SAN DIEGO – About 70 percent of breast cancer patients are estrogen-positive.
Doctors can't predict which of them will respond to standard estrogen-blocking drugs. Forty percent of them won't respond, and their cancers grow despite treatment.
Now, a researcher in California has found a diagnostic test that may tell doctors who will respond and who won't.
Helen Eckman was diagnosed with breast cancer when she was 42 and 49.
"Then, surprisingly, at 65, I was diagnosed with breast cancer that had gone and metastasized into my bones," she said.
Eckman is estrogen-positive, but there wasn't a reliable test to see if she'd respond to standard therapy.
Researcher Svasti Haricharan, assistant professor at the Department of Tumor Microenvironment and Cancer Immunology at Sanford Burnham Prebys, is working to change that.
"We identified one particular protein that when it's lost or defective in women with breast cancer, they do not respond to standard care," Haricharan said.
That's about a third of estrogen-positive women in Haricharan's study.
She hopes to use an existing test that identifies the DNA defect in colorectal patients and a drug for metastatic breast cancer for treatment-resistant patients.
"The drug already is FDA approved, it's already in the clinic. The diagnostic test for this protein is already FDA approved and in the clinic. It's just a question of bringing them both together," Haricharan said.
Existing approval means the test and treatment can get to patients more quickly.
"My hope is that even though I've gone through this journey painfully, but well, I would hope that my daughters and my granddaughters won't have to go through it at all," Eckman said.
The drug has worked in a clinical trial already.
Haricharan estimates that the diagnostic test will be available in the next five years.