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Family tree includes a genetic time bomb

When a woman learns her rare cancer is hereditary, relatives must get tested and evaluate their distressing options.

January 20, 2008|Judith Graham | Chicago Tribune

Five months before dying of a rare form of stomach cancer, Sandra McNamara uncovered a devastating family legacy.

Her illness was closely linked to a genetic mutation. She had it, and that meant her three sisters and their children might have it too.

McNamara picked up the phone and started calling relatives in Chicago, Boston and Denver. You need to know: This cancer is hereditary, she said. Get tested.

The disclosure threw the family into turmoil as relatives evaluated their choices, including whether to have their stomachs surgically removed as a preventive measure.

Few families have grappled as dramatically or extensively with their genetic heritage as McNamara's, though tests for other mutations, such as those linked to breast cancer, have been available for years. Many more people will find themselves in similarly wrenching situations in the years ahead as genetic tests proliferate and scientists learn more about the genetic basis of disease.

With advance knowledge of their potential destinies, people will ponder whether to share the information with parents, siblings and children and how best to respond to worrisome risks.

The story of McNamara's family provides a glimpse of how complicated and life-changing these genetic revelations promise to be.

The threat in their case was hereditary diffuse gastric cancer, which hides in the stomach and forms small tumors scattered like needles in a haystack. That means it's difficult to catch through screening, the way women try to find early breast cancer with a mammogram. By the time symptoms occur, the disease has typically reached a serious stage.

For people with the mutation, however, the alternative to screening is terrifying. The only current option to prevent this cancer is removal of the entire stomach -- an extraordinarily radical step, although it could save their lives.

Ultimately, McNamara's family opted for genetic testing. Six female relatives learned they carried the stomach cancer mutation. Four of those six pursued stomach surgery; two opted for regular screenings. All are still confronting the consequences of their decisions.

Five sisters

McNamara was the second of five sisters, a dignified, religious woman who loved to paint and who had worked for years in human resources at Walgreen's before retiring in Glenview, Ill.

The sisters knew there was cancer in the family. But when McNamara's father died of stomach cancer in 1961, it was an illness people didn't discuss. Fourteen years later, when one of her sisters died of the same disease, it seemed like a fluke.

In late 2004, McNamara was diagnosed with breast cancer. While still on chemotherapy, McNamara returned to Evanston Hospital with abdominal pains. Doctors discovered advanced stomach cancer.

Scott Weissman, a genetics counselor at the hospital, had a hunch McNamara might have hereditary diffuse gastric cancer, a rare condition identified only seven years earlier.

About 100 families of various ethnicities have been identified with this disease worldwide, said Dr. David Huntsman, a genetic pathologist at the British Columbia Cancer Agency in Canada.

Testing would show McNamara carried a telltale genetic mutation linked with the cancer. The mutation -- a coding error in the genetic software that resides in cells -- lies on the CDH1 gene, which is responsible for making a protein that binds cells together.

The implications were clear: McNamara's father probably had the mutation, as did the daughter who died.

For the surviving sisters, this was a potentially deadly inheritance: 70% of people with the mutation develop hereditary diffuse gastric cancer by age 75, research shows. The only treatment is stomach-removal surgery, sometimes accompanied by chemotherapy and radiation.

Outcomes are dismal. According to Dr. Jennifer Obel, an Evanston Hospital oncologist, just 10% of patients with diffuse gastric cancer are alive five years after diagnosis.

Opting for test

Telling her family about the genetic mutation would be McNamara's final gift -- an effort to save them from the suffering that awaited her.

Her three surviving sisters took the news in stride, aided by a large dose of denial. Still, all decided to get tested.

Linda Green, then 69 and living in Batavia, Ill., was sure she was OK -- but if, God forbid, there was a problem, she'd want her three kids to know.

In Denver, Judy Bulow, then 59, also was convinced she was safe. But she too wanted to know.

"I was hoping I wouldn't have it; that I'd be fine," said Martha Lassy, who lives in Geneva, Ill.

McNamara left it up to her sisters to disclose the medical discovery to their families. But she reached out to three members of the next generation: the children of her fourth sister, Bonnie Gosse, who had died of stomach cancer 30 years earlier, at age 33.

The news was overwhelming. "It brought back all the stuff from my childhood, when Mom died," said Julie Gosse, who grew up in Elgin, Ill., and now lives in Denver.

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