Gene test helps some breast-cancer patients ditch chemo

Many women with early stage breast cancer can safely forgo chemotherapy thanks to a gene test that effectively predicts whether the disease will return.

Each year more than 100,000 women in the United States are diagnosed with breast cancer. Conventional treatment includes surgery to remove the tumor, and a combination of hormone therapy, and chemotherapy. Some experts believe this plan has helped reduce breast cancer deaths by more than one-third over the past 25 years. But many early stage breast cancer patients endure the high cost and harsh side effects of chemotherapy without much benefit. Doctors often agree but struggle to quantify the risk involved in opting out of chemo.

The genomic diagnostic breast cancer test, Oncotype DX, places a number (1-100) on that risk—the likelihood cancer will return—but how accurate is it?

To answer that question, the National Cancer Institute sponsored a study in which researchers enrolled 10,253 women with the most common types of early stage breast cancer. The study assigned women treatments based on their Oncotype DX scores and is currently tracking recurrence rates. The preliminary results for patients with a low Oncotype DX score (0-10) proved so compelling researchers opted to share the information this month in preliminary results published in TheNew England Journal of Medicine. Patients with an extremely low Oncotype DX score had less than 1 percent chance of cancer recurring within the next five years.

“You can’t do better than that,” said the study leader, Dr. Joseph Sparano of Montefiore Medical Center in New York. “Chemotherapy doesn’t reduce the chance of recurrence beyond 5 years.”

An independent expert, Dr. Clifford Hudis of New York’s Memorial Sloan Kettering Cancer Center, agreed.

“There is really no chance that chemotherapy could make that number better,” he said. Using the gene test “lets us focus our chemotherapy more on the higher risk patients who do benefit.”

A quantitative risk assessment tool such as the Oncotype DX test could offer a change in treatment plans that benefits thousands of patients.

“To date, more than 170,000 breast cancer patients have changed their treatment decision based the Oncotype DX test,” said Steven Shak, chief scientific officer for Genomic Health, the company that has sold the test since 2004. Medicare and many insurers cover the $4,175 cost.

Lynda Neff, a 61-year-old office manager for a plumbing company, said after doctors diagnosed her with breast cancer in 2007, she planned on a double mastectomy and chemotherapy.

“I had everything to live for,” she told The Wall Street Journal. “From the beginning I made the most radical choice.” After her surgery and breast reconstruction, her doctor urged her take the Oncotype DX test before deciding on chemotherapy. Her score was five.

“Once I got the result, it was a no-brainer for me,” she said. She skipped chemo. That was nearly 8 years ago. “I haven’t looked back,” she said.

Mary Lou Smith, a breast cancer survivor who helped design the trial for Eastern Cooperative Oncology Group, which is running the study said patients love the idea of taking a test to help reduce their uncertainty about treatment.

“I’ve had chemotherapy. It’s not pretty,” she said.

Results on patients with higher Oncotype DX scores will require longer follow-up before they can be released. Jennifer Litton, a breast medical oncologist at the University of Texas MD Anderson Cancer Center in Houston, who wasn’t a researcher on the study, told The Wall Street Journal she is eager to see those results because treatment questions for high-risk patients are harder to answer.

“That’s the tougher conversation with patients,” she said.

The Associated Press contributed to this report.