Unknown Primary: Statistics

Approved by the Cancer.Net Editorial Board, 03/2022

ON THIS PAGE: You will find information about the number of people who are diagnosed with cancer of unknown primary (CUP) each year. You will also read general information on surviving the disease. Remember, survival rates depend on several factors. Use the menu to see other pages.

CUP is estimated to account for around 2% of all cancer diagnoses in the United States. This means about 30,620 people (16,240 men and boys and 14,380 women and girls) will be diagnosed this year.

Some people who are initially diagnosed with CUP will have their diagnosis changed when a primary site is identified later. As diagnostic clinical and pathologic testing improves and new diagnostic testing becomes available, the incidence of CUP may go down.

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 where the cancer is located, how much it has spread, the 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 Types of Treatment section of this guide.

It is important to remember that statistics on the survival rates for people with CUP are an estimate. The estimate comes from annual data based on the number of people with this cancer in the United States. Also, the estimate may not reflect the results of advancements in how CUP is diagnosed or treated from recent years. Talk with your doctor if you have any questions about this information. Learn more about understanding statistics.

Statistics adapted from the American Cancer Society’s publication, Cancer Facts & Figures 2022, and the ACS website. (All sources accessed January 2022.)

The next section in this guide is Risk Factors. It describes the factors that may increase the chance of developing CUP. Use the menu to choose a different section to read in this guide.