Cancer of unknown primary (CUP) means that cancer spread has been found somewhere in your body (secondary cancer), but your doctors can't find the origin of the primary cancer. CUP is sometimes called unknown primary cancer or unknown primary tumor. It is common in people aged 60 or over, but can affect people younger than this. The primary cancer cannot be found because of the following reasons:
- It may be too small to be picked up on scans or be hidden beside a larger secondary cancer.
- It might have disappeared, even though it has spread to other parts of the body. This can sometimes happen if the body’s immune system has successfully got rid of it.
- It might have been passed out of the body.
Symptoms related to cancer of unknown primary
Signs and symptoms of cancer
of unknown primary (CUP) depend on the location of secondary cancer(s). Symptoms in different areas include:
- Lung secondary cancer: You may experience persistent cough that doesn’t go away, breathlessness or fluid collecting around the lungs.
- Bone secondary cancer: You may have to encounter a dull, persistent pain in the bone that often turns worse in the night. Fracture can also take place is the bone is weakened by cancer.
- Liver secondary cancer: Warning signs include inflammation and pain in the abdomen, feeling sick and loss of appetite, jaundice and fluid collection in the abdomen.
- Lymph nodes secondary cancer: You may experience swollen and hard lymph nodes which can cause discomfort if they’re pressing on tissue or nerves nearby.
You may also have general symptoms including:
Diagnosis of cancer of unknown primary
- Biopsy: It is one of the most important tests which tell the doctor more about the type of cell the cancer developed from. During a biopsy, a small piece of tissue or a sample of cells is removed so that it can be examined under a microscope. But sometimes, it is not possible to perform a biopsy because the cancer is too difficult to reach or a person is too unwell. There are different kinds of biopsy, namely Fine needle aspiration (FNA) biopsy, Core biopsy, Excisional biopsy and Incisional biopsy.
- Removing fluid for testing: Some people have a build-up of fluid next to the lung or they may have a collection of fluid in the tummy. A sample may be taken to examine for cancer cells.
- Bone Marrow Sample: A small sample of bone marrow is taken from the back of the hip bone or occasionally the breast bone so that the doctor can check if the cancer is affecting the bone marrow. However, not everyone will need to have a bone marrow sample taken.
- Examining cells under a microscope: Your doctor will examine the sample to identify the origin and what kind of cell is involved in cancer. If this is not conclusive, more tests can be done on the cells such as Immunohistochemistry tests, Cytogenetic tests and Hormone and protein receptors.
Treatment for cancer of unknown primary
- Chemotherapy: Chemotherapy is the primary treatment for cancer of unknown primary because it treats the whole body. Since the primary cancer cannot be found, it is useful to have a treatment that circulates through the bloodstream. It can then destroy cancer cells irrespective of their location. Hormone therapy is also a treatment for the whole body.
- Surgery: Surgery is not the appropriate treatment for cancer of unknown primary (CUP). But in some cases, for example, if tests on a swollen lymph node show that you have a squamous cell cancer somewhere in your head or neck your doctor may refer to an oncologist.
- Palliative treatment: This type of treatment is often used to treat people with cancer of unknown primary because it slows down the growth of the cancer and relieve symptoms accordingly. The treatment helps patients live longer and comfortably.