A comparison of baseline characteristics in patients with hormone receptor (HR)-positive, HER2-negative early breast cancer revealed that a higher proportion of patients enrolled from Asia had risk factors for disease recurrence than those enrolled from non-Asian countries, reported Jiang et al at the ESMO Asia Virtual Congress 2020 (Abstract LBA1).
Researchers presented the baseline data of patients from Asian and non-Asian countries enrolled in the open-label, phase III monarchE trial, to characterize the demographics and disease characteristics of these populations and to identify patients with high-risk features who may benefit from additional adjuvant treatment.
They explained that, even though the risk of recurrence for many patients with HR-positive, HER2-negative early breast cancer is relatively low—since breast cancer is diagnosed at an early stage in approximately 90% of patients—the degree of risk may be increased by certain clinical and/or pathologic features, including the number of lymph nodes involved, tumor size, histologic grade, and the proliferation index. In addition, the clinical characteristics of patients with breast cancer are known to differ in Asian compared to Western countries.
The monarchE trial enrolled women and men with early breast cancer and four or more positive nodes, or one to three nodes plus either tumor size ≥ 5 cm, histologic grade 3, or central Ki-67 ≥ 20%. Patients with HR-positive, HER2-negative, node-positive, high-risk early breast cancer were randomly assigned via an interactive Web response system and stratified by prior treatment, menopausal status, and region (North America/Europe vs Asia vs other). Following random assignment, patients received standard-of-care endocrine therapy with or without abemaciclib at 150 mg twice daily for up to 2 years.
The study enrolled 1,155 patients from Asia from July 2017 to August 2019, including 377 from Japan, 357 from China, 245 from Korea, 124 from Taiwan, 32 from Singapore, and 20 from Hong Kong. The study also enrolled 4,482 patients from non-Asia (abemaciclib/endocrine therapy arm, n = 2,235; endocrine therapy arm, n = 2,247).
Baseline Characteristics Identified
“These characteristics suggest that patients from Asia may have a higher risk of recurrence than patients from non-Asia and would benefit from additional adjuvant treatment.”— Jiang et al
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Comparison of patients from Asia and those not from Asia revealed the former tended to be younger, more commonly premenopausal, and had a higher incidence of four or more positive lymph nodes.
Specifically, patients from Asia receiving abemaciclib plus endocrine therapy vs those on endocrine therapy had median ages of 48 (range = 23–87) vs 48 (range = 23–84); 58.6% vs 58.4% had premenopausal status; 34.7% vs 34.5% had one to three positive nodes; and 65.1% vs 65.3% had four or more positive lymph nodes, respectively.
In contrast, patients in the respective treatment groups from non-Asia had median ages of 52 (range = 25–89) vs 52 (range = 22–86); 39.6% vs 39.7% had premenopausal status; 41.2% vs 41.9% had one to three positive nodes; and 58.5% vs 57.8% had four or more positive lymph nodes.
Across all four subsets, the majority of patients were female (99.8%, 99.7%, 99.1%, and 99.4%, respectively).
The authors stated that, to their knowledge, these are the first reported baseline characteristics in patients from Asia with high-risk early breast cancer in a study investigating a cyclin-dependent kinase 4 or 6 inhibitor as adjuvant therapy.
They concluded, “These characteristics suggest that patients from Asia may have a higher risk of recurrence than patients from non-Asia and would benefit from additional adjuvant treatment.”
Disclosure: Funding was reported from Eli Lilly and Company. For full disclosures of the study authors, visit oncologypro.esmo.org.