P. Kelly Marcom, MD, director of the Duke Hereditary Cancer Clinic, answers questions about hereditary cancers.

Most people who get cancer have not inherited it from their parents. However, approximately 5 to 10 percent of cancers are due to an inherited mutated -- or altered -- gene.

At the Duke Hereditary Cancer Clinic, doctors and genetic counselors work with patients to determine their likelihood of developing certain cancers and to discuss treatment options, if necessary.

Since the Hereditary Cancer Clinic opened in 1999, more than 3,000 patient evaluations have been conducted. Many of these patients have had genetic testing to determine whether they have an inherited mutation.

We spoke with P. Kelly Marcom, MD, director of the Duke Hereditary Cancer Clinic and assistant professor of medicine, about the clinic and hereditary cancers.

Who comes to the clinic?

People who visit our clinic generally fall into two categories. The first group is comprised of patients who have already been diagnosed with cancer. We perform the genetic test at that time because knowing a person’s genetic make-up provides his or her physician additional information that may help determine what treatment will be most effective and what measures should be used to prevent future recurrence.

The second group is comprised of people who want to determine their likelihood of developing certain cancers, usually because their relatives have already been diagnosed with cancer.

Most frequently, the Hereditary Cancer Clinic tests for predisposition to breast, colon, and ovarian cancer, although testing related to rarer forms of cancer is also done. Duke can test for any cancers for which a test has been developed. The clinic monitors new developments in cancer genetics and continuously evaluates new testing procedures.

Much of the testing and counseling takes place at our clinic at Duke with genetic counselors Robin King, MS, and Tracey Leedom, MS, and Adam Buchanan, MPH, MS, who also provides genetic counseling and testing to patients in several hospitals throughout North Carolina that are affiliated with the Duke Oncology Network. Many of these hospitals are located in rural communities where this type of service was not previously available.

Does health insurance cover genetic testing?

Reimbursement for genetic testing is evolving. Many insurance companies are now covering genetic testing. We work with the patients, their insurance carriers, and the genetic testing laboratories to facilitate testing coverage.

Describe the genetic testing process.

At our clinic, the patient first meets with a certified genetic counselor and discusses his or her medical history as well as their family’s medical history, and the pros and cons of genetic testing.

Those who have not been diagnosed with cancer will also discuss the risk of getting cancer. Even if a mutated gene is discovered, it does not guarantee that the patient will develop cancer. It does indicate that the patient is more likely than the average person to develop particular cancers.

Patients found to have a mutation must weigh the risks and benefits of their options and work with the physician and genetic counselor to determine the best course of action.

Some situations may warrant careful monitoring. In others, patients may elect to have preventative surgery.

Patients who receive negative genetic test results (no mutation found) must understand that they are not guaranteed a cancer-free life. Since most forms of cancer are not inherited, a person who tests negative for a mutation could still develop cancer later in life.

What about privacy and discrimination issues?

A genetic counselor talks with each patient about privacy issues before any tests are performed. Insurance companies have the right to see the results of the tests if the company covered the cost of the tests.

However, federal law prevents health insurance companies from denying coverage or raising rates due to the results of genetic tests. This law also prevents employers from using genetic testing results to make decisions about who to hire or promote. Additionally, North Carolina and many other states have laws that provide similar protection against discrimination in health insurance and employment.