treatment options: We offer the latest anal cancer therapies, including cancer drug innovations such as targeted therapy, immunotherapy, and the latest radiation treatments.
- Team approach: Cancer affects everyone differently. At Penn Medicine, your treatment is coordinated by medical oncologists, colorectal surgeons, and radiation oncologists who collaborate on your treatment plan. A wealth of expertise goes into every recommendation we make.
- One-on-one support: Our GI oncology nurse navigators help you get seen by the appropriate specialists quickly, coordinate appointments, and guide you through the treatment process.
- Trusted care, close to home: You’ll receive expert anal cancer care at convenient locations in the southeastern Pennsylvania and New Jersey area.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.
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