Unknown Primary: Risk Factors

Approved by the Cancer.Net Editorial Board, 03/2014

ON THIS PAGE: You will find out more about the factors that increase the chance of developing this type of cancer. To see other pages, use the menu on the side of your screen.

A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices. 

Since CUP can be almost any type of primary cancer, the risk factors for all types of cancer are risk factors for CUP. The following factors can raise a person’s risk of developing CUP:

  • Age. The average age of a person diagnosed with CUP is 60.
  • Tobacco use, including cigarette smoking, chewing tobacco, and cigar smoking
  • Sun exposure
  • Exposure to large amounts of radiation
  • Exposure to chemicals in some manufacturing industries
  • Poor nutrition
  • Lack of exercise
  • Family history. If more than one brother, sister, parent, or grandparent has been diagnosed with breast, ovarian, or colorectal cancer, the risk of cancer increases.

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