Anal Cancer Testing, Diagnosis, Stages, and Prognosis

The multidisciplinary teams at Banner MD Anderson Cancer Center bring together expertise from across the medical and cancer treatment spectrum to give you advanced and compassionate care. We are more than experts in oncology, we are here to make sure you understand the treatment process and what to expect, as well as answer any questions you may have.

What Tests Screen for Anal Cancer?

There are different tests available for detecting anal cancer and your doctor will determine which is best based on the symptoms you’re experiencing as well as your risk factors.

Physical Exam

A physical rectal exam allows your doctor to feel for any abnormalities by inserting a gloved, lubricated finger into your anus. Any diagnosis typically begins a physical exam.

Scoping Procedures

  • Anoscopy: a short tube with a camera is inserted into the anal canal, anus and lower rectum, allowing your doctor to examine the anus for any visible abnormalities.
  • Proctoscopy: a hollow tube, called a proctoscope, is inserted into your anal canal to your rectum. Proctoscopes tend to be longer than anoscopes and are equipped with lights and cameras for enhanced visual examination.
  • Colonoscopy: a much longer and more flexible tube, called a colonoscope, is inserted into the rectum and can take pictures throughout your colon and large intestines to look for any signs of cancer in your gastrointestinal tract.

Biopsy

A biopsy is when a sample of tissue is removed and examined under a microscope to see if any cancerous cells are present. If your doctor sees or feels any abnormalities in your anus or rectum from physical examination or any of the scope tests, they may remove a small sample of tissue to study further. During scoping procedures, the scope equipment can extract the biopsy. A biopsy can also reveal precancerous, abnormal cells that require ongoing monitoring.

Imaging Tests

The following imaging tests can be done either to detect if cancer is present, or, if anal cancer has already been verified, to better understand how far it has spread.

  • Ultrasound uses sound waves to make pictures of internal organs or masses. This test can be used to see how deep the cancer has grown into the tissues near the anus. For anal cancer, the wand is put into the rectum, which can be uncomfortable, but isn’t typically painful.
  • Computed Tomography (CT) scans use x-rays to make detailed cross-sectional images of your body. This is a common test for people with anal cancer because it can help identify if the cancer has spread into the lymph nodes, liver, lungs or other organs. A CT scan can also be used to guide a biopsy needle right into an area that could be cancer.
  • Magnetic Resonance Imaging (MRI) scans use radio waves and strong magnets instead of x-rays to create images of your body’s tissues. This test is sometimes used to see if nearby lymph nodes are enlarged, which might be a sign the cancer has spread there.
  • Positron Emission Tomography (PET) scans create images that show how your tissues are working by revealing the metabolic function of the cells within them. The scan uses a radioactive drug called a tracer to show both normal and abnormal metabolic activity. Because the tracer collects mainly in cancer cells, the cancer shows up on the PET scans more prominently.
  • PET/CT scan combines the advantages of both a CT scan and a PET scan. A CT scan can show more details than a PET scan, so a PET scan is often combined with a CT scan using a special machine that can do both at the same time. This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed image of that area on the CT scan.

Many of these diagnostic tests require preparation. For instance, your doctor may ask that you change your diet shortly before the exam, or you may be administered a laxative or enema prior to examination. Your doctor will talk to you about which test is best for you, how you should prepare and what to expect.

What Are the Stages Anal Cancer?

Diagnostic and imaging tests will determine the cancer’s stage. There are five stages of anal cancer. Your cancer stage will be used as a guide to select the best treatment plan.

  • Stage 1: Cancer has formed a tumor 2 centimeters or smaller.
  • Stage 2: Tumor is larger than 2 centimeters but smaller than 5 centimeters.
  • Stage 3A: Tumor is larger than 5 centimeters and has spread to either lymph nodes near the anus or nearby organs, such as the vagina, urethra or bladder.
  • Stage 3B: Tumor is larger than 5 centimeters and has spread to lymph nodes or organs near the anus as well as lymph nodes or organs on one or both sides of the pelvis.
  • Stage 4: Tumor may be any size, may have spread to nearby lymph nodes and organs and has spread to distant parts of the body.

What Is the Prognosis for Anal Cancer?

Most people with anal cancer can and do recover, and the average survival rate for all stages is around 80%. As with all cancer types, early detection greatly increases successful treatment. Your team at Banner MD Anderson is here to provide leading care and help you understand what a diagnosis of anal cancer means for you.