Working the odds

In between, Niendorf, a genetic counselor at Massachusetts General Hospital, discusses their family history, their fears, and whether a test could help them decide how to cope with their cancer risks.

One recent day, a woman decided she wasn't ready to hear her chances of contracting cancer. A man with a family history of breast cancer opted to learn his odds of getting the disease. Another woman who'd just won a battle with breast cancer said she didn't want her genes tested. It fell to Niendorf to tell the woman that her genes might put her at risk for getting it again.

"The general rule of thumb is to allow them the opportunity to talk, to talk about their fears and concerns," said Niendorf, 32. "You're there to support them."

Genetic counseling, a small but rapidly growing field, promises to be a mainstay of 21st-century health care.

A decade ago, doctors only knew of a handful of disease-linked genes, like those for hemophilia, sickle-cell anemia and Huntington's disease. Now, new disease genes are discovered virtually weekly, and more than 1,000 genes have been tied to diseases. Cancer genetics is particularly booming, with more than 50 linked genes identified. And the number of tests will only increase as researchers continue deciphering the nearly 30,000 human genes in the genome.

"We're going to get to the point that every single physician will have a genetic disease that they deal with," said Dr. Sapna Syngal, the Dana-Farber Cancer Institute's director of gastrointestinal cancer prevention. "Every field, not only cancer, is going to deal with genetic disease. . . . We'll need more trained counselors to deal with it."

But genetic tests don't offer black-and-white answers. Rather, patients typically find out they have a partial chance of developing a disease -- odds of 40 percent, 30 percent, sometimes lower.

They then must decide: Should they get a hysterectomy to avoid a 40 percent chance of ovarian cancer, or a double mastectomy if the odds of getting breast cancer are 20 percent? With such vague odds, the decision can be wrenching. Frequently, patients opt to skip genetic testing altogether, even if they have a family history of a disease. They just don't want to know.

Helping them unravel all this falls to Niendorf and her colleagues.

"It's a frustration for all of us, that we have to sometimes just give percentages instead of absolute answers," Niendorf said. "But, as you talk through it, I think people realize having that knowledge is useful even if you can't tell people if or when they will get cancer."

In many cases, knowing about genetic risk does not point the way to treatments: Patients may balk at invasive preventive therapies when there is only a chance of developing cancer.

But often, knowing about genetic risk can lead patients to eat healthier, exercise more and seek regular screening to catch cancers early, when they may be more treatable. And they can warn loved ones about faulty genes possibly passed throughout the family tree.

In Boston, only the major hospitals have genetic-counseling staffs. But suburban satellite clinics will soon open to meet demand, private corporations will offer counseling, and smaller hospitals will hire their own counselors, gene testing experts said. The simple blood tests that can be analyzed for genetic mutations cost anywhere from $100 to $2,000, depending on the disease being tested.

Niendorf, who has a master's degree in genetic counseling from the University of Wisconsin, became interested in genes early, at age 8, when her newborn brother, Michael, was diagnosed with a rare genetic disorder and died within days of his birth. Her family still has the genetic counseling letter informing them they needed to be tested, too. All came up negative.

"Through this experience, I realized how valuable the work could be," she said.

Niendorf's training mixed biology with psychology, though the latter dominates most counseling sessions.

"People get mad or they cry or they're silent," Niendorf said. "Everybody's different; everybody expresses themselves differently."

Cases typically involve patients and their family members. Sick patients with a cancer that has been linked to a gene often seek testing to determine whether other family members are at risk and should be tested. And family members of patients, or those with a disease in their family tree, are often referred for testing by physicians.

With research on gene-based disease constantly expanding, especially in cancer medicine, Niendorf said she finds herself increasingly reviewing medical journals or attending scientific seminars to keep up.

Some days it seems like alphabet soup. There's BRCA, the breast cancer gene, and MLH, which is linked to colon cancer and PNS, which causes brain and nervous system cancers. Just this month, MYH, a colon cancer gene, was added to the list of genes about which Niendorf must be prepared to talk to her patients.

The gene mutation was linked this summer to colon cancer, and seems to pose a risk only if the mutation is inherited from both the mother and the father, but the research is still inconclusive.

Mass. General's genetic counselors haven't seen anyone with a double MYH mutations yet, but if they do, they'll recommend regular colonoscopies. The science isn't clear enough to point to a more-radical response, such as removing portions of the intestine.

Breast cancer tests dominate most of Niendorf's caseload. It has relatively clear risks and the treatment -- a double-mastectomy for those at highest risk -- is distasteful, but effective at preventing the disease.

One of Niendorf's recent patients, 25-year-old Nicole Ruby of Brighton, was already sick from intestinal tumors, bleeding and cramping when she arrived for counseling. She opted to skip the test that would tell her whether a gene mutation was the likely culprit behind her cancer -- and therefore whether she stands a chance of getting colon cancer again.

"I was sick. Knowing about my genetic risk wouldn't have helped at that point," she said. Her tumor-blanketed large intestine was removed. But before Ruby has children, she will have to face the issue again.

"It will play a part in my future, if and when I decide to have children," she said. "I have to know if they might inherit this."

For more information about genetic testing, see the website of the human genome project at www.ornl.gov/sci/techresources/Human--Genome/medicine/genetest.shtml or a federally funded site, which provides a directory of places to get genetic screening, www.geneclinics.org/servlet/access?id=8888891&

key=Ao9CMBuF-vNTM&gry=&fcn=y&fw=RurO&

filename=/clinicsearch/searchclinic.html.

Raja Mishra can be reached at rmishra@globe.com.