Patients with Early Breast Cancer and Low Oncotype DX Scores Can Skip Chemotherapy

October 2015, Vol 6, No 9

Vienna, Austria—Patients with early breast cancer and a low Oncotype DX recurrence score can safely receive treatment with hormone therapy alone and avoid chemotherapy, according to results of the TAILORx trial, which was sponsored by the National Cancer Institute.

Patients who had a recurrence score of <11 and received hormonal therapy alone had a <1% chance of distant disease recurrence at 5 years and a <2% chance of disease recurrence at any site at 5 years.

The outcomes were excellent, regardless of the patient age, tumor size, or tumor grade in patients with node-­negative, estrogen receptor–positive, HER2-negative breast cancer, who do meet the current clinical guidelines for chemotherapy consideration in addition to hormonal therapy.

This study validates the use of Oncotype DX to guide therapy in low-risk patients (recurrence score of 0-10). The results of the TAILORx study were published simultaneously online (Sparano JA, et al. N Engl J Med. 2015 Sep 27. Epub ahead of print) to coincide with the presentation of the results at the 2015 European Cancer Congress.

“This is the first prospective clinical trial evaluating this multigene test, or any breast cancer multigene test for that matter, in which patients with early breast cancer were uniformly treated based on their Oncotype DX test results. The compelling results seen in this global study provide unequivocal support for the clinical utility of Oncotype DX to risk-stratify patients with early-stage breast cancer,” said Joseph A. Sparano, MD, Montefiore Medical Center, NY.

“These findings provide additional evidence supporting expert-derived clinical practice guidelines that recommend the use of this assay in these patients with hormone receptor–positive, node-negative invasive breast cancer,” Dr Sparano added.

The TAILORx Study

The study enrolled 10,273 patients from 1182 community-based centers and major centers in the United States, Canada, Peru, Ireland, Australia, and New Zealand. All patients enrolled in the trial had hormone receptor–positive, node-­negative, HER2-negative breast cancer with tumors of 1.1 cm to 5 cm in the greatest dimension, or tumors of 0.6 cm to 1 cm in the greatest dimension and intermediate-grade or high-grade tumors. These women met the established guidelines for considering adjuvant chemotherapy, Dr Sparano emphasized.

The patients’ tumor samples were tested with the 21-gene Oncotype DX assay to calculate their recurrence score. A recurrence score of >10 indicates a greater risk for recurrence.

Of the patients enrolled in the trial, 1656 (15.9%) with a recurrence score of 0 to 10 were assigned to receive endocrine therapy alone without chemotherapy. At 5 years, the rate of invasive disease-free survival was 93.8%, the rate of freedom from distant recurrence of breast cancer was 99.3%, and the rate of freedom from the recurrence of breast cancer at a distant or locoregional site was 98.7%. The rate of overall survival was 98%.

Dr Sparano pointed out that only 16% of the patients enrolled in TAILORx are considered low-risk (recurrence score, 0-10). Another 67% of those enrolled had a midrange recurrence score of 11 to 25 and were randomized to receive chemotherapy plus endocrine therapy or to endocrine therapy alone. It is important to determine the effect of chemotherapy in this intermediate-risk group, Dr Sparano said.

Enthusiastic Support

In an accompanying editorial, Clifford A. Hudis, MD, Memorial Sloan Kettering Cancer Center, NY, hailed these results enthusiastically (Hudis CA. 2015 Sep 28. Epub ahead of print).

“These results cannot come soon enough, given the already widespread adoption of the test as a key component of guidelines and routine clinical decision making,” Dr Hudis stated.

The cutoff for low-risk patients using Oncotype DX is set by the company at 0 to 18, but the study reported at the meeting focused only on patients with a recurrence score of 0 to 10.

Dr Hudis said that it is critical to determine the role of chemotherapy in this newly defined group of patients with a recurrence score of 11 to 17, “since there will be 2 conflicting guides to their treatment that need to be reconciled: the cutoff point used in this trial and the previously available cutoff point that is associated with the commercial test.”

Dr Hudis made another important point stating that Oncotype DX is one of several genetic tests to predict the benefit of chemotherapy.

“A less expensive and broadly distributed test would be valued globally. For now, however, this assay is the most rigorously tested option and provides proof of the principle that we can develop reproducible predictive tests to select patients who should not receive chemotherapy. In that regard, it is one more step toward precision. There are more steps ahead,” he said.

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