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Diagnosis Cancer

Anal Cancer

In making a diagnosis of anal cancer, your doctor will first start by recording your medical history. This includes information about your general health, immune status, medications you are taking, and if you are HIV+, your current viral load and CD4+ lymphocyte count.

Your doctor will also ask about any history of anal warts, dysplasia or anal problems. You will also be asked about having a heart valve abnormality that is severe enough to warrant taking antibiotics when you have your teeth cleaned to prevent heart valve infections. If this applies to you, you will be prescribed antibiotics before having any biopsies, which may be part of your cancer diagnosis.

Next, your doctor will ask you to describe any symptoms you are currently experiencing, such as anal itching, discomfort, irritation, pain or difficulty with bowel movements or any problems that occur with anal sex, if applicable.

Your doctor may also recommend the following tests to make a definite diagnosis of anal cancer:

  • Digital Rectal Exam (DRE) A DRE involves the doctor or nurse inserting a gloved, lubricated finger into the rectum to feel for abnormalities. Even in patients without symptoms, something abnormal is usually felt during a DRE. If a mass, a thickening, an area of hardness, a lump, an area of localized tenderness or an ulcer is found, then the patient will be referred to a doctor specializing in anorectal problems who will evaluate and biopsy the suspicious areas.
  • High Resolution Anoscopy (HRA) This test involves looking through a microscope into the anus to look for abnormalities, such as ulcerated areas, thickened areas and lesions containing abnormal vessels. These areas are then assessed and biopsied during an HRA exam.
  • Proctoscopy Also known as a sigmoidoscopy, this is an exam of the rectum using a short, lighted tube called a proctoscope.
  • Endo-anal ultrasound This is a special kind of ultrasound that uses high-energy sound waves to produce pictures of the inside of the body.
  • Rectal Biopsy A rectal biopsy is required to make a definitive diagnosis of invasive anal cancer. Patients with symptoms of anal cancer or those who have any abnormalities felt during a digital rectal exam (DRE) or identified during a high resolution anoscopy (HRA) will have a biopsy. This test involves removing a small amount of tissue from the rectum for examination by a pathologist to make a conclusive diagnosis.


If you are diagnosed with anal cancer, your doctor needs to learn the stage or extent of your disease. Staging is a careful attempt to find out whether the cancer has spread and to what parts of the body. This information also helps your doctor develop the best and most effective treatment plan for your condition. More tests may be performed to help determine the stage.

The various stages of anal cancer include:

  • Stage IS The cancer is in its early stages and is found only in the innermost lining of the anus.
  • Stage I The tumor is two centimeters or smaller in size.
  • Stage II The tumor is larger than two centimeters in size.
  • Stage IIIA A tumor of any size that has spread to nearby organs, such as the vagina, urethra and bladder, or has spread to the lymph nodes by the rectum.
  • Stage IIIB A tumor of any size that has spread to nearby organs such as the vagina, urethra and bladder, and has spread to the lymph nodes by the rectum.
  • A tumor of any size that may have spread to nearby organs, and also has spread to the lymph nodes on one side of the pelvis and/or groin.
  • A tumor of any size that may have spread to nearby organs, and also has spread to the lymph nodes near the rectum and in the groin, and/or to lymph nodes on both sides of the pelvis and/or groin.
  • Stage IV Any cancer that has spread to other distant parts of the body, such as the liver, lungs or brain.
  • Recurrent Recurrent cancer means that the cancer has come back after treatment. The disease may recur in the anus or in another part of the body.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.