Stages and types of cancer of unknown primary

The stage of a cancer tells you how big it is and whether it has spread. With cancer of unknown primary (CUP), doctors can't find out where the cancer started (the primary cancer). So there isn't a staging system for CUP.

The type tells which type of cell the cancer started from. In CUP, there are 5 main types. 

Stages of cancer of unknown primary

There is no staging system for cancer of unknown primary (CUP). Find out why doctors can't accurately stage this cancer type. 

Types of cancer of unknown primary

CUP can be grouped according to the type of cell they start from. Doctors can find out which type of cell the cancer started in by looking at a sample of the tumour under the microscope.

Last reviewed: 
19 May 2021
Next review due: 
19 May 2024
Coronavirus and cancer

We know it’s a worrying time for people with cancer, we have information to help.

Read our information about coronavirus and cancer