All About Anal Cancer: Stages & Treatment Options

Anal cancer is a rare type of cancer that develops in the tissues of the anus and is mostly caused by human papillomavirus (HPV) infections. The American Cancer Society reveals that there will be approximately 9,760 new anal cancer cases in the United States in 2023. 

Once a cancer diagnosis is confirmed, staging becomes a crucial part to determine the most effective course of treatment depending on the spread of the disease. Read on to learn more about the stages of anal cancer and its treatment options. 

How is Anal Cancer Staged? 

Staging for anal cancer involves the TNM system, recommended by the American Joint Committee on Cancer (AJCC). The term TNM is an acronym for Tumor, Node, and Metastases. T determines the tumor size and is measured as T1, T2, T3, or T4. 

• T1- The tumor is 2 centimeters (about 0.79 in) or smaller 
• T2- It is more than 2 centimeters but less than 4 centimeters (about 1.57 in) in size 
• T3- The size of the tumor is between 4 to 6 centimeters (about 2.36 in)  
• T4- It is more than 6 centimeters in size 

N indicates the involvement of lymph nodes in anal cancer. It is measured as N0, N1, N2, or N3.  

• N0- Cancer has not yet spread to the lymph nodes 
• N1- It has spread up to 3 centimeters in the lymph nodes 
• N2- Cancer has spread more than 3 centimeters 
• N3- It has spread further, even to distant lymph nodes 

M indicates metastasized cancer or how farthe disease has spread. It is categorized as M0 or M1. 

• M0- Cancer has not spread to distant organs 
• M1- It has spread to distant organs 

Stages of Anal Cancer  

After assessing the tumor, nodes, and metastases, a healthcare provider determines the stage, ranging from 0 to IV.

1. Stage 0 

It is an early stage of anal cancer, also known as carcinoma in situ (CIS). At this stage, cancerous cells are only found in the top layers of the anal lining and have not spread to other tissues. 

2. Stage I 

However, the disease has not spread to lymph nodes or distant body parts (N0 and M0).

3. Stage II 

Depending on the size of the tumor and the spread of the cancer, stage II is divided into two parts- stage 2A and stage 2B.  

1. Stage 2A means that cancer has spread deeper into the anal wall (T2) and has not yet reached nearby lymph nodes or distant organs (N0, M0).  
2. In stage 2B, the tumor measures no more than 2 inches (T1 or T2) but has already spread to nearby lymph nodes near the rectum (N1). However, cancer does not metastasize to other body parts (M0) in stage 2B. 

4. Stage III 

This stage has 3 subcategories- 3A, 3B, and 3C.  

1. In 3A, the tumor is larger than 5 cm (T3) and it may or may not have spread to nearby lymph nodes (N0 or N1). Stage 3A anal cancer doesn't usually affect distant parts of the body (M0). 
2. Stage 3B means that the tumor has grown larger (T4) and started affecting nearby organs such as the vagina, urethra, prostate gland, or bladder. However, at this stage, cancer does not affect nearby lymph nodes (N0) or distant body parts (M0). 
3. Unlike stage B, stage 3C anal cancer means the disease has already affected the lymph nodes near the rectum (T4, N1, M0).

5. Stage IV 

At this stage, the tumor can be of any size and may or may not have spread to nearby lymph nodes (any T, any N). But the cancer has started spreading to distant organs, such as the liver or the lungs (M1). 

Types of Treatment  

1. Surgery 

It is a common option, particularly for early-stage anal cancer (stages 0 to 2). Depending on the location and size of the tumor and cancerous cells, surgeons may perform a local excision or an abdominoperineal resection. While local excision involves the removal of the tumor and a small amount of surrounding tissue, abdominoperineal resection involves the removal of the anus, rectum, and nearby lymph nodes. 

In some cases, oncologists may recommend surgery in combination with radiation therapy or chemotherapy. 

2. Radiation therapy 

It is another common treatment option for anal cancer, particularly at stages 1 to 3. In the early-stage, doctors recommend radiation as the primary treatment, while in more advanced cases, they often use it in combination with chemotherapy or surgery. Depending on the stage, radiation therapy can be administered externally or internally. 

3. Chemotherapy 

It is more commonly used for advanced cases (stages 2 to 4). Oncologists may administer it with radiation therapy or surgery or use it as the primary treatment for inoperable or metastatic cancer. There are two ways to administer chemotherapy: orally or intravenously (intravenously). 

4. Immunotherapy 

It is a relatively new type of cancer treatment that helps the immune system recognize and attack cancerous cells. Although it is not yet widely used in anal cancer treatment, immunotherapy may be an option in more advanced stages (stage 4), where chemotherapy and radiation therapy are not effective. 

The treatment approach for anal cancer depends on a variety of factors, including the stage and location of the cancer, the patient's overall health, as well as their personal preferences. Individuals should discuss all possible treatment options with their healthcare provider to determine the appropriate course of action for their situation.  

Prognosis  

The survival rate depends on the stage at which cancer is diagnosed. Based on data from the American Cancer Society, the following is the 5-year survival rate for anal cancer. 

• Stage 0 and I: 88%. 
• Stage II: 78-86% 
• Stage III and IV: 48-68%. 

Anal cancer has a high recurrence rate and in 30-50% of cases, it returns. This cancer is usually caused by the human papillomavirus (HPV), and this virus often remains in the body even after initial treatment. Besides, the area is difficult to treat and access, making it difficult to remove cancerous cells or tumors completely. 

Coping and Support  

Being diagnosed with cancer can be overwhelming. However, individuals can regain some sense of control by actively participating in their treatment plan. Stay informed about anal cancer symptoms and keep regular updates on the latest treatment procedures or clinical trials. This will enable individuals to make informed decisions at every step of their treatment. It is crucial to speak to the doctor about all possible treatment options, expected prognosis, and possible side effects of the treatments. Also, stay connected with friends and family to receive emotional support during difficult times. Individuals can also consult a counselor or medical social worker or join a support group.

For any queries or concerns about anal cancer, contact ACTC, one of the best cancer treatment centers in Florida. Contact us at 352-345-4565 or visit our website to schedule an appointment with our board-certified oncologists.