What is anal cancer?
Anal cancer involves the skin surrounding the anus (where stool exits your colon and rectum) as well as the anal canal (opening) itself. It is rare–much less common than cancer of the colon or rectum. The American Cancer Society estimates for anal cancer in the United States for 2024 are:
Am I at risk for anal cancer?
While everyone has the potential to develop anal cancer, the risk is much higher in several populations, including people with HIV, men who have sex with men (MSM), solid organ transplant recipients, and women with a history of vulvar cancer or precancer. These groups all have at least a ten times increased rate of anal cancer, with some groups being even higher, such as MSM who are HIV+. Other elevated risk groups include people with a history of vaginal or cervical pre-cancer or cancer, people with a history of anal warts, persistent (>1 year) high risk subtype HPV infection and patients with autoimmune conditions or requiring immunosuppressive medications. The number of new anal cancer cases has been rising for many years. Anal cancer is rare in people younger than 35 and is found mainly in older adults, with an average age being in the early 60s. It is also more common in White women and Black men. Prevention and screening of high-risk populations are key parts in decreasing the rates of anal cancer and effectively treating the disease when it occurs. A recent study (ANCHOR) shows that treatment of precancerous lesions in high-risk populations will decrease the risk of
anal cancer in the future.
How can I get checked for anal cancer?
There are several screening methods used, especially in high-risk patient populations (see above). Screening methods will be limited to availability of certain procedures in any given region, but you should ask your provider for a referral to the screening and treatment options that best fit your needs.
Regular examination–Any patient with a history of anal and genital warts should have a regular examination for recurrence. The timing of examination will be based on each individual case, but any warts or dysplasia that recur should be closely watched and treated. An examination should include visual inspection, digital rectal examination (feeling inside the anus with a finger for any abnormality) and anoscopy (looking into the anus with a lighted scope) for patients with a history of anal disease. It is important for patients with genital HPV infection to also have an anal examination since the virus spreads through direct contact and is aided by bodily fluids.
Anal cytology–This is the same testing as a Pap smear in a gynecology exam. A moist swab is inserted into the anus (or is self-inserted in some clinics) and random cells are captured and examined under a microscope. If there are abnormal cells present, more testing may be recommended. The swab can also be tested for the presence of the HPV virus. They are not a perfect test and can have false results but have a role in the screening of high-risk patients.
High resolution anoscopy (HRA)–This is a procedure like colposcopy in a gynecology exam. This examination is usually done in the office and is tolerated well by most patients. The anal canal is stained with swabs using a small plastic anoscope and the anal canal and surrounding skin is examined with a special microscope. Biopsies of abnormal areas can be done to determine if there are precancerous changes. A recent study (ANCHOR) showed that examination with HRA in high-risk patients, and treatment of high-grade dysplasia (HSIL) led to decreased rates of anal cancer.
Is there anything that I can do as a patient, especially if I’m at increased risk?
Although few cancers are totally preventable, avoiding risk factors and getting regular checkups are important. Using condoms may reduce, but not get rid of the risk of HPV infection. HPV vaccines (for those ages 9 to 26) have been shown to not only lower the risk of HPV infection, but also reduce the risk of anal cancer in men and women. People at increased risk should talk to their physicians about getting an anal cancer screening. During this test, your physician swabs the anal lining, looking at the cells under a microscope for anything unusual. Other forms of screening include looking closely at the area during a surgery, or in the office with a special scope to look in the anal canal. Early identification and treatment of precancerous areas may help prevent anal cancer.
Guidelines For Anal Cancer Screening
These guidelines are based on an increased risk by a factor of ten (10 times more likely to develop anal cancer over the general populations at the listed ages)
Treatment of Anal Warts/Anal Dysplasia
It is important to get treated for anal warts or anal dysplasia if found on exam. These lesions have a risk of progressing to anal cancer over time, so it is important to get adequate treatment of these and continue with close monitoring as recommended by your surgeon at Sacramento Colon & Rectal Surgery Medical Group. Please go here (hyperlink to Anal Warts/Anal Dysplasia page), for more details.
How is anal cancer treated? Do I need surgery?
When anal cancer develops, it must be diagnosed with a biopsy (taking a piece of tissue for examination). Once there is a definite diagnosis, then studies are performed to decide the stage and to determine if the cancer has any distant spread to other parts of the body. Common imaging studies include ultrasounds, CT scans, MRIs, and PET scans. Early-stage cancers (without spreading to lymph nodes and distant organs) have a high success rate for treatment. Even tumors with local spread can respond to treatment with a high percentage of long-term survival. Patients with an increased risk of anal cancer or with a known HPV infection history should get regular exams so that any cancer that develops is caught early when treatment is most successful.
Treatment of anal cancer includes:
What Happens After Treatment For Anal Cancer?
Most anal cancers are cured with chemotherapy and radiation. If caught early, many cancers that come back after nonsurgical treatment are treated effectively with surgery. While combination radiation/chemotherapy produces more side effects, this approach also results in the best long-term survival rates. After completing this treatment, as many as 70-90% of patients are still alive and cancer free at 5 years.
Regular follow-up with a careful exam by your colon and rectal surgeon at Sacramento Colon & Rectal Surgery is important. During the appointment, he or she will assess the results of treatment and check to see if there are any new signs of anal cancer. You will also continue close follow up with your medical oncologist (your doctor who guided your chemotherapy treatment) and your radiation oncologist (your doctor who guided your radiation therapy).