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Biopsy for cancer of unknown primary (CUP)

A biopsy means taking a sample of tissue so that it can be looked at under a microscope. This is the only way to be certain if an abnormal area is cancer or not.

You might have this test if a scan has shown an abnormal area. Your doctor takes a sample of the abnormal tissue to look at under a microscope. The sample is sent to the lab to be looked at by a specialist doctor called a pathologist.

How you have a biopsy

You might have a biopsy under general anaesthetic, which means you are asleep during the procedure.

Or you might have it under local anaesthetic, which numbs the area before the doctor takes the sample of tissue. Sometimes you may have a drug to make you drowsy (sedation) if you’re having a local anaesthetic.

Doctors use x-rays or scans, such as ultrasound or a CT scan, to help guide many types of biopsy.

Types of biopsy

There are different types of biopsy. The type you have depends on where in the body the abnormal area is.

Your doctor uses a thin needle to go through the skin and into an abnormal area, such as a lump. If the lump is near the surface of your skin, your doctor can just feel where to put the needle in. For lumps deeper in your body they’ll use a scan to help guide the needle.

Your doctor takes out a sample of cells through the needle and into a syringe. They then send the sample to the laboratory.

This is similar to having a fine needle aspiration, but the doctor uses a thicker needle. This means they can remove a larger sample of tissue.

Your doctor may remove the whole abnormal area, if it’s not too large. For example, they may take out a swollen (enlarged) lymph node. Depending on where the abnormal area is, you may have this small operation under local anaesthetic or general anaesthetic.

Your doctor may remove part of an abnormal area if it is large or too complicated to remove.

An endoscopy is a test that looks inside the body, for example in your stomach or bowel. The endoscope is a long flexible tube which has a tiny camera and light on the end of it. Your doctor can see the images on a TV screen.

Diagram of an endoscopy

There are different names for endoscopy depending on which part of the body is being looked at. For example:

  • colonoscopy – to look at the inside of your large bowel (colon)
  • cystoscopy – to look at the inside of your bladder
  • bronchoscopy – to look inside your windpipe (trachea) and lungs
  • ERCP (endoscopic retrograde cholangio pancreatography) – to look at your liver, pancreas and bile ducts

Your doctor might attach an ultrasound probe to the endoscope. This is called an endoscopic ultrasound. Ultrasound uses sound waves to build up a picture of the area. Your doctor might use it to look at the outer layers of the food pipe (oesophagus) or stomach for example, and the area around it. They may be able to see if nearby lymph nodes are swollen (enlarged).

During the test, doctors can put small surgical instruments through the endoscope to take samples of tissue.

In some cases, your doctor may want to take samples of your bone marrow. Bone marrow is the spongy tissue that is inside your bones. It makes your blood cells.

During the test, your doctor uses a needle to remove a sample of liquid bone marrow. They may then use a second needle to take out a piece of more solid bone marrow tissue. This is usually from the back of your hip bone. 

Diagram showing a bone marrow test

After the test

Your doctor sends the biopsy samples to the laboratory, where a specialist doctor (pathologist) looks at the cells under the microscope.

You may go home the same day as your biopsy or the next day. This will depend on the type of biopsy you have and where in the body the biopsy is taken from.

Your doctor or nurse will tell you if you need to follow any instructions when you get home, such as how to care for your wound if you have one. They will also tell you who to contact if you have any problems after your biopsy.

Getting your results

You usually get the results within 2 weeks. The doctor who arranged the biopsy will give them to you.

Waiting for test results can be worrying. It may help to talk to a close friend or relative about how you feel.

For support and information, you can call the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.
Last reviewed: 
22 May 2020
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