WHAT IS ANAL CANCER?
Anal cancer is an abnormal growth in or around the anus. “Squamous Cell Carcinoma” is the most common type of cancer found in this location and has been found to be related to a type of viral infection known as the human papilloma virus (HPV). This virus has been linked to causing other types of cancers including cervical and oropharyngeal cancers. Treatment usually consists of radiation and chemotherapy, and surgery is not always necessary.
HOW COMMON IS ANAL CANCER?
Anal cancer is fairly uncommon and accounts for about 1-2% of all cancers within the gastrointestinal tract. About 1 in 600 men and women will get anal cancer in their lifetime compared to 1 in 20 men and women who will develop colon and rectal cancer in their lifetime. Almost 6,000 new cases of anal cancer are now diagnosed each year in the U.S., and 2/3rds of the cases in women.
WHAT ARE RISK FACTORS FOR ANAL CANCER?
Anal cancer is usually associated with an HPV infection, which is the most common sexually transmitted disease. It is important to note that anal intercourse is not necessary to contracting HPV, and not all anal cancers are associated with HPV infection. Some develop without a clear reason.
Other risk factors include:
- Age – Most cases of anal cancer develop in people over age 55
- Anoreceptive intercourse – Unprotected sex and multiple sexual partners increases this risk
- Smoking – This introduces harmful chemicals which increases the risk of most cancers, including anal cancer.
- Immunosuppression – Certain patients with autoimmune diseases or transplant patients require immunosuppressive medications. Cancer patients may also require drugs that suppress their immune system. HIV patients with low CD4 counts have acquired immunodeficiency putting them at increased risk.
- Chronic local inflammation – Patients with chronic anal wounds are at a slightly higher risk of developing cancer in the area of the inflammation.
- Pelvic radiation – People with previous pelvic radiation for rectal, prostate, bladder or cervical cancer
HOW CAN I PREVENT ANAL CANCER?
The risk of developing anal cancer can be decreased significantly by avoiding the risk factors listed above. Quitting smoking will lower your risk of many types of cancer, including anal cancer. Avoiding HPV and HIV infections with protected intercourse can reduce the risk of developing anal cancer. It is important to note that condoms do not completely prevent transmission of HPV because the virus is spread by skin-to-skin contact and can live in areas not covered by a condom.
HPV vaccination can also decrease the risk of developing anal cancer in men and women. These vaccines are most effective in people who have not previously been sexually active or have not yet been infected with HPV.
Certain patients who exhibit multiple risk factors above may consider screening. This can include anal cytology or “Pap test” and/or high resolution anoscopy (HRA). HRA is a specialized exam that uses high magnification and application of temporary stains to assess for precancerous or cancerous cells in the anus.
Precancerous lesions can be treated with excision, electrocautery ablation, chemotherapy creams (5-fluorouracil or 5-FU), or medications (Imiquimod).
All treatments have potential side effects, and treatment for precancerous lesions differ from those for anal cancer.
WHAT ARE SYMPTOMS OF ANAL CANCER?
About 20% of patients with anal cancers do not have any symptoms especially if the lesion is small and internal. Most patients will experience one or more of the following: anal bleeding, anal pain, discharge, itching, dull/heavy feeling, narrow stools, and swollen lymph nodes.
HOW IS ANAL CANCER DIAGNOSED?
Once there is concern that there may be an abnormal mass in the anus, a biopsy may be performed to identify the pathology. Biopsy of this tissue will be sent to a pathologist who will determine whether this mass is squamous cell carcinoma or something else. If the diagnosis of anal cancer is confirmed, your doctor will likely order additional tests (such as a CT scan) to determine the extent of the cancer. These tests help to stage the cancer in the anus.
WHAT ARE THE STAGES OF ANAL CANCER?
Staging is determined based on the size of the tumor (T stage), lymph node involvement (N stage), and whether the cancer has metastasized to other parts of the body (M stage)
Stage 1 – Smaller than 2cm and no spread outside the anus
Stage 2 – Smaller than 5cm and possible involvement of lymph nodes
Stage 3 – Larger than 5cm or local spread to nearby organs
Stage 4 – Spread to other parts of the body (metastasis)
Patients with stage 1 or early stage 2 disease have about 83% survival after 5 years. Those with late stage 2 or stage 3 cancers have about 67% survival after 5 years. Expected 5 year survival is about 36% for people with stage 4 disease but newer treatments are becoming available all the time which will improve these numbers.
HOW IS ANAL CANCER TREATED?
The following treatment is very effective in curing anal cancer in most cases.
· Radiation Therapy: This is high-dose x-rays used to kill the cancer cells. Anal cancer responds very well radiation therapy especially when chemotherapy is used concurrently. Complications from radiation include skin damage, narrowing of the anal opening, ulcers, diarrhea, fecal urgency, fecal incontinence, bladder inflammation, and small bowel blockages. These complications can occur in both the short- and long-term after undergoing treatments.
· Chemotherapy: These are intravenous medications used to kill cancer cells. Chemotherapy provides an added benefit when used with radiation, and decreases the likelihood of requiring surgical treatment. Medications commonly used for anal cancer include 5-fluorouracil or 5-FU, mitomycin C, and cisplatin. Side effects include nausea, vomiting, diarrhea, hair loss, bone marrow damage, lung inflammation, or nerve changes in the hands and feet.
Most patients are cancer free five years after completing treatments. If the cancer does not go into remission or recurs, surgery may be necessary. The possible surgeries include:
· Local Excision: This is reserved for early stage 1 anal cancers that are external.
· Abdominoperineal Resection (APR): This is for patients whose cancers do not go into remission, recurs after remission, or for symptomatic control. APR surgery involves removal of the anus, rectum, and surrounding muscles followed by creation of a permanent colostomy.
Complications after APR include delayed wound healing, infection, bleeding, and damage to surrounding structures (including ureters, prostate, urethra, and vagina). Many patients with a colostomy live normal lives, maintain an active lifestyle, and can continue to work normally.
Without any treatment for anal cancer, the cancer will continue to grow and ultimately spread. The cancer may cause bowel blockage, abnormal connections (“fistula”) to the vagina or bladder, severe pain as it grows into nerves, bleeding, and fecal incontinence.
AFTER TREATMENT, WHAT IS MY FOLLOW-UP?
Patients in complete remission will get anal examinations periodically every 3-6 months for 5 years. These examinations should be performed by an experienced colorectal surgeon. Patients with stage 2 and 3 anal cancers will get CT scans of the chest, abdomen, and pelvis. This is usually ordered by your oncologist.
CONCLUSION
Anal cancers are rare tumors arising from the anal skin or lining of the anal canal. Early detection and appropriate treatment is associated with a high likelihood of survival. Most tumors are well-treated with a combination of chemotherapy and radiation. In the circumstance where the cancer recurs despite treatment, the cancer may be treated with surgery. It is recommended to follow screening examinations for anal and colorectal cancer. Consult your doctor or colorectal surgeon early when any concerning symptoms occur.
ABOUT COLON AND RECTAL SPECIALISTS
Colon and rectal specialists was founded in 1913. We are a group of dedicated fellowship trained colorectal surgeons. We are experts in the surgical and non-surgical treatment of diseases of the colon, rectum and anus. Our surgeons have all completed advanced surgical training in the treatment of these diseases in addition to full general surgical training. We are well-versed in the treatment of both benign and malignant diseases of the colon, rectum and anus and are able to perform routine screening examinations and surgically treat conditions if indicated to do so.
ABOUT C.A.R.E.S. CENTER
Colon and Rectal Endoscopy and Surgery (CARES) Center is our state-of-the-art Ambulatory Surgery Center. Our center has been accredited by the Accreditation Association for Ambulatory Health Care (AAAHC) and has been given Medicare Deemed Status by CMS. We perform a variety of services including: screening colonoscopies, anal biopsies, high resolution anoscopy (HRA), hemorrhoidectomy, abscess and fistula surgery, fissure surgery, pilonidal surgery, and surgery to treat fecal incontinence. Learn more about us at www.crspecialists.com.
