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, 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 450 patients in Ireland per year. (NCRI 2019)