Anal Cancer Stage III
Stage 3 anal cancer means the cancer has not spread to distant parts of the body, but it may have grown into nearby organs or spread to nearby lymph nodes. Understanding your diagnosis and treatment options can help you make informed decisions about your care.
Table of contents
- What is Stage 3 Anal Cancer?
- Stage 3 Subcategories
- TNM Staging System
- Treatment Options
- Outlook and Curability
What is Stage 3 Anal Cancer?
Stage 3 anal cancer means the cancer has not spread to distant parts of the body, but the cancer can be any size and meets one of the following conditions: it is growing into nearby organs such as the vagina (the birth canal in women), urethra (the tube that carries urine out of the body), or bladder (the organ that stores urine); it has spread to nearby lymph nodes (small bean-shaped organs that are part of the body’s defense system); or it has both grown into nearby organs and spread to nearby lymph nodes.[1]
Doctors stage anal cancer to help guide treatment decisions and predict chances of survival. The most common staging system is the American Joint Committee on Cancer’s TNM system, which divides anal cancer from stage 0 to stage 4.[2]
This information applies specifically to squamous cell cancer, which is the most common type of anal cancer.[1]
Stage 3 Subcategories
Stage 3 is divided into 3 groups: stage 3A, stage 3B, and stage 3C. Each group describes different patterns of cancer spread.[1]
Stage 3A
Stage 3A means the cancer is no bigger than 5 centimeters (about 2 inches). The cancer has spread to nearby lymph nodes in the rectum, pelvis, or the groin. However, it has not spread to other parts of the body.[1]
Stage 3B
Stage 3B means the cancer is any size and is growing into the surrounding organs, such as the bladder, urethra, or vagina. The cancer has not spread to nearby lymph nodes or any other parts of the body.[1]
Stage 3C
Stage 3C means the cancer has spread to nearby lymph nodes but not to other parts of the body. The cancer can be larger than 5 centimeters but has not grown into the surrounding organs such as the urethra, vagina, or bladder.[1]
Stage 3C can also mean a cancer of any size that has grown into organs such as the urethra, vagina, or bladder, as well as the nearby lymph nodes.[1]
TNM Staging System
Doctors use the TNM staging system to describe anal cancer in detail. TNM stands for tumor, node, and metastasis. The letter T describes the size of the tumor, the letter N describes whether there are any cancer cells in the nearby lymph nodes, and the letter M describes whether the cancer has spread elsewhere in the body.[1]
The TNM system describes the cancer in detail, and the number staging system puts these details together to give an overall stage.[1]
In the TNM system, stage 3A is the same as T1, N1, M0 or T2, N1, M0. Stage 3B is the same as T4, N0, M0. Stage 3C is the same as T3, N1, M0 or T4, N1, M0.[1]
Treatment Options
Knowing the stage of the cancer helps your doctor decide which treatment is best for you. Treatment can also depend on where the cancer is in your anus and your general health.[1]
Chemoradiotherapy
The main treatment for stage 3 anal cancer is chemoradiotherapy, which means you have both chemotherapy and radiation therapy at the same time.[1][4]
Chemotherapy uses anti-cancer drugs to destroy cancer cells. These drugs are also called cytotoxic drugs. They circulate throughout the body in the bloodstream. Radiotherapy (also called radiation therapy) uses high energy waves similar to x-rays to kill cancer cells.[1]
Chemoradiotherapy leaves the muscles of the anal sphincter (the muscles that control bowel movements) in place. If it is possible to avoid harming or removing these muscles, your overall quality of life after treatment will be better because you will be able to have bowel movements normally.[4]
During chemoradiotherapy, external radiation therapy is usually given once a day, 5 days a week, for 5 to 6 weeks. Chemotherapy is given every 3 weeks. The chemotherapy drug combination used for stage 3 anal cancer is fluorouracil (also called 5-fluorouracil or 5-FU) and mitomycin. Sometimes capecitabine is used instead of fluorouracil. Extra radiation doses, called a radiation boost, may also be given.[4]
When you have finished your treatment, your doctor will check that the cancer has completely gone. Unfortunately, chemoradiotherapy is not suitable for everyone. Your doctor will talk to you about other options if they feel it is not the best treatment for you.[1]
Surgery
Some people diagnosed with anal cancer may have an abnormal opening or passage between the anus and the surrounding skin. This is called an anal fistula or a perianal fistula. If you have an anal fistula, you will need surgery to repair it before you start chemoradiotherapy for stage 3 anal cancer.[4]
If treatment with chemoradiotherapy does not destroy all the cancer cells, your healthcare team may offer you surgery to remove the rest of the cancer. This is called salvage surgery.[4]
If your doctor thinks there is any cancer left after chemoradiotherapy, they take a sample of tissue (called a biopsy) from the area. If this contains cancer cells, they will talk to you about further treatment. This may include a large operation called an abdominoperineal resection (APR). This surgery removes the rectum, anal sphincter, anus, and muscles around the anus. Your surgeon and anesthetist will make sure you are well enough to have this surgery.[1][4]
An inguinal lymph node dissection may be used to treat stage 3B anal cancer when it has spread to lymph nodes in the groin.[4]
Clinical Trials
You can talk to your doctor about clinical trials that are open to people with anal cancer. Clinical trials look at new ways to prevent, find, and treat cancer.[4]
Outlook and Curability
Stage 3 anal cancer is often curable. Doctors often consider your cancer cured if there are no signs of cancer for at least 5 years. The chances of curing anal cancer are generally best in people who are younger or are in better overall health.[2]
Most people with stage 3 cancer live at least 5 years.[2]
