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Cancer of Unknown Primary: Risk Factors

What is a risk factor?

A risk factor is anything that may increase your chance of having a disease. Risk factors for a certain type of cancer might include smoking, diet, family history, or many other things. The exact cause of someone’s cancer may not be known. But risk factors can make it more likely for a person to have cancer.

Man smoking on front porch.

Things you should know about risk factors for cancer:

  • Risk factors can increase a person's risk, but they do not always cause the disease.

  • Some people with 1 or more risk factors never develop cancer. Other people with cancer have no risk factors.

  • Some risk factors are very well known. But there's ongoing research about risk factors for many types of cancer.

Some risk factors, such as family history and age, may not be in your control. But others like diet, sun exposure, weight, and tobacco use are things that you can change. Knowing cancer risk factors can help you make choices that might help lower your overall cancer risk.

Who is at risk for cancer of unknown primary?

Almost any type of primary cancer can be a source for cancer of unknown primary (CUP) origin. It makes sense then the risk factors for most types of cancers are also risk factors for CUP. Because healthcare providers don’t know the why, how, or where of cancer of unknown primary origin (CUP), it’s hard to identify specific risk factors for it. Still, there are certain kinds of cancer that are more likely linked to CUP.

For instance, experts know that cigarette smoking is an important risk factor for many kinds of cancer that could lead to CUP. This also includes other forms of tobacco use like chewing tobacco and cigar smoking.

Age increases the risk for CUP. The incidence of CUP is highest in people between ages 60 and 75.

Certain diets and being overweight or obese have been linked to cancers of the stomach, colon, or rectum. These are all possible sources of CUP.

Melanoma, a type of skin cancer, could be linked to CUP.

Also, a certain family cancer history may be a risk factor. If more than one close relative, such as a grandparent, parent, or sibling, has been diagnosed with colorectal, ovarian, or breast cancer, you may have a higher risk of cancer. If you have a relative who has or had CUP, your risk for it is higher. Having a relative with CUP also increases your risk for lung, colon, and pancreatic cancers.

To lower your risk for cancer, including CUP:

  • Don’t smoke or use any form of tobacco. If you do, get help to quit.

  • Follow a healthy diet. Eat more fruits and vegetables.

  • Get to or stay at a healthy weight. Ask your healthcare provider for help.

  • Get regular exercise.

  • Use broad-spectrum sunscreen with SPF 30 or higher.

  • Follow safety precautions to limit your exposure to chemicals at home and at work.

What are your risk factors?

Talk with your healthcare provider about your cancer risk factors. They can tell you how to help lower your risk.

Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Susan K. Dempsey-Walls APRN
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 8/1/2023
© 2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.