Skin Cancer (Non-Melanoma): Diagnosis

Approved by the Cancer.Net Editorial Board, 02/2022

ON THIS PAGE: You will find a description of the common test doctors use to find out whether a suspicious mole, slow-healing sore, or other skin feature is cancerous. Use the menu to see other pages.

More than 75% of non-melanoma skin cancers are first noticed by patients or family members. That is why it is important to bring any suspicious area on your skin to a doctor’s attention. Doctors use many tests to find, or diagnose, cancer. They also do tests to learn if cancer has spread to another part of the body from where it started. If the cancer has spread, it is called metastasis. Doctors may also do tests to learn which treatments could work best.

How skin cancer is diagnosed

For most types of cancer, a biopsy is the only sure way for the doctor to know if an area of the body has cancer. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

Because non-melanoma skin cancer rarely spreads, a biopsy is often the only test needed to diagnose and find out the stage, or extent, of cancer. A biopsy is the removal of a small amount of tissue for examination under a microscope. During this procedure, the suspected skin lesion is removed, usually after a local anesthetic is used to numb the area. The doctor also often removes an area of healthy tissue around the lesion, which is called the margin.

The sample removed during the biopsy is then analyzed by a pathologist who determines if it is a skin cancer. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease.

Your doctor will review the results of the biopsy with you. No further treatment beyond the biopsy may be necessary if the entire cancer was removed. However, if cancer cells were found in the margins of the removed tissue, additional treatment will usually be recommended. See more in the Types of Treatment section of this guide.

Learn more about how a biopsy is used to make a diagnosis.

The next section in this guide is Stages. It explains the system doctors use to describe the extent of the skin cancer. Use the menu to choose a different section to read in this guide.