Cancer - Unknown Primary

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Early Detection, Diagnosis, and Staging TOPICS

Survival statistics for cancer of unknown primary

Survival rates are often used by doctors as a standard way of discussing a person’s prognosis (outlook). Some patients with cancer may want to know the survival statistics for people in similar situations, while others may not find the numbers helpful, or may even not want to know them. If you decide that you don’t want to know them, stop reading here and skip to the next section.

CUP includes many different cancer types, so it’s hard to provide meaningful survival statistics for these cancers as a group. In general, these are dangerous cancers for several reasons:

  • When they are first diagnosed, these cancers have already spread beyond the site where they started. This means that the types of treatments that are most likely to be curative, such as surgery or radiation therapy, are not likely to result in a cure in most cases.
  • Because the exact type of cancer is not known, it’s harder for doctors to know what treatment is most likely to help the patient.
  • Many cancers of unknown primary are fast-growing and/or fast-spreading cancers.

When all types of CUP are included, the average survival time is about 9 to 12 months after diagnosis. But this can vary widely depending on many factors, including the cancer cell type, where the cancer is found, how far the cancer has spread, a person’s general health, the treatments received, and how well the cancer responds to treatment.

Certain CUPs may have better predicted survival. For example, women who have cancer spread throughout the pelvic cavity may have a stage III or IV ovarian, fallopian tube, or primary peritoneal cancer. If treated like advanced ovarian cancer, these women can be expected to have the same survival. The relative 5-year survival for stage III ovarian cancer is 34% (for more information, see “Survival by ovarian cancer stage” in our document Ovarian Cancer).

Survival statistics can sometimes be useful as a general guide, but they may not accurately represent any one person’s prognosis (outlook). Your doctor is likely to be a good source as to whether these numbers may apply to you, as he or she is familiar with the aspects of your situation.


Last Medical Review: 03/12/2013
Last Revised: 01/31/2014