High Recurrence Score Linked with Chemotherapy Success in Breast Cancer

A high proportion of women with breast cancer who had a high 21-gene recurrence score, were estimated to be living free from distant recurrence 5 years after treatment with adjuvant chemotherapy plus endocrine therapy, according results of the TAILORx trial¹. The trial results were recently published in JAMA Oncology.

The women examined in the trial had hormone receptor (HR)-positive, ERBB2-negative, axillary node-negative breast cancer. Their score was determined by the Oncotype assay.

Joanne Mortimer, MD, director of City of Hope’s Women’s Cancer Programs, who was not involved with the study, told CancerNetworkit’s assumed that women with a high Oncotype score who need chemotherapy in addition to endocrine therapy alone isn’t beneficial aren’t going to do well. But, she added, these women often do “incredibly well.” 

Previously, the TAILORx trial reported on its primary endpoint, showing that for women with a low recurrence score (between 11 and 25) chemotherapy did not reduce the risk of recurrence, meaning that endocrine therapy alone was sufficient for these patients.

The secondary analysis of the trial included 1389 women with a recurrence score between 26 and 100, which was considered high. Among these women, 598 (42%) had a recurrence score between 26 and 30, and 791 (58%) had a recurrence score between 31 and 100. 

Most women received docetaxel (Docefrez) and cyclophosphamide (Cytoxan) as their chemotherapy regimen (42%), and the next most common regimens were an anthracycline without a taxane (24%), an anthracycline with a taxane (18%), cyclophosphamide, methotrexate (Otrexup), and 5-fluorouracil (4%), or a different regimen (6%). A total of 6% of women received no chemotherapy.

Overall, 93.0% of women with a recurrence score between 26 and 100 were estimated to live free from distant recurrence of breast cancer at 5 years and 86.8% were estimated to live free from distant recurrence at 9 years. In addition, at 5 years, 91.0% were estimated to live free from recurrence of breast cancer at a distant and/or local regional site, 87.6% were estimated to live free from invasive disease, and 95.9% were still alive. 

For women with a recurrence score between 26 and 30, the estimated 5-year distant recurrence-free rate was 94.6% and the 9-year distant recurrence-free rate was 88.5%. For women with a recurrence score between 31 and 100, the estimated 5-year distant recurrence-free rate was 91.9% and the 9-year distant recurrence-free rate was 85.5%.

To serve as a comparison, outcomes were estimated for women had they not received adjuvant chemotherapy and only endocrine therapy. The expected 5-year rate for freedom from distant recurrence was 78.8%. For women with a recurrence score between 26 and 30, the expected rate was 89.6%, and for women with a recurrence score between 31 and 100, the expected rate was 70.7%.

“When you treat people appropriately according to their5 Oncotype score, the 5-year freedom from cancer was 93%, and while I realize that’s not 100, 93% is pretty darn good,” said Mortimer. “There was a time when we didn’t give anybody with lymph node-negative breast cancer any chemotherapy. Now, we’ve identified a group of people who need it and not only do they need it, they do incredibly well when they get it.”

References:

Sparano JA. Clinical Outcomes in Early Breast Cancer With Adjuvant Chemotherapy Plus Endocrine Therapy. JAMA Oncology. https://jamanetwork.com/journals/jamaoncology/fullarticle/2752332. Published September 30, 2019. Accessed October 8, 2019.