Adoption and cancer risk: Should you get genetic testing?

A family history of cancer could put you at higher risk of developing that disease one day. Depending on what type of cancer is involved, it could also mean that you need more frequent screenings or genetic testing for inherited mutations.

But what if you were adopted as a child? How can you best assess your cancer risk as an adult? Are there any steps you can take to reduce your cancer risk? We spoke with Therese Bevers M.D., director of MD Anderson’s Lyda Hill Cancer Prevention Center. Here’s what she recommends.

Use what you know to make initial decisions

Open adoptions — in which one or both biological parents elect to stay in touch with their child and adoptive families — are much more common now than they used to be. 

But if that’s not the case for you, use the details you do know about yourself and your birth parents to make decisions, such as when to start getting recommended cancer screenings or if you should seek out genetic testing.

• Adoptees with Black heritage, for instance, may need more frequent colorectal cancer screenings, due to higher rates of the disease in that community. 
• Adoptees of Ashkenazi Jewish descent, meanwhile, might want to be tested for the three BRCA gene variants common among that population, as they can increase your risk of breast cancer and ovarian cancer.

If you were part of an open adoption and your biological parents are still living, you may be able to ask them directly for details about your blood relatives’ health histories. The one scenario in which you want to tread lightly is in contacting any newly discovered blood relatives that you’ve identified through popular DNA-testing and matching services.

“Finding out you have some half-siblings may be very exciting for you,” notes Bevers, “but it could also open up a can of worms on the other side. Maybe your shared birth mother never told her husband or kids about you, so neither he nor any of your half-siblings even know you exist.” 

Use what you learn to make adjustments

Some adoptees have blood relatives closer at hand because they were adopted with their siblings by the same people, or they were adopted by extended family members, such as a paternal aunt and uncle or a maternal grandmother. If that’s the case for you, you may already be aware of your family’s cancer history. But if you’re not, ask.  

“Any time you can learn more about potential health challenges from blood relatives, it may benefit you,” Bevers explains. “But even if you can’t, don’t worry. Only 5% to 10% of cancers are due to a genetic predisposition. The vast majority are not.”

Reduce your cancer risk through healthy lifestyle choices

Since most cancers are not hereditary, Bevers notes that it’s far more important to focus on other cancer risk factors that can be reduced through lifestyle changes.

• Avoid tobacco: And if you smoke or vape, quit now. Medication and counseling are the best ways to do it. You can call 1-800-784-8669 or text QUIT to 47848. Patients and caregivers at MD Anderson may also join our Tobacco Research and Treatment Program.  
• Limit alcohol: Alcohol consumption is linked to several cancers, including breast, colorectal and liver. For cancer prevention, it’s best not to drink alcohol. But women who choose to drink should have no more than one drink a day, and men no more than two drinks a day.
• Eat a plant-based diet: Fill two-thirds of your plate at every meal with vegetables, fruits, whole grains and beans. Fill the remaining third with meat, fish or animal products like dairy and eggs.  
• Maintain a healthy body weight: Carrying excess weight increases your risk for many types of cancer, including breast, colon, endometrial and liver.
• Get physically active: Cardiovascular exercise and strength training help the body regulate hormones, digest food and maintain a healthy weight.
• Protect your skin: Protect your skin from harmful UV radiation by using SPF 30 sunscreen or higher, wearing protective clothing outdoors and seeking shade when the sun’s rays are at their strongest, between 10 a.m. and 4 p.m.
• Consider an HPV vaccine: You can protect yourself against multiple cancers — including throat, anal, cervical, penile and vulvar — by getting vaccinated against the human papillomavirus (HPV). Everyone ages 9-26 should get it, but people ages 27-45 may still benefit from it. Talk to your doctor to see if the HPV vaccine series is right for you.

Most people don’t need genetic testing

Once you’ve taken steps to reduce your cancer risk in as many areas as you can, is there any benefit to seeking out genetic testing if you were adopted?

Since 90% to 95% of all cancers are not hereditary, Bevers says no. 

“If somebody knows for sure that they have a family history of cancer, we might recommend it,” she explains. “But since most people don’t, in this scenario, a lack of knowledge is the same thing as having none. So, we really wouldn’t have any reason to test you.”

Instead, she talks adopted patients through other possible scenarios that could indicate they’re at higher risk of cancer. 

“I’ll ask questions like ‘Have you ever had a breast biopsy or had a high-risk lump removed? Have you ever had a colonoscopy and had precancerous polyps removed?’” she says. “Things like that can tell me just as much — if not more — about your risk level than any family history.”

Make an appointment at the Lyda Hill Cancer Prevention Center online or by calling 1-855-496-1017.