Cancer risk: What do the numbers mean?

Cancer risk is often used to describe the chance that a person will get cancer or the chance that the cancer will come back. Researchers and doctors use these risks to reduce cancer risk through lifestyle, nutrition, and exercise recommendations.

When scientists talk about risk, they are referring to a probability, which is the chance that something might happen but there is no guarantee that it will definitely happen. For example, if you toss a coin, there is one of two chances of 50% heads and 50% tails.
Risk estimates for cancer and other diseases are determined by studying very large numbers of participants. Researchers focus on the probability that any person or type of person will develop the disease over a given period of time. In addition, scientists also looked at traits or behaviors that were associated with an increased or decreased risk of a certain disease.

2.1 Absolute risk Absolute risk refers to the actual chance or probability of developing cancer over a specified period of time, for example, within a year or within next five years, at age 50 or 70, or throughout life.
One type of absolute risk is lifetime risk, which is the probability that an individual will develop cancer during their lifetime. For example, an American man's absolute lifetime risk of developing prostate cancer is about 11%. In other words, about 11 out of every 100 men will develop prostate cancer. This also means that 89 of the remaining 100 men will not develop prostate cancer.
Lifetime risk is not the risk that a person will get cancer in the next year or the next five years. An individual's cancer risk has a lot to do with other factors, such as age. For example, a woman's lifetime risk of colon and rectal cancer is just over 4%, or about 42 out of 1,000 women. But the risk of these women getting colon and rectal cancer before the age of 50 is 0.3%, or about 3 in 1,000 women will get it.

2.2 Relative risk Relative risk gives you a comparison or ratio, not 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 with a distinctive feature with the number of cancers in a group of people without. that feature.
For example, compare the relative lung cancer risk for smokers with the relative lung cancer risk in a group of non-smokers with lung cancer. You might hear relative risk expressed like this: The risk of lung cancer for smokers is 25 times greater than the risk for non-smokers. So the risk of lung cancer for a smoker is 25.
Relative risk is also given as a percentage. For example, the risk of lung cancer for smokers is 2,500% higher than for non-smokers.
When you hear about relative risk, there is no upper limit to the percentage increase in risk. Most people think that 100% is the highest possible risk, but that's not true in this case.
100% relative risk means your risk is twice as high as someone without that risk factor. A 200% relative risk means you are three times more likely to develop that condition.

Most information about people at cancer risk and risk factors comes from studies that focus on large groups of participants. Cancer researchers have identified many environmental factors that cause cancer, such as smoking causing lung cancer and sunlight causing skin cancer.
Many studies on cancer risk factors are based on observational methods. In these studies, researchers followed a group of people for several years without changing their lives or providing special treatment. This could help scientists figure out who develops the disease and what these people have in common and how they differ from people without the disease.
Risk statistics can be frustrating because they can't tell you your cancer risk. Studies may have found that men have an almost 40% chance of developing cancer in their lifetime, but that doesn't mean your risk is 40%. An individual's specific risk is based on a variety of factors, such as age and habits (such as eating habits), family history of cancer, and living environment.
In addition, combinations of risk factors or interacting risk factors may not be the same for everyone. Cancer is personal. If two people have the same age, sex, race, socioeconomic status, and lifestyle, their chances of getting the disease are still different. Risk statistics are useful in general advice such as "regular exercise reduces the risk of chronic diseases, such as cancer". But regular exercise will not guarantee that you will not get cancer.

You may hear a news report about research that suggests you may be at risk for a particular type of cancer. However, do not jump to conclusions based on this one report, think carefully about what the risks really mean.
Observational studies are not perfect. Scientists weigh the evidence of many long-term studies to better determine whether a finding is true. Even so, news reports only focus on individual studies, rather than looking at many different studies. This can sometimes cause unnecessary misunderstandings.
When you read or view a report on cancer risk statistics, pay attention to the following details:
Who are the study subjects? A news report may say that a certain behavior increases the risk of cancer for a group of people. But who are the subjects in the study? Pay attention to the age of the participants and their characteristics. How many people were studied? In general, studies involving thousands of people are more accurate than studies involving only a small number of people. Have similar studies been done? The findings of one study are more reliable if the results are similar to those of other study groups. The news focuses on alarming statistics, such as a 300% increase in risk, but doesn't give you any other useful information in this study. If you are concerned about the risk, get more information and talk to your doctor.

Currently, Vinmec International General Hospital is implementing a package of Cancer Screening - A measure to help check and screen cancer at an early stage based on cancer risk factors in daily life.
Any questions that need to be answered by a specialist doctor as well as customers wishing to examine and treat at Vinmec International General Hospital, you can contact Vinmec Health System nationwide or register online HERE.
Source of article reference: mayoclinic.org.
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