The anus is located at the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. A disease in which malignant (cancer) cells form in the tissues of the anus is known as anal cancer. The peri-anal area is the skin around the outside of the anus. So, the tumors in this area are called skin tumors not the anal cancer. The part of the anus between the rectum and the anal opening is called anal canal which is about 1½ inches long.

The treatment of anal cancer is done in following ways:

Radiation therapy

In radiation therapy, x-rays or other types of radiation are used to kill cancer cells. Two types of radiation therapy are there:

External radiation- It uses a machine outside the body to send radiation toward the cancer.

Internal radiation- This therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters which are placed directly into or near the cancer.

The type and stage of the cancer being treated is the most important criteria for giving radiation therapy to patients.

Chemotherapy

Chemotherapy is a treatment of anal cancer in which drugs are used. It helps to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing.  There are two ways of doing chemotherapy-

Systemic Chemotherapy- In systemic chemotherapy, drugs are taken by mouth or injected into a vein or muscle. The drugs enter the bloodstream and thus reach cancer cells throughout the body.

Regional Chemotherapy- It is a type of chemotherapy which is placed directly into the spinal column, an organ, or a body cavity such as the abdomen; the drugs mainly affect cancer cells in those areas

Again the way the chemotherapy is given depends on the type and stage of the cancer being treated.

Surgery

There are two types of surgeries:

Local resection- The tumors that develop in the lower part of the anus are usually removed with local resection. It can be used if the cancer is small and has not spread. Local resection is basically a surgical procedure in which the tumor is cut from the anus along with some of the healthy tissue around it. This type of procedure save the sphincter muscles so the patient can still control bowel movements.

Abdomino-perineal resection- It is a type of procedure in which the anus, the rectum, and part of the sigmoid colon are removed through an incision made in the abdomen. The doctor or the specialist sews the end of the intestine to an opening, called a stoma that is made in the surface of the abdomen so body waste can be collected in a disposable bag outside of the body. During this operation, lymph nodes are removed that contain cancer.