Tests for skin cancer
The main test to diagnose skin cancer is to take a sample (biopsy) of the area.
You need to go to your GP if you are worried about an abnormal area of skin. Your GP might refer you to a specialist if they think you have skin cancer. Or they might do a biopsy themselves if they have had the specialist training.
Testing for skin cancer
It’s not always possible to tell the difference between skin cancer and non cancerous skin conditions. Your doctor might put some oil on your skin and use a dermatoscope (like a magnifying glass) to examine the area closely.
Below are pictures of dermatoscopes.
Your doctor takes a sample of skin to find out if you have skin cancer. You might have local anaesthetic to numb the area first. This can depend on the size of the abnormal area and where it is. They send the sample to the laboratory to be looked at under a microscope.
Types of biopsies
There are different types of biopsy including:
Incisional biopsy
Your doctor uses a surgical knife to remove a small piece of the abnormal area. They remove the full thickness of the skin.
They then stitch the area closed. The stitches stay in for about a week. You might need to go back to the clinic to have them removed. Or your doctor might use soluble stitches, which dissolve on their own.
Excisional biopsy
Your doctor uses a surgical knife to remove the whole abnormal area. They also remove a border of healthy tissue from around it.
They then stitch the area closed. The stitches stay in for about a week. You might need to go back to the clinic to have them removed. Or your doctor might use soluble stitches, which dissolve on their own.
Punch biopsy
Your doctor uses a special instrument to take a punch biopsy. They remove a small circle of the full thickness of the skin.
You might need stitches to close the area. Or you might not need them if the area is small, as it will heal well on its own. The stitches stay in for about a week if you have them. You need to go back to the clinic to have them removed. Or your doctor might use soluble stitches, which dissolve on their own.
Shave biopsy
You doctor uses an instrument to shave (slice) off the top layer of skin or lesion.
They usually use a device to seal the blood vessels to stop any bleeding (cauterise). The wound forms a scab and heals without the need for stitches.
Understanding the results of your biopsy
It takes about 2 to 3 weeks to get the results of your biopsy. You usually go back to your GP or skin specialist (dermatologist) for these.
You need treatment to the area if the skin sample contains any cancerous cells. For example, surgery to remove the area completely, or other treatments such as chemotherapy creams.
You might not need any further treatment if you had an excisional biopsy. In the laboratory, the specialist doctor (pathologist) carefully checks the sample under the microscope to make sure there is a border of healthy skin tissue all around it. This is called a healthy margin. You will need more surgery if not enough healthy tissue has been removed. This is important because if any cancer cells are left behind, the cancer can continue to grow.
Other tests
It isn't common for a basal or squamous cell cancer to spread beyond the skin. So you might not need any further tests or treatment.
If you are diagnosed with skin cancer and your doctor feels swollen or enlarged 
next to the cancer, then they might do a lymph node biopsy.
Lymph node biopsy
You might have a lymph node biopsy if your doctor thinks there is a risk your cancer has spread from the skin to the lymph nodes.
CT scan
CT (or CAT) scan stands for computed (axial) tomography. It is a test that uses x-rays and a computer to create detailed pictures of the inside of your body.
You might have this test if your doctor thinks your cancer may have spread to the nearby lymph nodes or another part of the body. This hardly ever happens for basal cell cancers. It is also unlikely for squamous cell cancers if they have been diagnosed early on.
This scan can also be particularly useful if non melanoma skin cancer is affecting the bone.
MRI scan
An MRI is a type of scan that creates pictures using magnetism and radio waves. MRI scans produce pictures from angles all around the body and show up soft tissues very clearly.
An MRI scan can also help show up how cancer might be affecting nearby structures such as the nerves. It’s particularly useful for non melanoma skin cancer that has affected places like the eye or salivary glands.
