Further tests for cancer of unknown primary (CUP)
Your specialist will usually arrange for you to have some of these tests. In some people, these tests will diagnose the primary cancer.
We can’t list all the possible tests you may have here, but we’ve included those most likely to be used depending on your symptoms. Your hospital will give you information about how to prepare for any tests and what to expect.
These are taken to check your lungs or other parts of the body, such as the bones.
CT (computerised tomography) scanBack to top
A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body. The scan takes 10-30 minutes and is painless. It uses a small amount of radiation, which is very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.
You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It’s important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection.
You’ll probably be able to go home as soon as the scan is over.
Hear from a superintendent radiographer in CT, and Jyoti, a CT scan patient, about what to expect when having a CT scan.
This is a combination of a CT scan and a positron emission tomography (PET) scan.
A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body. PET/CT scans give more detailed information about the part of the body being scanned. You may have to travel to a specialist centre to have one.
You can’t eat for six hours before the scan, although you may be able to drink. A mildly radioactive substance is injected into a vein, usually in your arm. The radiation dose used is very small. The scan is done after at least an hour’s wait. It usually takes 30–90 minutes. You should be able to go home after the scan.
MRI (magnetic resonance imaging) scanBack to top
This test uses magnetism to build up a detailed picture of areas of your body. It’s sometimes used to look for a cancer in the breast if there is cancer in the lymph nodes in the armpit.
The scanner is a powerful magnet so you may be asked to complete and sign a checklist to make sure it’s safe for you. The checklist asks about any metal implants you may have, for example a pacemaker, surgical clips and bone pins. You should also tell your doctor if you’ve ever worked with metal or in the metal industry as very tiny fragments of metal can sometimes lodge in the body. If you do have any metal in your body it’s likely that you won’t be able to have an MRI scan. In this situation another type of scan can be used.
Before the scan, you’ll be asked to remove any metal belongings including jewellery. Some people are given an injection of dye into a vein in the arm, which doesn’t usually cause discomfort. This is called a contrast medium and can help the images from the scan to show up more clearly.
During the test you’ll lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It’s painless but can be slightly uncomfortable, and some people feel a bit claustrophobic. It’s also noisy, but you’ll be given earplugs or headphones. You can hear, and speak to, the person operating the scanner.
Ultrasound scans use sound waves to build up a picture of organs such as the abdomen, liver and pelvis. A gel is spread onto the skin and a small device is passed over the area. This shows a picture of the area on a screen. An ultrasound only takes a few minutes and is also sometimes used to guide a biopsy.
If you have a pelvic ultrasound you’ll be asked to drink plenty of fluids so your bladder is full. This helps to give a clear picture. Some women have a vaginal ultrasound instead of a pelvic one and you don’t need to have a full bladder for this.
An endoscopy is a test to look inside the body. An endoscope is a thin, flexible tube with a camera on the end. It also has a small cutting instrument that allows the doctors to take biopsies of any abnormal areas.
Before the test, you may be given a sedative to help you relax and make you feel sleepy.
Below are the common types of endoscopy.
The endoscope is passed up your nose and into your throat (nasendoscopy) or through the mouth and down your throat (laryngoscopy). This is so the doctor or nurse can look closely at the back of your mouth and larynx (voicebox).
A doctor or nurse uses an endoscope to examine the inside of the lung airways. They use a type of endoscope called a bronchoscope. They may give you a mild sedative to help you relax. The doctor or nurse will spray a local anaesthetic on the back of your throat to numb it. They’ll then gently pass the bronchoscope into your nose or mouth and down into the lung airways. The test may be slightly uncomfortable but it only takes a few minutes.
Upper gastro-intestinal endoscopy
You’ll be asked to lie on your side on a couch. The doctor or nurse will ask you to swallow the first part of the endoscope. They will then gently ease it further down the gullet (oesophagus), into the stomach and the first part of the small bowel (duodenum).
You’ll be asked to lie curled up on your left side while a tube is gently passed into the back passage. The doctor or nurse can then examine the whole length of the large bowel (colon).
If just the lower part of the bowel is examined, the procedure is called a sigmoidoscopy. If just the rectum is examined, it’s called a proctoscopy.
A doctor or nurse uses an endoscope to examine the inside of the bladder.
This procedure allows the doctor to look inside the tummy (abdomen) and pelvis. It’s done under a general anaesthetic and you need a short stay in hospital.
This is like an endoscopy but the tip of the endoscope has an ultrasound probe on it. It uses sound waves to build up a picture of the area.
Video-assisted thoracoscopic surgery (VATS)Back to top
This is a small operation that uses keyhole surgery. A small cut (less than an inch) is made between the ribs so that an endoscope can be put inside. This is to examine the surface of the lungs and take biopsies. A general anaesthetic will be used. VATS may be done when a biopsy can’t be taken through the skin.
A mammogram is a low-dose x-ray of the breast. It may be done if a woman has symptoms that suggest breast cancer, such as cancer in the lymph nodes of the armpit, but no primary cancer in the breast.
The person who takes the x-ray is called a radiographer. They will position you so your breast is against the x-ray machine and gently compressed with a flat, clear, plastic plate. Two mammograms (from different angles) are taken of each breast.
Most women find having a mammogram uncomfortable or a bit painful, but the test doesn’t take long.
Blood, urine and faecal testsBack to top
Your blood, urine and stool (faeces) will also be tested.
These are done to check:
- how organs such as your liver and kidneys are working
- the number of different blood cells you are producing (your blood count).
A low number of red blood cells (anaemia) may mean that there’s some bleeding inside your body. This could possibly be from a cancer in the bowel or stomach. Lots of changes to the blood cells may mean that a cancer is affecting the bone marrow where blood cells are made.
Some cancers produce chemicals that can be measured in the blood. These are called tumour markers. High levels of a marker may suggest a certain type of cancer. The markers can be raised in conditions other than cancer, so they aren’t always reliable.
Your specialist may use different tumour markers to help them make a diagnosis:
- PSA (prostate-specific antigen) to check for prostate cancer.
- Human chorionic gonadotrophin (HCG) to check for germ cell tumours – a rare type of cancer that can start in the testicles or ovaries.
- Alpha-fetoprotein (AFP) to check for some types of germ cell tumour and some types of primary liver cancer.
- CA125 to check for ovarian cancer.
- CA19-9 to check for cancer in the pancreas or bile ducts.
- Carcinoembryonic antigen (CEA) to check for bowel cancer.
- Chromogranin A (CgA) to check for neuroendocrine cancers – rare cancers affecting the neuroendocrine system that produces the body’s hormones.
Urine tests (urine cytology)
Samples of your urine can be tested for abnormal cells and to see how well your kidneys or bladder are working. Rare cancers, such as neuroendocrine cancers, produce extra hormones that can be measured in the urine. You may need to collect your urine for 24 hours for this test.
FOB (faecal occult blood) test
A small sample of your stool (faeces) can be tested for tiny amounts of hidden blood in your bowel motions. Occult blood means blood that is not visible to the eye.