Dispelling Myths about Inherited Cancer and Genetic Testing

A family history of cancer is certainly a common, uncontrollable risk factor. But most cancers aren't inherited.

Cancer is a genetic disease caused by abnormal changes over time to genes that control cell function, typically starting in a single cell (an acquired mutation) and often not linked to an inherited genetic mutation. In other words, most cancers happen by chance.

Only about 5 to 10 percent of cancers are due to an inherited genetic mutation, says Monique Lubaton, MGC, CGC, cancer genetic counselor at the Alvin & Lois Lapidus Cancer Institute at LifeBridge Health. Nonetheless, if you have a strong family history of cancer, genetic testing may be indicated for you. Patterns to look out for in a family are breast, ovarian, prostate or pancreatic cancers (especially if you are of Ashkenazi Jewish descent), as well as colon and uterine cancers.

Lubaton helps debunk myths about inherited cancers and genetic testing:

Myth: I tested negative for a mutation in BRCA1 and BRCA2, so I do not have a hereditary cancer syndrome.

It is estimated that one in 500 individuals in the general population has a BRCA1 or BRCA2 mutation, while approximately one in 40 in the Ashkenazi Jewish population (Central or Eastern European) carries a mutation in one of these two genes. While BRCA1/2 mutations are the most common cause of with hereditary breast or ovarian cancer, testing negative for those two does not mean there is no underlying hereditary cancer syndrome, Lubaton says. "There are a number of other genes that are associated with hereditary cancer syndromes," she says.

Myth: If I have an inherited genetic mutation, I will get cancer in my lifetime.

It is not a given that people with a hereditary cancer syndrome will actually develop cancer. Lubaton says that most hereditary cancer syndromes have "moderate to high" risk levels, but that "with guided management, those risks can be reduced."

Myth: A woman cannot get a genetic mutation from her father.

Almost all hereditary cancer syndrome mutations can be passed down by either gender, Lubaton says. Both men and women can be carriers of a BRCA1 or BRCA2 mutation, but inherited alterations in these genes make female carriers more susceptible to developing breast and ovarian cancers.

Myth:  I've already had cancer, so it doesn't matter whether or not I know if I have an inherited genetic mutation.

Individuals who are carriers of a hereditary cancer syndrome can be at increased risks for multiple primary cancers over their lifetime, hence why it's important to pursue genetic testing and learn about mutation status. "Also something important to know, there are now targeted therapies for individuals with genetic mutations," Lubaton says.

Myth: Genetic testing is expensive and not covered by medical insurance.

Lubaton insists that genetic testing has become much more affordable in recent years.

"I think a lot of people, when they think about [genetic testing], they think it is very, very expensive, and it did used to be very, very expensive. But fortunately, over time, and with better medical coverage and competition, the cost of genetic testing has been significantly reduced," Lubaton says, adding that testing is "well-covered" by insurance.

Other signs of hereditary cancer syndrome include:

• Cancer found at an early age (under 50)
• Three or more family members (on the same side of the family) with the same type of cancer
• One or more family members with multiple cancers
• Rare cancers like medullary thyroid cancer, paragangliomas and male breast cancer
• History of more than 10 colon polyps

Genetic counselors at the Alvin & Lois Lapidus Cancer Institute can review your personal and family history, explain hereditary cancer syndromes in greater detail, and discuss the benefits and limitations of genetic testing. For more information, call 410-601-4600. Referrals can be faxed to 410-601-8448.