What Is Anal Cancer?
Anal cancer is a rare malignancy that starts in the anus -- the opening at the end of the rectum.
The American Cancer Society estimates that 5,290 new cases of anal cancer will be diagnosed in the U.S in 2009 and that 710 people in the U.S. will die from the disease this year.
For comparison, the American Cancer Society predicts 40,870 new cases of rectal cancer and 106,100 new cases of colon cancer in the U.S. in 2009.
About half of all anal cancers are diagnosed before the malignancy has spread beyond the primary site, while about a third are diagnosed after the cancer has spread to the lymph nodes only and 10% are diagnosed after the cancer has spread to distant organs.
When it is found early, anal cancer is highly treatable.
According to the American Cancer Society, the overall five-year survival rate following diagnosis of anal cancer is 60% for men and 71% for women.
When the cancer is diagnosed in its earliest stage, five-year survival is 82%. If it has spread to surrounding lymph nodes, five-year survival drops to 60%. And when it has spread to distant organs, about 20% of patients live for five years or more.
Who Gets Anal Cancer?
Most anal cancers are diagnosed in people who are between 50 and 80. Before age 50, anal cancer is more common in men, but after age 50 it is slightly more common in women, Saslow says.
Anal infection with human papillomavirus ( HPV) is a major risk factor for the cancer.
According to the American Cancer Society, 85% of anal cancers are associated with persistent infection with the sexually transmitted virus.
Although an HPV vaccine is in use for the prevention of cervical cancer, it is not being given to prevent anal cancer.
"We have some promising data suggesting that the vaccine can prevent anal cancers, but this hasn't been proven," Saslow says.
According to both the American Cancer Society and National Cancer Institute, other risk factors for anal cancer include being over 50 years old, having many sexual partners, having receptive anal intercourse, having a weakened immune system, frequent anal redness and soreness, and being a smoker.
Some tumors that develop in the anus are noncancerous. Others start off as benign but develop into cancer over time.
What Are the Symptoms of Anal Cancer?
In some cases, there are no symptoms associated with anal cancer, but in about half of patients bleeding occurs and is often the first sign of the disease, according to the American Cancer Society.
Because anal itching can also be a symptom of the cancer, many people initially attribute their bleeding and itching to hemorrhoids.
"Any time people have symptoms, they need to get it checked out even if they think they know what it is," Saslow says. "Anal cancer is rare, so it is not on many people's radar screens."
Other signs and symptoms of anal cancer can include:
* Pain or pressure in the anal area
* Unusual discharges from the anus
* Lump near the anus
* Change in bowel habits
How Is Anal Cancer Diagnosed?
Anal cancer can be detected during a routine digital rectal exam or during a minor procedure, such as removal of what is believed to be a hemorrhoid.
The cancer may also be found with more invasive procedures such as an anoscopy, proctoscopy, or endorectal ultrasound.
If cancer is suspected, a biopsy will be done and will be examined by a pathologist.
How Is Anal Cancer Treated?
Standard treatments for anal cancer include surgery, chemotherapy, and radiation.
According to the American Cancer Society, treatment usually involves two or more of these treatment strategies.
Chemotherapy and radiation therapy is currently the most widely used approach to initial treatment.
(Writer Salynn Boyles contributed to this report.)
Common Anporectal Condition
What Is Anal Cancer?