Photography by Kevin A. Roberts
A woman in her twenties develops breast cancer. She opts for genetic testing to determine whether her illness is hereditary. She tests positive for a BRCA1 gene mutation, a genetic condition made famous by Angelina Jolie. But the story doesn’t end there.
Next, her siblings are tested. All come back positive. Then it’s their mother’s turn. Mom is negative, so they turn to Dad, who carries the mutation. He hasn’t spoken with his three sisters in decades, but he agrees to contact them. One of his sisters has dealt with breast cancer and knew about the mutation, but hadn’t told anyone. A second sister tests positive and has preventative surgery—a life saved. But the original patient dies, a tragedy that perhaps could have been prevented if the estranged aunt had disclosed her mutation earlier.
Who knew that genetic cancer testing was such a family affair? That’s why Suzanne Mahon, the first oncology nurse in Missouri to be certified in genetics, organizes charts by families, rather than by individuals, in her office at the SLU Cancer Center.
It’s also why she starts with a free 90-minute consultation. “That’s to find out what they know, what they want to know, to help them to understand what they’re getting into,” Mahon says. She’ll draw a picture of patients’ family trees, plotting which relatives have been affected by cancer, then explain their situations. It’s important that patients understand the possible outcomes—and are willing to share the results with their families. “You don’t have to have Thanksgiving dinner with them, but you owe them the phone call,’” she says.
Not all negative tests are necessarily good news. If you know your family has a specific mutation and you test negative for it, then you’re in the clear. But if the cause of your family’s cancer history isn’t known, a negative result might mean you still have a different hereditary risk factor and should increase screenings. She suggests genetic testing for anyone who gets cancer at an unusually early age, who has a family history of cancer, who’s a man with breast cancer, or who belongs to certain ethnic groups. An estimated 5 to 10 percent of cancers are hereditary; breast, colon, ovarian, uterine, and thyroid cancers are the most common to have a genetic link.
Within just three months of testing, 91 percent of Mahon’s patients have followed through on her recommendations, an impressive number when you consider that many of those suggestions include major elective surgery. If it all sounds like too much trouble, then know this: “We do change people’s lives,” Mahon says.
She remembers a woman who tested positive for Lynch syndrome, a genetic condition associated with colon cancer. After Mahon prescribed annual colonoscopies, the first test came back negative. But a year later, doctors found two serrated polyps, catching them early enough for treatment. The patient called Mahon with the news. “If I hadn’t known I had that mutation,” she said, “I wouldn’t have gotten my first colonoscopy until well after 50, and I’d be dead.”
