Anal Cancer

Q 1. What is anal cancer?

Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus. The anus is the last part of the digestive tract, where bowel movements leave the body.

Q 2 What are the types of anal cancer?

  • Squamous cell carcinoma: It is the most common type of anal cancer.
  • Adenocarcinoma
  • Cloacogenic carcinoma
  • Basal cell carcinoma
  • Melanoma

Q 3 What causes anal cancer?

  • Most important is infection with Human papillomavirus (HPV) virus especially HPV 16,18,31,33 etc. HPV virus is transmitted via the sexual route. Having sex with multiple partners increases the chances of exposure to HPV. 
  • Anal sex
  • Smoking 
  • Older age over 55 
  • Low body immunity from conditions like HIV or from taking medications to suppress the immune system like steroids 

Q 4 What are the symptoms of anal cancer?

  • Pain in or around the anus
  • Bleeding from anus
  • Mass palpable in or around the anus
  • Swelling in the groin area
  • Difficulty in passing motion 

A word of caution

All of these symptoms can also be caused by conditions that are not cancer. Kindly consult your doctor first. 

Q 5 How anal cancer is diagnosed?  

  • The doctor will perform a general physical examination and digital rectal examination (DRE) in which the surgeon will insert a lubricated, gloved finger in anus to feel for signs of disease. 
  • Flexible sigmoidoscopy or colonoscopy to look for synchronous cancer in the lower part of the gastrointestinal tract. 
  • The next biopsy is done from mass to confirm the diagnosis and to know the type of cancer. 
  • Biopsy means removing a small piece of tissue from cancer mass and sent it to a pathologist for examination under a microscope. 

A word of caution

  • There is a common myth that taking biopsy leads to the spread of cancer cells in the body. This is not true. Taking a biopsy does not lead to the spread of cancer cells in the body.
  • Biopsy confirms that it is cancer and not infection and also helps in knowing the type of cancer so that further treatment can be planned accordingly.  

Further testing

Once anal cancer has been diagnosed, further tests are done to look for a local extension of disease and to confirm whether cancer cells have spread to other parts of the body or not. These tests may include:

  • Blood tests – to assess the state of liver, kidneys and bone marrow
  • CT/MRI scan – To find out the local spread of disease 
  • Chest X-ray – to check if cancer has spread to the lungs or not. 
  • PET scan – To know the distant spread of disease 

Q 6 What is anal cancer staging?

Staging is a measurement of how far cancer has spread.

After all the tests have been completed and the results are known, it should be possible to predict what stage the cancer is. The higher the stage, further cancer has spread

Stage I     

Cancer has formed and the tumor is 2 centimeters or smaller.

Stage II

  • In stage IIA, the tumor is larger than 2 centimeters but not larger than 5 centimeters.
  • In stage IIB, the tumor is larger than 5 centimeters.

Stage III

Anal cancer has spread to lymph nodes near the anus or groin, and/or to nearby organs, such as the vaginaurethra, or bladder

Stage IV

Cancer has spread to other parts of the body, such as the liver or lungs.

A word of caution 

The above staging is a simplified version for your basic understanding. The reader is advised to follow the TNM staging system developed by the American Joint Committee on Cancer (AJCC) in which 

  • T stands for the size and location of the primary tumor
  • N stands for nodes. It tells whether cancer has spread to the nearby lymph nodes
  • M stands for metastasis. It tells whether cancer has spread to distant parts of the body

Q 7 How anal cancer is treated? 

Anal cancer is often curable if it’s diagnosed at an early stage. 

When deciding treatment options for a particular patient, the doctor will consider the following factors and will decide the individual treatment plan:

  • The size of the cancer
  • The stage of the cancer
  • The location of the cancer
  • Your overall health and ability to recover from surgery, radiation therapy or chemotherapy
  • How a treatment will affect your bowel movements. 
  • Your personal preferences

Following are the general guidelines but treatment may vary from patient to patient:  

  • Chemotherapy and radiation therapy – Patients with anal cancer, who once were treated surgically, are now treated with chemotherapy and radiation therapy. With this, you may be able to avoid surgery. 
  • Surgery:  Indications for surgery include disease that doesn’t respond to chemoradiation or that recurs

Abdominoperineal resection (APR) is the standard surgery. 

This includes removing the anus, rectum, part of the colon, and lymph nodes. After this surgery, the stool cannot move out of the body along the normal pathway. Instead, the surgeon creates an opening (stoma) in the left lower side of the abdomen and a bag is attached to the stoma to collect waste. Even with a colostomy bag, you can go on with normal activities comfortably.