Now, the choice is getting easier for some patients.
According to the Irish arm's lead investigator, Prof Maccon Keane of University Hospital Galway, this trial result "is a major advance in precision medicine for women with hormone receptor positive node negative breast cancer". I also, then, lost my hair.
Arnie Purushotham, a senior clinical adviser to Cancer Research UK who was not involved in the study, welcomed the TAILORx results as an important step toward making cancer treatment less harsh for patients.
The charity Breast Cancer Now said the findings were "practice-changing".
The new study, called TAILORx, is a large, randomized trial involving thousands of patients.
A woman with an aggressive form of breast cancer which defied chemotherapy and spread to other organs, was cured with an experimental treatment that triggered her immune system, researchers said Monday.
Patients scoring 26 or higher on the scale do benefit and receive chemotherapy.
Lead author Dr Joseph Sparano, of Montefiore Medical Centre in NY, said: "Any women with early stage breast cancer 75 or younger should have the test and discuss the results of TAILORx with her doctor".
Chemo and hormone therapy didn't work but this one-time treatment with more personalized immunotherapy did work for Perkins. This will impact about 70,000 patients a year.
According to various sites, a woman suffering from an advanced stage of breast cancer that had spread throughout her body was completely cleared off the disease. Twenty-five percent of those patients won't qualify for chemotherapy because of age or medical problems.
The study, led by the Albert Einstein Cancer Center in NY, is a rare cancer breakthrough as it can save money and instantly change practice.
The findings come from a study published simultaneously in the New England Journal of Medicine. "We can de-escalate toxic treatments and do that with certainty". Key secondary end points included freedom from recurrence of breast cancer at a distant site, freedom from recurrence of breast cancer at a distant or local-regional site, and overall survival (OS).
The study is the largest ever done of breast cancer treatment. Chemotherapy did benefit women younger than 50 who had a RS between 15 to 25.
Yet the move away from chemotherapy has been hotly debated, with some doctors warning that chemo can save lives and that a "de-escalation" of treatment could be risky. "Now we know there's no need to give chemotherapy to those patients anymore", Mitchell said.
It's not the first time breast cancer research has made headlines this week.
For decades, chemotherapy has been seen as a necessary evil when it comes to treating most kinds of breast cancer. All had received a mid-range Oncotype DX score.
Genomic Health, the company that makes the gene test, helped pay after 2016.
The study was centered on a 21-gene test performed on tumors that has been available for breast cancer patients since the early 2000s. Half of that group also got chemotherapy. The researchers are "trying to find ways" to achieve more consistent outcomes, Goff said. "I sort of viewed chemo as extra insurance", she said.
"We have to develop a new drug for every patient", Rosenberg said. "We should continue to go down that path".
Sara Kiley Watson is NPR's Science Desk intern.