Anal Cancer Risk and Prevention
Many people have no risk factors for anal cancer. However, some things can increase risk, including:
- Having the human papillomavirus (HPV) infection — 95% of people with anal cancer have HPV
- A weakened immune system, caused by taking drugs that suppress one’s immune system
- Having an organ transplant
- A history of cancer, including cervical, vulvar, or vaginal cancer
- Engaging in receptive anal sex
- A history of genital warts
- Smoking
People who think they may be at risk should discuss it with their doctor. While there is no way to completely prevent anal cancer, taking the following precautions may reduce your risk:
- Receive the HPV vaccine. This safe and effective shot is recommended for children starting at age nine and young adults up to age 26. Individuals aged 27-45 may still benefit from the vaccine and are encouraged to speak with their doctor.
- Practice safer sex.
- Get screened regularly if you have HIV or other immune problems.
Anal Cancer Diagnosis and Tests
In addition to considering a patient’s medical history and assessing their risk factors, the following tests and procedures may be used to diagnose anal cancer:
- Physical exam
- Digital rectal exam
- Anoscopy or endoscopy — which are procedures used to view the inside of the intestinal tract
- Imaging tests, including FDG PET-CT, and in some cases, a CT scan or an MRI
- Examination of lymph nodes in the groin to evaluate possible spread, since the groin area is the most common area for anal cancer to spread
- Biopsy
Patients receiving care at another hospital may be interested in a second opinion. Dana-Farber's Second Opinion Program is available for those who are newly diagnosed, whose condition has changed, or whose care team recommends a new treatment plan. Second opinion appointments may be conducted in-person or online.
Anal Cancer Management and Treatment
Anal cancer stages can be described using a scale from stage 0 to stage IV. A higher stage number indicates a more advanced cancer. Three factors are used to help determine the cancer stage: the size of the tumor, whether the cancer has spread to nearby lymph nodes, and whether the cancer has spread to distant lymph nodes or organs. The stage of a cancer helps determine its severity as well as how to treat it.
Stages of Anal Cancer
- Stage 0 (carcinoma in situ) — This is the earliest anal cancer stage; abnormal cells are only found in the mucosa (innermost layer) of the anus.
- Stage I (also called stage 1) — Tumors are 2 centimeters or smaller. Cancer has not spread to nearby lymph nodes.
- Stage II (also called stage 2) — This stage is divided into stages IIA and IIB.
- In stage IIA, the tumor is larger than two centimeters but not larger than five centimeters. Cancer has not spread to nearby lymph nodes.
- In stage IIB, the tumor is larger than five centimeters and cancer has spread to lymph nodes near the rectum, but not to distant parts of the body.
- Stage III (also called stage 3) — This stage is divided into stages IIIA, IIIB, and IIIC.
- In stage IIIA, the tumor is five centimeters or smaller. Cancer may have spread to lymph nodes near the rectum, but not to distant parts of the body.
- In stage IIIB, the tumor is any size and has spread to nearby organs, such as the vagina, urethra, or bladder. Cancer has not spread to nearby lymph nodes.
- In stage IIIC, the tumor is any size and may have spread to nearby organs. Cancer has spread to lymph nodes near the anus or groin.
- Stage IV (also called stage 4) — In stage 4, the cancer can be any size and may or may not have grown into nearby organs. Cancer may or may not have spread to nearby lymph nodes. The cancer has likely spread to distant organs, such as the liver or lungs, and is also known as metastatic.
Our Multidisciplinary Team Approach
Dana-Farber’s Gastrointestinal (GI) Cancer Treatment Center uses a multidisciplinary approach to care for patients diagnosed with anal cancer. Our expert team of medical, radiation, and surgical sub-specialists works together to determine your best course of treatment. Since anal cancer is a rare form of cancer, it is especially important to be seen by experts who have experience treating it and managing the treatment’s potential side effects.
Meet The GI CENTER Team
Treatment Options for Anal Cancer
Common treatment options for anal cancer may include:
- Radiation therapy
- Chemotherapy
The standard care for anal cancer that has not metastasized to another organ is radiation therapy and chemotherapy. Radiation is directed to the tumor itself and the lymph nodes around the groin (if appropriate), five days a week for six weeks. Chemotherapy is given intravenously in the first and fifth weeks of radiation. Some cancer treatment centers use chemotherapy pills rather than intravenous (IV) chemotherapy. Chemotherapy generally consists of two drugs:
- 5-fluorouracil (5-FU): This is the main chemotherapy drug used for anal cancer. In some cases, capecitabine may be used instead.
- Mitomycin C: Determining the proper dosage of mitomycin C requires expert knowledge. Our medical oncologists are highly skilled in medication management. In special situations, cisplatin may be prescribed instead of mitomycin C.
Researchers at Dana-Farber are exploring new approaches to anal cancer treatment, including using immune therapy for early-stage disease and reducing the radiation dose for patients with small anal tumors.
After chemo and radiation are completed, scans and exams will be done to check if the cancer has responded to treatment. Most patients with localized anal cancer — meaning cancer that hasn’t spread to lymph nodes or other organs — can be cured with chemotherapy and radiation.
Advanced Anal Cancer Treatment
Sometimes, anal cancer can reoccur after treatment. For anal cancer that returns to the anus or isn't eliminated by chemotherapy and radiation, surgery may be an option to remove the recurrent disease.
For patients who have metastatic anal cancer, initial treatment usually involves chemotherapy. In some cases, radiation and immunotherapy may be recommended. Patients with metastatic disease may also consider participating in a clinical trial as part of their treatment plan.
Our Center also conducts important research on anal cancer and runs clinical trials to develop promising new treatments. Research involving HPV-positive cancers — which help with the treatment of anal cancer — is a current focus area.
Find clinical trials that are being conducted at Dana-Farber, and learn more about Gastrointestinal Cancer Clinical Trials and Research.
