Recurrence Score Indicates When to Use Endocrine Therapy

The study covered in this summary was  published in Research Square  as a preprint and has not yet been peer reviewed.

Key Takeaway

• Women with early-stage hormone receptor (HR)-positive breast cancer who had low to intermediate scores on the Oncotype DX Breast Recurrence Score assay did just as well on neoadjuvant endocrine therapy and chemotherapy, suggesting that this subgroup of women could forgo chemotherapy without compromising outcomes.

Why This Matters

• Neoadjuvant endocrine therapy has been underused in the United States. The Oncotype DX Breast Recurrence Score assay may help doctors decide whether patients can avoid chemotherapy in the neoadjuvant setting and instead opt for endocrine therapy, which may increase the chances of breast conservation.

Study Design

• Researchers pooled data from two independent randomized phase 2 studies of patients with early-stage, HR-positive, HER2-negative invasive breast cancer.

• The study included 109 eligible patients from two institutions, Emory University’s Winship Cancer Institute and Massey Cancer Center at Virginia Commonwealth University.

• Both studies assigned treatment on the basis of Recurrence Score: Those with values of 0-10 received neoadjuvant endocrine therapy, those with intermediate values of 11-24 or 11-25 were randomly assigned to neoadjuvant endocrine therapy or chemotherapy, and those with the higher values of 25-100 or 26-100 received neoadjuvant chemotherapy.

Key Results

• Tumor grade was similar across the two cohorts, with the majority of patients in each group having grade 2 tumors.

• Patients at Emory received longer courses of neoadjuvant endocrine therapy, whereas patients in the chemotherapy treatment groups in both studies received a median of 6 cycles of treatment.

• The authors found no significant differences in the rates of pathologic complete response or complete clinical response between the study cohorts. 

Limitations

• Researchers did not assess the difference in side effects among the treatment groups or differences in disease recurrence.

• The study lacked long-term follow-up.

• Due to the low number of participants, researchers could only provide qualitative data on the study differences. 

• Secondary analyses of data from previously designed studies can be subject to bias. 

Disclosures

• Funding for this study was not disclosed. 

This is a summary of a preprint research study, “Using Oncotype DX Breast Recurrence Score® Assay to Define the Role of Neoadjuvant Endocrine Therapy in Early-Stage Hormone Receptor-Positive Breast Cancer.” The study has not been peer reviewed. The full text can be found at researchsquare.com.

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