Unknown Primary: Statistics

Approved by the Cancer.Net Editorial Board, 03/2023

ON THIS PAGE: You will find information about the estimated number of people who will be 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, and no 2 people with cancer are the same. Use the menu to see other pages.

Every person is different, with different factors influencing their risk of being diagnosed with this cancer and the chance of recovery after a diagnosis. It is important to talk with your doctor about any questions you have around the general statistics provided below and what they may mean for you individually. The original sources for these statistics are provided at the bottom of this page.

How many people are diagnosed with CUP?

CUP is estimated to account for around 2% of all cancer diagnoses in the United States. This means about 32,590 people (16,810 men and boys and 15,780 women and girls) will be diagnosed in 2023.

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.

It is estimated that 48,160 deaths (26,130 men and 22,030 women) from CUP will occur in the United States in 2023.

What is the survival rate for CUP?

It is important to remember that statistics on the survival rates for people with CUP are only an estimate. They cannot tell an individual person if cancer will or will not shorten their life. Instead, these statistics describe trends in groups of people previously diagnosed with the same disease, including specific stages of the disease.

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.

The survival rates for CUP vary based on several factors. These include the subtype of cancer, tumor location, a person’s age and general health, and how well the treatment plan works.

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.

Experts measure survival rate statistics for CUP based on annual data. This means 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 (ACS) publication, Cancer Facts & Figures 2023, and the ACS website. (All sources accessed March 2023.)

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