Thousands of women with early stage breast cancer could avoid invasive chemotherapy if found by a test to be at low risk of the cancer recurring or spreading, according to a new study.
The test -- which uses gene identifiers instead of clinical diagnosis and other factors to identify those at low risk -- is on the market but not widely used because no large-scale random trial was carried out, until now.
Close to 7,000 breast cancer patients both received a traditional clinical diagnosis and were tested under the five-year MANDACT (Micro-Array for Node-negative Disease may Avoid Chemotherapy Trial).
Some 1,550 were found to be high-risk using traditional methods but low-risk by the gene test, which looks at 70 different signatures. It was developed by the Netherlands Cancer Institute and marketed as Mammaprint by Agendia, a biotech company.
The European study, published by the New England Journal of Medicine, randomly separated those women, with a percentage treated with chemotherapy and the others agreeing not to undergo treatment.
“After five years, those that did not have chemotherapy, 95 percent were clear,” Dr. Laura Veer, a molecular biologist at the University of California, San Francisco, told Patient Daily. “There was a slight -- but not statistically important -- increase in survival with chemotherapy, not a meaningful increase. Of those who took part in the study, cancer metastasized in 94.7 percent of those tested, and just over 96 percent for those who received chemotherapy.”
This is important as breast cancer tends to be over-treated, with 80-85 percent of patients opting for chemotherapy after being advised to do so by their physician, according to Veer.
Veer was part of the team that developed the test in the Netherlands and is a principal in Agendia, the company responsible for marketing Mammaprint.
It is estimated that 38,000 women diagnosed with breast cancer every year could decide to use the test, and therefore avoid chemotherapy, after consulting with their physicians.
“The new tools will definitely be helpful, but they often will pose challenges about what the right decision is,” David Hunter, professor of cancer at Harvard’s T.H. Chan School of Public Health, told NPR radio.
The test has been on the market in Europe for nine years and in the U.S. for five. It was approved by the Federal Drug Administration in 2007, though approval is not necessary to sell it. Most insurance plans, in addition to Medicaid and Medicare, cover the test, which costs $4,200.
Veer believes the study published last Wednesday provided the remaining piece of evidence needed to move forward.
“We wanted to make sure of the test, waiting for the last piece of evidence,” she said. “It works on a similar principle that wants to understand who needs chemotherapy at early stage breast cancer. Our focus has always been who can forego chemotherapy, and make sure at the highest level of precision.”
On a personal level, Veer is extremely happy with the results, as she knows a number of the patients who took part in the study.
“For people to realize there is a chance of survival without chemotherapy -- though it is up to the patient -- I am tremendously proud,” she said.