A search should be made for the Primary cancer as knowing the Primary site will help decide which drugs to use. So A Pet Scan may guide which part of the body to examine in looking for metastases. The Lung is frequently the Primary site for cancers of unknown origin. Breast, ovary, endometrium, kidney and pancreas must also be help suspect. If no Primary site is found, then the patient is treated as having a cancer of unknown origin.
Chemotherapy is the treatment of choice and control can be achieved for a period of time.
The usually time period is nine to eighteen months. It is helpful to take a piece of the tumor and do a Chemo-Resistant Sensitivity test on it. This test is helpful in ruling out drugs that will not work on that cancer. Surgery and radiation therapy are seldom used. Sometimes after the treatment is started, the Primary cancer will show up and this may help decide which drugs to use.