Breast Cancer Patients Who Benefit From Chemo: New TAILORx Data

New data confirm the value of using a 21-gene expression test (Oncotype DX, Genomic Health) to guide use of adjuvant chemotherapy in early breast cancer.

The new results come from a secondary analysis of the huge, federally funded Trial Assigning Individualized Options for Treatment (TAILORx), which involved more than 10,000 women with early breast cancer.

The main results from this trial, reported last year, showed that the test could identify a large cohort of women (about 70%) who could skip chemotherapy.

The new data confirm that there is a cohort of women who benefit from having chemotherapy.

Women with hormone-sensitive, HER2-negative, axillary node-negative breast cancer who had a high 21-gene recurrence score of 26 to 100, and with adjuvant chemotherapy plus endocrine therapy, had an estimated cancer-free rate of 93% at 5 years.

The outcome is "better than expected" in this population of women treated with endocrine therapy alone (79% at 5 years), say the TAILORx authors. The team was led by Joseph Sparano, MD, associate director for clinical research at the Albert Einstein Cancer Center and Montefiore Health System in New York City and vice-chair of the ECOG-ACRIN Cancer Research Group.

This secondary analysis is "a nice validation that chemotherapy is justified in recurrence scores of over 26 as it improves prognosis," Charles Shapiro, MD, director, Translational Breast Cancer Research and Cancer Survivorship, The Tisch Cancer Institute at Mount Sinai in New York City, who wasn't involved in the study, told Medscape Medical News.

The secondary TAILORx analysis was published online September 30 in JAMA Oncology to coincide with presentation during a late-breaking session at the European Society for Medical Oncology (ESMO) 2019 Annual Meeting in Barcelona, Spain.

Women Who Can Skip Chemotherapy

The TAILORx trial enrolled 10,273 women with hormone-sensitive, HER2-negative, axillary node-negative breast cancer at more than 1100 sites in the United States, Australia, Canada, Ireland, New Zealand, and Peru. Patients' tumors were analyzed using the 21-gene expression test and assigned a risk score (on a scale of 0 to 100) for cancer recurrence.

The main results were presented last year during the plenary session at the American Society of Clinical Oncology (ASCO) 2018 Annual Meeting and simultaneously published in the New England Journal of Medicine.

The results showed that about 70% of patients with a midrange (intermediate) recurrence score could be spared chemotherapy. The trial found no difference in disease-free survival whether women were treated with endocrine therapy alone or the combination of endocrine therapy with chemotherapy, as reported by Medscape Medical News at the time.

Largest Data Set in Group With High Recurrence Score

Joseph Sparano, MD

The secondary analysis focused on 1389 women in TAILORx who had a recurrence score in the high-risk range (26 and above) and underwent chemotherapy in addition to endocrine therapy following surgery.

Most patients (84%) received taxane- and/or anthracycline-containing chemotherapy regimens. The most common regimens were docetaxel/cyclophosphamide (42%), anthracycline without taxane (24%), anthracycline and taxane (18%), cyclophosphamide/methotrexate/5-fluorouracil (CMF) in 4%, other regimens in 6%, and no chemotherapy in 6%.

At 5 years, the estimated rate of freedom from recurrence of breast cancer at a distant site was 93.0% (standard error [SE], 0.8%) and at a distant and/or local regional site was 91.0% (SE, 0.8%). Invasive disease-free survival was 87.6% (SE, 1.0%), and overall survival was 95.9% (SE, 0.6%).

Five-year rates of freedom from recurrence of breast cancer at a distant site ranged from 92.3% (SE, 1.6%) to 95.5% (SE, 2.5%) for all chemotherapy regimens with the exception of CMF, which was associated with a rate of 88.5% (SE, 4.8%).

In Cox models comparing any chemotherapy regimen versus none with adjustment for tumor size, age, grade, and recurrence score gave estimated hazard ratios of 0.74 (95% CI, 0.32 - 1.69) for freedom from recurrence of breast cancer at a distant site and 0.48 (95% CI, 0.29 - 0.80) for invasive disease-free survival. This suggests "inferior" outcomes for those with a high recurrence score of 26 and above who did not have chemotherapy, the researchers note.

The initial TAILORx results "gave clinicians high-quality data to inform personalized treatment recommendations for women," Sparano said in a statement.

"This new analysis provides the largest data set on outcomes in patients with early breast cancer and high recurrence score results. It confirms the importance of using the test to identify the minority of patients who will receive a significant benefit from adding adjuvant chemotherapy to endocrine therapy," said Sparano.

Shapiro agrees. "This validates that chemotherapy is important in recurrence scores of 26 and above. That we knew, but it's nice to see it in print," he told Medscape Medical News.

TAILORx was designed and conducted by the ECOG-ACRIN Cancer Research Group with primary funding from the National Cancer Institute. Additional support was provided by the Breast Cancer Research Foundation, Komen Foundation, and US Postal Service Breast Cancer Stamp. Sparano has disclosed the following: consulting or advisory role with Genentech/Roche, Novartis, AstraZeneca, Celgene, Lilly, Celldex, Pfizer, Prescient Therapeutics, Juno Therapeutics, and Merrimack; stock and other ownership interests with MetaStat; and research funding (institutional) from Prescient Therapeutics, Deciphera, Genentech/Roche, Merck, Novartis, and Merrimack. Shapiro has disclosed no relevant financial relationships.

JAMA Oncol. Published online September 30, 2019. Full text

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