hi there
i found this information on the cancerbackup web site
hope it helps.Unknown pimary is called an occult primary tumour so you might find more if you search using that.
Unknown primary tumour
This information is about unknown primary tumours (UPTs), which are also sometimes called an occult primary malignancy (OPM). It is only natural to be in a state of shock when you have been diagnosed with cancer. It is all the harder to accept when doctors do not seem to be able to identify where the cancer is. This is a fairly rare situation, but one which can cause a lot of distress
A malignant tumour (cancer) is made up of millions of cancer cells. Some of these cells may break away from the original (primary) tumour, and spread to other parts of the body where they may form new tumours. These new tumours are referred to as metastases, or secondary tumours.
The secondary cancer is usually made up of exactly the same type of cancer cells as the primary cancer. This means, for example, that if someone has primary lung cancer that has spread to form secondary tumours in the bones, these bone secondaries will be made up of lung cancer cells. These are quite different from the abnormal bone cells that would form a primary bone cancer. The treatment used for these secondary bone cancers would be designed to treat lung cancer cells, not bone cancer cells.
Some secondary tumours, however, are made up of cells which cannot be identified under the microscope because they look too abnormal, and so it is not possible to tell what kind of a primary cancer they have come from.
Unknown primary tumours
For most people who have cancer, the primary cancer is easy to identify, as their symptoms will have alerted their doctor to the likely cause, and this will have been confirmed by the tests done at the hospital.
In people with an unknown primary tumour, the tests will have found evidence of a secondary cancer but will not have been able to identify the site of the primary cancer.
Why the doctors may not find the primary tumour
There are a number of possible reasons for why the primary might not have been found:
theprimary tumour may have disappeared spontaneously because your immune system may have destroyed the primary tumour, but not the secondaries.The secondaries may have grown and spread very quickly, while the primary is still too small to be seen on x-rays or scans.The primary tumour may be impossible to see on x-rays or scans because it is hidden by several larger secondaries that have grown close to it.It is thought that sometimes tumours of the lining of the digestive system may have been passed out of the body through the bowel.
Tests and investigations
Your doctor may want to do a number of tests in order to try to identify the primary cancer. Exactly which tests you will be asked to have will depend on the clues the doctor has already picked up � for example, the symptoms you have had, your medical history, and where your secondary cancer is.
Unfortunately, it is not possible to describe here all the possible tests that you may be asked to consider. Your doctor, however, should describe to you the purpose of each test.
Tests will probably include an x-ray and a CT scan, blood tests, urine tests and a biopsy (the removal of a small sample of the secondary tumour for examination in the laboratory).
Although it can sometimes be helpful, there is often no real benefit in finding out where the primary cancer started. Your doctors will carefully choose only those tests they feel are absolutely necessary, rather than put you through lots of investigations and tests that may take time and be very tiring, but not make a difference to your overall care.
Information can help to reduce your frustration. Ask your doctor or the other staff looking after you to explain what the tests you are having involve, why they are being done, and what the results mean. If you don't understand their explanation at first, ask again. You may find it helpful to write down the questions you want to ask
good luck
liz
Last edited by Cookey; 07-09-2008 12:37 PM.
