How Does My Doctor Know I Have Anal Cancer?

Pathologist examining tissue under a microscope.

If you’re having symptoms of anal cancer, your doctor will ask you about these things:

  • Your health history

  • Your family’s history of cancer

  • Your other risk factors

Your doctor will also do a careful physical exam, including a digital rectal exam (DRE). During a DRE, the doctor inserts a gloved, lubricated finger into your rectum. The doctor checks for hard or lumpy areas.

If your doctor feels anything unusual or if you have symptoms, he or she may also do certain tests to check if you have anal cancer. You may need more than 1 of these tests:

  • Anoscopy. For this test, your doctor inserts a small lighted tube called an anoscope, which is about 3 to 4 inches long, into the anus to look at the lining. The tube is lubricated before it is inserted.

  • Proctoscopy. For this test, your doctor uses a longer lighted instrument called a proctoscope (which is about 10 inches long) to look at the inside of your anus and rectum. Again, the tube is lubricated before it is inserted.

  • Biopsy. If the doctor sees anything suspicious, he or she may do a biopsy. During a biopsy, the doctor takes a small sample of tissue from your anus. The tissue is sent to a laboratory and looked at under a microscope by a pathologist, a doctor who specializes in diagnosing diseases by examining various body tissues and fluids. A biopsy is the only way to know for sure whether a lesion is malignant (cancerous) or benign (noncancerous).