Cancer Risk: What the Numbers Mean

You might wonder about your chances of developing cancer. News reports can make it sound as if every day something is found to dramatically raise your risk. Sorting through all the information and figuring out what’s valid can be tricky.

What is risk? When scientists talk about risk, they’re referring to a probability – the chance that something may occur but not a guarantee that it will.

How is risk expressed? Risk is generally divided into two categories, absolute risk and relative risk. Absolute risk refers to the actual numeric chance or probability of developing cancer during a specified time period. For example, within the year, within the next five years, by age 50, by age 70 or during the course of a lifetime. Relative risk gives you a comparison or ratio rather than an absolute value. It shows the strength of the relationship between a risk factor and a particular type of cancer by comparing the number of cancers in a group of people who have a particular trait with the number of cancers in a group of people who don’t have that trait.

Where do cancer risk statistics come from? Most information about cancer risk and risk factors comes from studies that focus on large, well-defined groups of people. Cancer researchers have identified many of the major environmental factors that contribute to cancer including smoking for lung cancer and sunlight for skin cancer.

How do cancer risk statistics relate to you? Risk statistics can be frustrating because they can’t tell you your risk of cancer. Studies may have found that men have a nearly 40% chance of developing cancer in their lifetimes but that doesn’t mean your risk is 40%.

Your individual risk is based on many different factors such as age and habits (including eating habits), family history of cancer and the environment in which you live. Talk with your doctor about your risk of cancer. He or she can review what elements in your life may increase your risk. You can then discuss what to do to help lower this risk.

Keep cancer risk statistics in perspective. You might hear a news report about a study that seems to indicate you may be at increased risk of a particular type of cancer. Don’t jump to conclusions based on this one report. Take a step back and think about what the risk really means. Scientists weigh the evidence of many research studies over time to better determine whether a finding is true. News reports, though, focus on each new study in isolation rather than as a part of an evolving picture. This can sometimes cause unnecessary alarm or confusion.

When you read or see a report about cancer risk statistics, pay attention to these details. A news report may say a certain activity increases the risk of cancer for a group of people. But who was being observed in the study? Pay attention to the ages of the people and their characteristics. For instance, some people are genetically predisposed to certain types of cancer. How many people were studied? In general, studies involving thousands of people are more accurate than are those that examine a small group of people. If you’re concerned about the risk talk to your doctor.

Behavioral Health Systems is the parent company of Safety First. BHS offers Mental Health and Substance Abuse benefits to employers along with Employee Assistance Programs.