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Cancer of unknown primary

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Risk factors for cancer of unknown primary

A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors, but it is very hard to know what the specific risks are for cancer of unknown primary (CUP). This is because CUP is cancer that had already spread before it was found, but doctors don’t know where it started in the body. So CUP may have the same risk factors as different types of cancer.

Like many types of cancer, CUP most often affects older people. It is usually diagnosed in people who are around the age of 60.


Smoking may be a risk factor for CUP. In many cases doctors find out that CUP started as cancer of the lung, pancreas, kidney, esophagus or head and neck. Smoking is a risk factor for these types of cancer.


Diet, lack of physical activity and being overweight or obesemay affect your risk for CUP. This is because CUP can start as colorectal, stomach or ovarian cancer. Eating certain foods, not getting enough exercise or being overweight or obese can increase your risk for these types of cancer.

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about risks.


Parker Murchison My favourite thing about Camp Goodtime is being able to hang out with other kids who have survived cancer. They know what is going on in your life and can help you get through it.

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Facing the financial burden of cancer

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The Canadian Cancer Society provides helpful information about government income programs, financial resources and other resources available to families struggling to make sense of the personal financial burden they face.

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