Examining The Family Tree: Discovering The Risks With Genetics And Cancer

We are just at the very beginning of our knowledge base. Genes are going to be identified that predispose or contribute to lung, prostate, skin and other cancers." — Bob Young, Ph.D.

The time was the mid 1990's. A 20-year veteran at the School of Medicine, Dr. Young already had the establishment of USC’s comprehensive prenatal/pediatrics genetic program to his credit. Then he shifted gears in his research and began looking at ovarian cancer. Around this same time on the national scene, cancer researchers announced the identification of BRCA1 and BRCA2, two inherited gene mutations that put women at increased risk of developing breast and ovarian cancer. Locally, Dr. Young began attending weekly breast cancer conferences at which cases were presented and treatment options discussed. He recalls his initial presence among the oncologists, radiologists, pathologists, and surgeons. “In the beginning they didn’t know who I was and I’d just keep my mouth shut. Then slowly I started asking, ‘Is there any family history of cancer in this situation?’”

Over time the physicians began asking for Dr. Young’s input at the breast cancer conferences. Another development occurred as well. He recalls, “Once oncologists in town realized that I was a geneticist who knew something about cancer, they started having their patients who were worried about their family history call me.” It wasn’t long before the demand for genetic counseling services was more than Dr. Young could handle. That’s when Karen Brooks, a genetic counselor in the Department of OB/GYN with a prenatal and pediatric background, shifted her focus to become the School of Medicine’s cancer genetics counselor.

Cancer Genetic Counseling

Karen Brooks estimates that half of her patients already have a cancer diagnosis. They’re looking to learn if their heredity increases the risk of other cancers in themselves or the development of cancer in close relatives. The other half are unaffected by cancer, but have a number of family members who are. They also want to ascertain the potential genetic impact. The first step Brooks takes is to create a pedigree or a family medical tree by compiling health histories of at least three generations of relatives. The task of piecing together the incidence of cancer in families can be a challenging one. “Sometimes people can get the information and sometimes they can’t,” said Brooks, who explains that written diagnostic records or pathology reports are preferred for the most accurate accounting. She also finds that, “some patients have done their detective work and come in with their mother’s medical records from 1965.”

The process continues with a cancer risk assessment, in which Brooks looks for a pattern of potentially related cancers, such as breast cancer and ovarian cancer or colon cancer and uterine cancer, which tend to run together in families. If such a pattern is established, patients may choose to undergo genetic testing. “I explore with patients their reasons for wanting the genetic testing done. Many people tell me that they want to know for their relatives’ sake – their children, siblings etc.,” Brooks said. The information revealed from the blood test may influence any number of decisions on how patients decide to address their health risks. “For example, someone with a colon cancer mutation may want to have more frequent colonoscopies and start them at an earlier age,” she said.

Genetic Mutation

When the presence of a BRCA gene mutation is established, it dramatically increases a woman’s likelihood of developing breast cancer. “We know that if you live to be 50, you have up to a 50 percent chance of getting the disease; if you live to be 70, you have up to a 70 percent chance. You could have a mammogram in January and develop the cancer in February; we just don’t know when you will get it,” explained Dr. Young. Armed with this information, some women start on a chemoprevention medication such as tamoxifen. Others elect to have a mastectomy as a preventive measure, known as a risk reduction mastectomy. “I seem to have more and more patients coming in who say, ‘Yes, I would consider having both my breasts removed if I have a mutated gene,’” Brooks said.

Uncovering a significant risk of cancer is not without significant emotional impact, and part of Brooks’ job is helping patients maneuver through that rocky terrain. “I encourage patients to bring a support person when they come in for test results, especially if it’s going to be an emotionally charged situation,” she said.

While the majority of Brooks’ patients (a total of 240 in 2003) are referred because of a family history of breast cancer, a small but growing number come to her because of colon cancer and other types of cancers. She and Dr. Young now attend a monthly gastrointestinal tumor board, and envision that referrals from colorectal surgeons and gastroenterologists will be on a steady increase. “We figure that there are about 160 patients a year with a colon cancer history in the Midlands that we’re not seeing right now,” said Dr. Young. He added, “We have come a tremendous way in educating physicians on the role of family history,” he said, which reflects in the growth of the Cancer Genetics Program.

Providing education on the role of genetics and cancer has been an important component of Dr. Young and Brooks’ work. A staple of presentations that Brooks makes to medical personnel and community groups is the 3-2-1 Principle. “If three individuals in a family are affected with the same or related malignancy, if two are first degree relatives (such as siblings or a parent and a child), and if one is diagnosed prior to age 50, then that family should minimally seek the advice of a genetic professional,” she explains to groups.

As cancer research continues, the Cancer Genetics Program is likely to continue to expand. “We are just at the very beginning of our knowledge base. Genes are going to be identified that predispose or contribute to lung, prostate, skin and other cancers. It’s inevitable,” Dr. Young said. For families with cancer in their family tree that could mean more access to information that could help safeguard the health of generations to come. “Our patients seem to be very proactive; they want to do something to help themselves and their families. It’s very inspiring,” Brooks said.

Reprinted from Connections newsletter, March 2004

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