Communicating Genetic Risk
Risk can be framed in a number of different ways, and risk communication should be tailored to the individual patient.
Types of Risk
Qualitative vs. Quantitative
Qualitative: Risk given in general risk categories (once family history and other risk factors have been assessed):
- High risk: individuals with a hereditary cancer syndrome
- Moderate/increased risk: those with personal or familial risk factors
- Average risk: those with few or no risk factors
Quantitative: risk given as fractions or percentages
Relative risk (RR) compares the likelihood that an individual or group with a risk factor, such as family history of cancer, will develop a health condition such as cancer, compared with (or relative to) an individual or group with a similar background without that risk factor. Relative risk should always be discussed in contrast to the comparison group.
- Example: According to the American Cancer Society, the RR of having colorectal cancer (CRC) when a first-degree relative (FDR) is diagnosed with CRC is 2.2. This means that an individual with a parent, sibling or child diagnosed with CRC is more than twice as likely to be diagnosed with CRC than an individual without that family history.
Absolute risk is the risk that an individual will develop a disease over a specific amount of time and is often expressed as lifetime risk. Most patients find absolute risks more meaningful than relative risks. It is important to remind patients that lifetime risk is not the same as the risk at a specific point in time.
- Example: An individual at average risk has a 5.5 percent lifetime risk of developing colorectal cancer by age 70. This means that approximately one in every 18 individuals will develop colorectal cancer by age 70.
Assessment of risk involves evaluation of both inherited and personal/environmental aspects of an individual’s health.
Points to Consider
- Use simple language.
- Provide risk information in at least two different ways. For example:
“Your risk of developing cancer is about one in 50 over the next 10 years. This is the same as saying your risk is about 2 percent over the next 10 years.”
- Graphs and diagrams are often helpful. Put risk in perspective. For example:
"Your chance of developing colon cancer is about 5 percent, but your chance of dying of colon cancer is far less, less than 1 percent.”
- When providing a lifetime risk, make sure to include the baseline risk for comparison. For example:
“The average woman’s lifetime risk of developing breast cancer is about 12 percent by age 80. Women with a BRCA1 mutation have an approximate lifetime risk of 60 to 85 percent.”
- Sometimes giving a qualitative risk (high, moderate or average) is sufficient and more meaningful to the patient.
- Consider life experiences when providing risk information to a patient. For example, individuals who have a relative with cancer or who have experienced rare or unusual events may interpret risk information differently.
Doctor: Mr. H, you told me that you don’t smoke or drink alcohol and have a healthy lifestyle. That’s great! Now tell me about your family history. Anyone in your family with a history of colon cancer?
Mr. H: Well, my dad had colon cancer at age 55, but he died of a heart attack in his late 70s. I can’t think of anyone else in the family.
Doctor: Ok. Well, based on your family history, your risk for colon cancer may be about double that of someone in the general population.
Mr. H: Wow, is that a lot? It sounds like a lot.
Doctor: Keep in mind that the “general population” includes everyone—those at high risk and low risk. The lifetime risk for colon cancer in the general population is 5 percent. And while your family history would suggest that your risk is higher than the general population, your lifestyle may help temper that risk some. It’s hard to put an exact number on an individual’s risk. The most important thing about understanding risk is using the information to improve and monitor your health. There are some risks you can control like your lifestyle factors—and you are already doing that. And some risks you can’t control, like your family history.
Mr. H: Ok, well, that doesn’t sound as bad. I may have some increased risk because of my family history, but I’m doing what I can to keep that risk as low as I can. So now what?
Doctor: Since you are already 49, and because you do have that family history, I would recommend we go ahead with a baseline colonoscopy now. The standard recommendation is to wait until age 50. When there’s a family history of colon cancer, sometimes we start colonoscopies a bit earlier.
Mr. H: Sounds good. Thanks doctor.
Lautenbach DM, Christensen KD, Sparks JA, and Green RC (2013): Communicating Genetic Risk Information for Common Disorders in the Era of Genomic Medicine. Annu Rev Genomics Hum Genet.
Research Advocacy Network (2014): Tutorial: Understanding Cancer Risk.
Originally developed through collaboration between the National Coalition for Health Professional Education in Genetics and the American Medical Association.