Family History Important for Predicting Cancer Risk

ISLAMABAD: Do you know your family health history? If you don’t, experts say you should. Knowing whether your relatives have had illnesses like cancer, diabetes, or heart disease can help predict your risk of developing the same diseases.

"Family history is an important risk factor for most cancers, including breast, colon, prostate, and ovarian cancers," said Heather Spencer Feigelson, PhD, MPH, a senior epidemiologist at the American Cancer Society who specializes in genetics. "Keeping an accurate record of family medical history, just like keeping an accurate record of current prescription medications, can be an important tool to help you and your doctor discuss the most important prevention strategies."

Most Americans, though, don’t keep good track of their family medical history. Researchers from the Centers for Disease Control and Prevention recently found that just 30% of people actively collect this information, even though more than 96% think it’s important for their own health. The findings, published in Morbidity and Mortality Weekly Report (Vol. 53, No.44: 1044-1047), were based on a 2004 survey of more than 4,000 US residents age 18 or older.

For instance, a woman with a family history of breast cancer might decide to get more frequent mammograms, or to add other screening tests like ultrasounds or MRIs (magnetic resonance imaging) to her regular mammogram schedule. Taking tamoxifen to prevent breast cancer might also be appropriate for some women at high risk. Men with a strong family history of prostate cancer might decide to start PSA testing at a younger age than normally recommended. Likewise, people with colon cancer in the family might begin screening earlier or have more frequent exams.

Family medical history may also influence lifestyle choices, Feigelson said.

"For people with a family history of cancer, it may be especially important that they don’t smoke, eat a diet rich in fruits and vegetables, and maintain a healthy body weight, because we know these things contribute to many types of cancer and other chronic diseases," she explained.

One thing to keep in mind: Family history comes from both your mother and your father. It’s important to know the medical histories on both sides of the family.

A thorough family history can also flag families who may be appropriate candidates for genetic counseling and testing to look for gene mutations that might cause cancer. Genetic cancers tend to strike people at younger ages, Feigelson said. If a family has several members who got the same type of cancer at a younger age than would normally be expected, it might signal a genetic predisposition that could be inherited.

"It’s not that unusual to have two women [in one family] who have had postmenopausal breast cancer because breast cancer is so common," Feigelson said. "That doesn’t necessarily suggest a strong genetic component."

A genetic counselor can help families with a strong cancer history decide whether testing is appropriate and explain what the test results may mean and what options the family may have once results are known.

But it’s important to remember that only a small proportion of cancers can be traced back to a single, inherited mutation. Most cancers, in fact, occur in people with no family history of the disease at all. For this reason, experts recommend following cancer screening guidelines even if you have no family members who have had the disease.