Diagnosis of Anal Cancer

Executive Summary

Different tests are being conducted for the diagnosis of anal cancer. The diagnosis is entirely dependent upon suspicious cancer type, signs and symptoms, age and general condition of previous medical tests results. The physical examination in anal cancer diagnosis includes rectal examination, anoscopy, biopsy, and other imaging tests includes ultrasound, x-rays, computed tomography (CT) scan, magnetic resonance imaging (MRI), and Positron emission tomography (PET) scan.

Diagnostic approach of Anal Cancer

Doctors use many tests to detect or diagnose anal cancer. They also do tests to see if cancer has spread to other parts of the body from where it started. If this happens, talk about metastasis. The image test shows a picture of the inside of the body. Doctors can also run tests to find out which treatment is most effective. A biopsy is the only surefire method for a doctor to determine if anybody has cancer for most of the cancers. During the biopsy, the doctor takes a tiny sample of the tissue for examination in the laboratory. If a biopsy is not possible, your health practitioner may suggest other tests to help you make a diagnosis of anal cancer. Imaging tests can be used to find out if cancer has spread.

How is Anal Cancer diagnosed?

Many tests can be used for the diagnosis of anal cancer ​1​. Everyone uses not all tests described here. Your doctor may evaluate the following factors when selecting a diagnostic test: 

  • Suspicious Cancer Type
  • Your Signs and Symptoms 
  • Your Age and
  • General Condition Previous Medical Test Results

The physical examination includes the following tests that can be used to diagnose anal cancer-

Rectal Examination (DRE)

The doctor inserts a gloved finger into the anus to look for lumps and other abnormalities during this examination. General cancer guidelines state that men develop DRE after 50 each year, and women undergo regular pelvic tests. If you are at higher risk of acquiring anal cancer, it is recommended that your doctor does DRE more often. 


If the doctor senses a suspicious area during the DRE, this endoscopy can be done to get a closer examination of the anus. Anoscopy allows doctors to see inside the body through a thin, illuminated, flexible tube called an Anoscopy. Similarly, a colonoscopy can observe the rectum in a colonoscopy procedure. A person can be sedated while the probe is inserted into the anus and rectum.


biopsy terminates a small amount of tissue for microscopic examination. Other tests may indicate Anal cancer, but only a biopsy can make a definitive diagnosis. The pathologist then analyzes the sample. A pathologist is a medic who specializes in interpreting laboratory tests and assessing cells, tissues, and organs to diagnose disease. The type of biopsy conducted depends on the location of the tumour. For example, if the lump is small and has not grown into other tissue, an excisional biopsy can remove the entire clot. Lymph nodes can also be removed and examined by biopsy. A biopsy to diagnose anal cancer may be done with local anaesthesia. This can be accomplished in the operating room under general anaesthesia if the area is very uncomfortable. Anaesthesia is a drug that prevents you from feeling pain during a medical procedure.


Ultrasound uses sound waves to create images of internal organs. For anal ultrasound, an ultrasound wand is inserted into the anus to obtain an image. 


X-rays are a method of using a small amount of radiation to create an image of the structure inside the body. 

Computed tomography (CT or CAT) scan

CT scans record images of the body with x-rays from different angles ​2​. The computer then combines these images to create a detailed 3D or 3D image showing the abnormality or anal cancer. You can also use a CT scan to measure the size of the tumor. A special dye called a contrast agent might be given before scanning to provide a more accurate picture of the details of the image. This dye can be injected into the patient’s vein or swallowed as a tablet or liquid.

Magnetic Resonance Imaging (MRI)

MRI scanners use magnetic fields instead of x-rays to generate detailed body images. A special dye called a contrast agent is given before scanning to create a clearer picture.

Positron emission tomography (PET) scan or PETCT scan

PET examinations are usually combined with CT examinations (see above) called PETCT examinations. However, you can hear doctors calling this procedure just a PET scan. PET scans are one way to take pictures of internal organs and tissues. A small amount of radioactive sugar is infused into the patient. This sugar is absorbed by the cells that consume the most energy. Anal Cancer tends to use power aggressively, so it consumes more radioactive material. The scanner then detects this substance and creates an image of the body.

After the diagnostic test is done, your doctor will discuss the results with you. These results will also help doctors explain anal cancer if diagnosed with cancer. This is known as staging.


  1. 1.
    Durot C, Dohan A, Boudiaf M, Servois V, Soyer P, Hoeffel C. Cancer of the Anal Canal: Diagnosis, Staging and Follow-Up with MRI. Korean J Radiol. 2017;18(6):946-956. doi:10.3348/kjr.2017.18.6.946
  2. 2.
    Khatri V, Chopra S. Clinical presentation, imaging, and staging of anal cancer. Surg Oncol Clin N Am. 2004;13(2):295-308. doi:10.1016/j.soc.2004.01.001