Cancer of unknown primary (CUP) is when a secondary cancer is diagnosed, but doctors can’t tell where the primary cancer started. The secondary cancer is named according to the primary cancer. For example, a cancer that starts in the lungs and spreads to the liver is still a lung cancer. The secondary cancer in the liver is made up of lung cancer cells and not liver cells.
Secondary cancers are also usually treated according to the primary cancer. Knowing where the cancer started helps the doctors to know what types of treatment to use for the secondary cancer. For example, a lung cancer that has spread to the liver will be treated using lung cancer treatments. It’s treated differently to a cancer that starts in the liver (primary liver cancer).
With CUP, the primary cancer isn’t known. This means that treatment choices are often more difficult to make. (Macmillan.org.uk)
For some patients the origin of the cancer will be found through further tests, however for many patients the primary cancer will never be identified and will remain unknown. A cancer diagnosis in itself is devastating for patients, families and friends, but for the cause of the cancer to be unknown is entirely overwhelming.
Patients diagnosed with CUP need expert coordinated multidisciplinary support, effective communication is vital between teams, patients and their families regarding treatment plans and tests.
Chemotherapy is the main treatment for CUP. Radiotherapy, hormonal therapy and sometimes surgery may also be used.
Cancer of Unknown Primary affects on average 600 patients in Ireland per year with incidence in Sarah’s age group 0-34 in years 1994-2013 of 96 cases, approx 5 per year. (NCRI 2016)
to read more
For information regarding all aspects of CUP please visit www.cupfoundjo.org
Download here a pdf version of ‘Understanding CUP’
For information regarding services in Ireland
Irish Cancer Society – www.cancer.ie
Understanding Cancer of Unknown Primary by the Cancer Council of New South Wales, Australia – https://www.cancercouncil.com.au/65123
Macmillan Cancer Support – http://www.macmillan.org.uk/information-and-support/unknown-primary-cancer
Health Service Executive- www.hse.ie
National Cancer Registry – www.ncri.ie
Cancer Research UK – www.cancerresearchuk.org