Anal cancer

Diagnosis

The following tests are performed to diagnose anal cancer:

• Precancerous lesion:
  • Anal Pap smear combined with anoscopy.
  • Risk subtype test: can be followed up upon the risk of cancer to be prevented.
• Cancerous:
  • Digital rectal examination. To examine the anal canal and rectum, doctor will insert a gloved finger with lubrication inside the rectum to palpate for any abnormalities.
  • Visual exam with anoscopy. An anoscope (a short tube with light) is utilized by the doctor to inspect the anal canal and rectum for any abnormalities.
  • Ultrasound of the anal canal.  A small probe is inserted into the anal canal and rectum which uses sound waves to create images of the tissues or organs to check for abnormalities.
  • Biopsy. A small sample of the tissue from the part with abnormalities is sent to a lab for testing under a microscope to check for cancer cells.

Determining the extent of the cancer

Other tests may be recommended by the doctor once there is a final diagnosis such as to check if the cancer has affected the lymph nodes or has spread to other parts of the body. These tests are as follows:

• Computerized Tomography (CT)
• Magnetic Resonance Imaging (MRI)
• Positron Emission Tomography (PET)

The results will determine the stage of anal cancer which ranges from 0 to IV (Roman numerals). The lowest stage means that the cancer is small and localized in the anus. At stage IV, it means that the cancer has spread to other parts of the body. The doctor uses staging to determine which treatment to apply.

Treatment

The treatment is based on the stage of anal cancer, general health of the patient and the patient’s treatment of choice and location of disease.

Combined chemotherapy and radiation (Predominantly use)

Chemotherapy and radiation therapy are combined to have a higher chance for successful treatment. 

• Chemotherapy. Uses medications which are taken orally or intravenously to kill cancer cells.
• Radiation therapy. High-powered beams by x-rays and protons are utilized to destroy cancer cells in specific areas of the body.

Surgery

• Role of surgery:
  • If the cancer is T1 (<2 cm lesion)
  • Recurrent or persistent of lesion
    Different techniques are utilized by the doctors to remove anal cancer depending on the stage as follows:
• Surgery for early-stage anal cancers. The tumor is removed along with some healthy tissues around it if the size is small. In this case the anal sphincter that controls bowel movement may not be destroyed. Chemotherapy and radiation may also be done after the surgery.
• Abdominoperineal resection for persistent or recurrent lesion (APR).A broader surgery called abdominoperineal resection may be done if the tumor is not responsive to chemotherapy and radiation. This technique removes the anal canal, rectum and a part of the colon. The part of the colon that is left is attached to a stoma (opening of the abdomen) where waste products leave the body and collected into a colostomy bag.

Immunotherapy

Immunotherapy may be applied in advanced cancer stage. This treatment kills cancer cells using your own immune system. Cancer cells release proteins that shield themselves from the body’s disease-fighting immune response. Immunotherapy destroys this process to kill the cancer cells.