Adjuvant Goserelin and Tamoxifen in Premenopausal Patients With Breast Cancer: 20-Year Trial Update

By: Victoria Kuhr, BA
Posted: Friday, October 21, 2022

A 20-year follow-up of the Stockholm trial reported that premenopausal patients with estrogen receptor–positive breast cancer saw a benefit in treatment from 2 years of adjuvant endocrine therapy. However, Annelie Johansson, MSc, PhD, of the Karolinska Institutet, Stockholm, and colleagues observed that the combination of goserelin and tamoxifen therapy showed no benefit over single treatment alone. These findings were published in the Journal of Clinical Oncology.

“The observed differential treatment benefit suggests that 2 years of the estrogen receptor–agonist and –antagonist tamoxifen more effectively prevents late recurrences in genomic low-risk patients,” said the study authors, “whereas 2 years of goserelin, inducing rapid systemic estrogen depletion, most effectively reduces the early risk in the more aggressive genomic high-risk tumors.”

A secondary analysis was conducted on data from the 1990–1997 Stockholm trial. This trial randomly assigned 924 premenopausal patients to receive 2 years of goserelin (3.6 mg subcutaneously once every 28 days), tamoxifen (40 mg orally once daily), combined goserelin and tamoxifen, and a no adjuvant–endocrine therapy control.

In 2020, gene-expression profiling of 586 patients was conducted. Median patient age was 47 years. The combination of goserelin and tamoxifen significantly improved long-term distant recurrence–free interval compared with the control. Significant goserelin/tamoxifen interaction was observed (P = .016).

Overall, 305 patients had genomic low-risk disease. This subgroup of patients significantly benefited from tamoxifen, and 158 patients with genomic high-risk disease significantly benefited from goserelin. An increased risk from the addition of tamoxifen to goserelin was seen in patients with genomic high-risk disease. The patients’ genomic risk was assessed using a 70-gene signature. This signature suggests high genomic risk is associated with more aggressive tumor characteristics, such as larger tumor size, higher grade, and HER2-positive status. Interpatient heterogeneity was also present in this signature. Additionally, approximately 40% of patients with genomic high-risk disease had lymph node–negative disease or low-proliferative tumors.

Disclosures: For full disclosures of the study authors, visit ascopubs.org.

Journal of Clinical Oncology

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