Carcinoma of unknown primary (CUP) is a term used to describe cancer that has spread to other parts of the body, but the primary site where cancer originated cannot be identified. CUP is a relatively rare diagnosis, and it can be challenging to diagnose and treat because the primary site of the cancer is unknown. The symptoms of CUP vary depending on the organs and tissues where cancer has spread. Diagnosis of CUP may involve a range of tests, including imaging studies, blood tests, and a biopsy of the affected tissue. Treatment for CUP may involve a combination of surgery, chemotherapy, radiation therapy, and targeted therapy, depending on the location and extent of cancer. It is important to work closely with your doctor and healthcare team to develop a personalized treatment plan for CUP, as the best approach will depend on your individual circumstances.

To determine which treatments might be best for you, your doctor will consider where your cancer cells were found, which type of normal cells they most closely resemble and the results of lab tests. The treatment plan is personalized to your particular clinical situation and your personal preferences.

Treatments might include:

• Chemotherapy. Chemotherapy uses drugs to kill cancer cells. One or more chemotherapy drugs may be given through a vein in your arm (intravenously), taken orally, or administered with both methods. Chemotherapy might be recommended if you have cancer cells in more than one area.
• Radiation therapy. Radiation therapy uses high-powered energy beams from sources such as X-rays and protons to kill cancer cells. During radiation therapy, you lie on a table while a machine moves around you, directing radiation to precise points on your body. Radiation therapy might be used for carcinoma of unknown primary that's limited to one area of the body. It can also be used to help control symptoms, such as a growing cancer that's causing pain.
• Surgery. An operation to cut away the cancer might be an option if your carcinoma of unknown primary is limited to one area, such as a lymph node or the liver. Your doctor might recommend radiation after surgery to kill any cancer cells that might remain.
• Supportive (palliative) care. Palliative care is specialized medical care that focuses on providing relief from pain and other symptoms of a serious illness. Palliative care specialists work with you, your family and your other doctors to provide an extra layer of support that complements your ongoing care. Palliative care can be used while undergoing other aggressive treatments, such as surgery, chemotherapy or radiation therapy.