TAILORx Findings Augur Less-Toxic Treatment for Patients With Breast Cancer

Ariela Katz
Published: Monday, Aug 20, 2018
Joyce A. O’Shaughnessy, MD
Joyce A. O’Shaughnessy, MD
Results from the phase III TAILORx study will enable physicians to reduce the toxicity of treatment for many patients with early stage breast cancer, according to Joyce A. O’Shaughnessy, MD.

The findings will benefit those with disease that is hormone receptor (HR)–positive, HER2-negative, and axillary lymph node–negative, but changes will be fundamental, said O’Shaughnessy. “There will be less use of chemotherapy overall, but some continued use of it in the higher-risk, premenopausal patient population,” she told OncologyLive®. O’Shaughnessy is chair of breast cancer research and the Celebrating Women Chair in Breast Cancer at Texas Oncology-Baylor Charles A. Sammons Cancer Center in Dallas. She discussed the findings from the TAILORx and MINDACT trials and how the results will help clinicians select patients for more appropriate therapies.

TAILORx employed the Oncotype DX Breast Recurrence Score to investigate the relative value of hormone therapy plus chemotherapy versus hormone therapy alone in women with intermediate-risk breast cancer. The 21-gene Oncotype DX assay predicts the 10-year risk of distant recurrence in patients with early-stage, invasive breast cancer. The higher the score, the higher the risk of recurrence.1 Patients with a high recurrence score benefit from chemotherapy, whereas patients with a low score respond better to endocrine therapy and would likely receive little or no benefit from chemotherapy.

The results of the TAILORx trial (NCT00310180), presented at the 2018 American Society of Clinical Oncology Annual Meeting in June, demonstrated that adjuvant endocrine therapy alone is noninferior to adjuvant chemoendocrine therapy in patients with early-stage HR-positive, HER2-negative, node-negative breast cancer (Table). The noninferiority of endocrine therapy alone compared with endocrine therapy plus chemotherapy met the trial’s primary endpoint of invasive disease-free survival (IDFS) (hazard ratio, 1.08; 95% CI, 0.94-1.24; P = .26).2

HR-positive, HER2-negative, node-negative breast cancer is one of the most common types of breast cancer, accounting for up to 50% of breast cancers, according to lead study author Joseph A. Sparano, MD, associate director for clinical research at the Albert Einstein Cancer Center in the Bronx, New York. Up to 30% of patients with these tumors typically have a recurrence by 10 years. Although adjuvant chemotherapy is recommended for these patients, the benefit is typically small, approximately 3% to 5%.2

Trial Randomization

Of 6711 evaluable women with an intermediate recurrence score of 11 to 25, investigators randomized 3399 to receive endocrine therapy alone and 3312 to receive endocrine therapy plus chemotherapy. Randomization was based on these stratification factors: menopausal status, planned chemotherapy, planned radiation, and recurrence score groups.

After 5 years of treatment, the IDFS rate was 92.8% for those who had hormone therapy alone and 93.1% for those who also had chemotherapy. At 9 years, patients with intermediate recurrence scores receiving endocrine therapy alone and chemotherapy plus endocrine therapy showed similar IDFS rates (83.3% vs 84.3%). Also, distant recurrence-free interval (94.5% vs 95.0% with chemoendocrine therapy), recurrence-free interval (92.2% vs 92.9%, respectively), and overall survival (93.9% vs 93.8%) rates were similar between the 2 intermediate score arms at 9 years.

Among women with low-end recurrence scores (0 to 10), investigators noted a 3% distant recurrence rate with endocrine therapy alone at the 9-year mark, which confirmed findings from earlier studies; patients with high recurrence scores (26 to 100) had a distant recurrence rate of 13%, despite having received chemotherapy and hormone therapy. Investigators concluded that this indicates the need for therapies that are more effective for women at high risk of recurrence.

An exploratory analysis of patients in the 2 intermediate-range recurrence score arms considered factors that may determine which patients would benefit from added chemotherapy. Although there was no significant linkage between menopause, tumor size, or grade with recurrence score, there was a relationship between age and recurrence score.

In women 50 years or younger with a recurrence score of 16 to 20, there were 2% fewer distant recurrences; in those with a recurrence score of 21 to 25, 7% fewer. “The younger women who had a recurrence score of 16 to 25 had some chemotherapy benefit,” Sparano explained. “This was information that could drive some younger women who have a recurrence score in this range to accept chemotherapy.”

The TAILORx trial findings reconfirmed that patients of any age with low recurrence scores (0-10) would be recommended for endocrine therapy alone (16% of all patients), and all patients with high recurrence scores (26 to 100) (17%) would be recommended for chemotherapy.

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