You may have heard that a family history of cancer puts you at greater risk for the disease. But does that include all cancers? Should you consider genetic cancer testing?
Genetic testing examines how genes are passed from one generation to the next. Genes affect everything from physical traits, like hair or eye color, to your likelihood of developing diseases like cancer.
While only about 5 to 10 percent of all cancers are caused by an inherited predisposition due to genetic mutations, according to the American Cancer Society, there are some cancers — especially gynecologic cancers — that tend to run in families. According to Dr. Susan Modesitt, the director of the high-risk breast and ovarian cancer clinic at UVA, this includes ovarian, fallopian tube, breast and endometrial cancers caused by mutations in the BRCA1, BRCA2 and Lynch syndrome genes, among others.
“When you knock out one of the tumor suppressor genes (like BRCA or Lynch genes), you’re born with a defect in the DNA repair mechanism in every cell of your body,” says Dr. Modesitt. “Then it doesn’t take nearly as much of an insult to knock out another gene that then predisposes that cell to develop cancer.”
Who Is Genetic Cancer Testing Recommended For?
It’s important to consider family and personal history to determine whether genetic cancer screening is right for you. This includes:
- Personal history of a cancer such as breast, ovarian, endometrial or other cancers potentially associated with an inherited disorder
- Family history of a cancer potentially associated with an inherited disorder
- Multiple generations affected by cancer linked to a genetic mutation, such as breast, ovarian and endometrial
- Early age of cancer diagnosis
- Ethnicity, such as Eastern or Central European Jewish ancestry, French Canadians and Icelanders, who tend to have a higher rate of BRCA mutations, according to the American Congress of Obstetricians and Gynecologists
Don’t forget to consider both sides of your family, since you inherit genes from both your mother and father. While your father may not present with breast or ovarian cancer, that doesn’t mean he may not be a carrier of the gene.
Dr. Modesitt says that ideally, doctors would start genetic testing with the person who has cancer to get a full genetic picture before the rest of the family gets tested.
What Do the Results of Genetic Cancer Testing Mean?
Genetic testing can give you more information than you expect. “Any of these big-name genetic mutations can have huge impact in terms of what your cancer risks are and also subsequently on what we should be doing in terms of cancer screening and, more important, cancer risk reduction,” says Dr. Modesitt.
If you test positive for a genetic mutation, it means you have a higher cancer risk but it doesn’t guarantee you’ll develop that disease. “You may have a mutation, but not everyone with a BRCA mutation will get breast or ovarian cancer. There are other things that help or don’t help — smoking, alcohol, exercise, being overweight. All of these things also play into whether you’re going to get cancer or not,” says Dr. Modesitt.
If you test negative for a known genetic mutation, it doesn’t fully clear you or the rest of the family, either. “We all have a baseline population risk for cancer, even if you don’t carry one of the big cancer causing genes,” says Dr. Modesitt. Plus, scientists don’t know every cancer-related genetic mutation; there are still many yet to be discovered.
If you’re concerned about your hereditary risk for cancer, talk to your doctor to discuss if testing is right for you.
Meet with a genetic counselor at UVA Cancer Center to discuss your history and risk.Learn More