Unknown Primary: Statistics

Approved by the Cancer.Net Editorial Board, 08/2016

ON THIS PAGE: You will find information about how many people are diagnosed with this type of cancer each year. You will also learn some general information on surviving the disease. Remember, survival rates depend on several factors. To see other pages, use the menu.

CUP is estimated to account for around 2% of all cancer diagnoses in the United States. This is about 34,000 patients will be diagnosed in 2016. The exact number of people diagnosed with CUP each year is not known because some cancers start out being classified as unknown primary, only to have the primary cancer found later. In other cases, the treating physician makes an educated guess as to the site of origin, based on clinical features and x-ray results, and treats the patient for the presumed diagnosis. As new tests that can more accurately determine where a cancer started become available, the number of people diagnosed with CUP will continue to decrease.

People diagnosed with CUP are a diverse group, and prognosis, which is the chance of recovery, varies widely. When all CUP types are looked at together, average survival time is about 9 to 12 months after diagnosis. However, survival rates vary greatly depending on the where the cancer is located, how much it has spread, cancer cell type, treatments, and more.

Often, treatment options are limited for people with CUP, since the cancer has often spread to several parts of the body before it is diagnosed.  However, some patients with CUP have a cancer that can be successfully treated. These differences and survival rates are discussed in the Treatment Options section.

It is important to remember that statistics on how many people survive this type of cancer are an estimate. The estimate comes from data based on thousands of people with CUP in the United States each year. So, your own risk may be different. Doctors cannot say for sure how long anyone will live with CUP. Learn more about understanding statistics.

Statistics adapted from the American Cancer Society.

The next section in this guide is Risk Factors. It explains what factors may increase the chance of developing this disease. Or, use the menu to choose another section to continue reading this guide.