I was unsure if you were asking for yourself or someone else, and whether a secondary cancer has been found. You may find it helpful to read our information about cancer ofunknown primary on our website.
Only the hospital specialist can say what happens next as they know the situation.
It can happen that despite several tests, the primary cancer (the original site where the cancer started) cannot be found. The reason for this is not known, sometimes it might be that the secondary cancer has grown very quickly while the primary cancer is still very small, or another thought is the immune system has successfully attacked the original primary cancer and it has disappeared, while the secondary cancer is still growing (this is not common, but it can happen).
A biopsy will tell the doctors how abnormal the cells are from normal cells, and from the pattern of the cells they may be able to say what cancer it is. For example, if the cancer is found in the lung but the cancer cells look like breast cancer cells then doctors may know it is breast cancer that spread to the lungs.
But it can be that the cancer cells don’t look like any particular type of normal cell. The cells are very abnormal and have not become specialised enough to look like breast cells or lung cells, for example. Cells like this are known as poorly differentiated or undifferentiated.
The pathologist (who studies the biopsies) may get a second opinion from another pathologist. Other tests alongside the biopsy such as scans may be done as well all of which will give the doctors some information.
There can come a point where the doctors will stop looking for the primary cancer if they feel they cannot delay treatment further. The primary cancer may also be found at a later date and a diagnosis can be given.
I hope this is helpful and the link above is useful. Please feel free to get back to us if you need any more information or support. You may find it helpful to talk things through with one of the nurses on our helpline. The number to call is Freephone 0808 800 4040 and the lines are open from 9am till 5pm Monday to Friday.
