Diagnosing cancer of unknown primary (CUP) starts with a full patient history, physical examination and blood tests, as well as X-ray, CT scan and other radiologic studies as needed. Usually a biopsy is done early and reviewed thoroughly under a microscope and a pathology report is created.
A patient’s personal history (e.g., heavy smoking), family history of cancer, pattern of presentation (whether the cancer was seen in the lungs or bones or liver) and pathology can help a doctor narrow down the possible primary sites. Some specialists are even using state-of-the-art genetic and proteomic testing to derive a “signature” from cancer cells that can identify their origins.