You usually start by seeing your GP if you have symptoms. They examine you and might refer you for tests or to a specialist. Some people may be diagnosed with cancer of unknown primary during tests for another condition.
If your tests show that you have a secondary cancer, you have further tests to look for the primary tumour (where the cancer first started) and see if it has spread anywhere else in the body. If the primary cancer can't be found, a diagnosis of cancer of unknown primary (CUP) is made.
What happens when you see your GP and how to get the most out of your appointment.
Find out when GPs refer people to a specialist.
Find out about the tests you have to diagnose cancer, and what further tests you might need to help doctors find the primary tumour.