麻豆传媒

CHICAGO -- About 70% of women with the most common form of early breast cancer don't need chemotherapy after surgery, a researcher said.

The finding from a randomized clinical trial suggests a change in clinical practice for majority of women with disease that is hormone receptor-positive, HER2-negative, and axillary node-negative, according to Joseph Sparano, MD, of Albert Einstein Cancer Center and Montefiore Health System in New York City.

After surgery, most of those women are usually treated with hormone therapy and chemotherapy, Sparano told reporters here at the American Society of Clinical Oncology (ASCO) annual meeting. The results were also published in the New England Journal of Medicine.

But if they have a low or mid-range score on a genetic test for the risk of recurrence -- as did about 70% of women in the study -- chemotherapy appears to have no detectable effect on the danger of the cancer returning, Sparano said.

In clinical practice, he said, "application of this test would be expected to spare chemotherapy in about 70% of women and select chemotherapy in about 30%."

The presentation and publication of the data marks an "extraordinary day" for doctors and patients, commented ASCO expert Harold Burstein, MD, PhD, of Dana-Farber Cancer Institute in Boston.

"It allows us to individualize treatment based on extraordinary science that now has tremendous prospective validation," he said. "The most challenging decisions we make with these patients is whether or not to recommend chemotherapy with all its side effects and its potential benefits."

Now, the "vast majority of women who have this test performed on their tumor can be told they don't need chemotherapy, and that can be said with tremendous confidence and reassurance," Burstein stated.

He noted that the gene test (Oncotype DX Breast Recurrence Score) has been in use for more than a decade, based on data that suggested it was prognostic at the high and low ends. But that data was based on older chemotherapy and hormone therapies, and it was not clear how well it applied to modern treatments.

The study validates the gene test in the modern era and also clears up a "gray zone" -- how to treat women with scores that were not clearly prognostic, Burstein said.

(Trial Assigning IndividuaLized Options for Treatment) enrolled 10,273 women for what Sparano called the "largest adjuvant breast cancer trial ever performed."

It was aimed at "threading the needle," he said: Defining which women were being over- or undertreated.

On the gene test, whose possible scores range from 0 to 100, 1,629 women had tumors with a low score of ≤10 were given endocrine therapy alone, he reported. Another 1,389 had scores of ≥26 and were treated with chemotherapy in addition to endocrine therapy. Standard regimens were used, he said.

The investigators randomized the remaining 6,711 women, with scores from 11 through 25, to get endocrine therapy alone or combined treatment. The primary endpoint of the study was invasive disease-free survival -- defined as invasive disease recurrence, second primary cancer, or death -- measured on a non-inferiority basis.

The 9-year rates were almost identical -- 83.3% for those on endocrine therapy alone and 84.3% for those on combined treatment. The rates yielded a non-significant hazard ratio of 1.08, and the study met the non-inferiority criterion.

Other endpoints, such as distant recurrences and overall survival, were also similar, Sparano said.

However, an exploratory analysis suggested, however, that some women with midrange scores might still benefit from the addition of chemotherapy, Sparano said. Specifically, those ages ≤50 with a recurrence score from 16 through 25 appeared to have fewer distant recurrences if they had combined treatment.

But overall, three groups of women appear to be able to dispense with chemotherapy:

• Those of any age with a recurrence score of ≤10
• Those age >50 with a score from 11 through 25
• Those ≤50 with a score from 11 through 15

The TAILORx results by comes just a few months after a study showing that another test -- the PAM50 gene signature -- could be used to help decide which patients with early breast cancer should get adjuvant chemotherapy.