A study presented at the 2024 San Antonio Breast Cancer Symposium (SABCS) found that older patients with luminal-like early breast cancer experienced inferior quality-of-life outcomes when treated exclusively with adjuvant endocrine therapy.

In the phase 3 EUROPA clinical trial, researchers randomly assigned women aged 70 years or older to exclusive endocrine therapy or radiation therapy following breast-conserving surgery for luminal-like early breast cancer. The study’s co-primary endpoints included 2-year health-related quality of life and 5-year ipsilateral breast tumor recurrence based on treatment assignment.

At SABCS, researchers presented a preplanned interim analysis for 2-year health-related quality of life. The analysis included data from 103 patients assigned to endocrine therapy and 104 patients assigned to radiation therapy.

The two groups had similar mean global health status scores at baseline (endocrine therapy vs radiation therapy, 75.5 ± 19.3 vs 71.9 ± 19.1). However, the mean change from baseline over the course of 24 months was higher among patients assigned to endocrine therapy (-10 ± 25.8 vs -1.1 ± 18.8).

Factors significantly associated with changes in score included treatment type (P = .045) and baseline global health score value (P < .0001). The adjusted mean changes associated with endocrine therapy were greater at 3 months (-6.45 vs -3.77), 6 months (-5.38 vs -0.59), 12 months (-6.6 vs -4.33), and 24 months (-9.79 vs -3.4).

At the time of this interim analysis, no ipsilateral breast cancer recurrence, locoregional recurrence, or distant metastatic events had been reported in either group.

Two patients assigned to radiation therapy and one patient assigned to endocrine therapy experienced contralateral breast cancer. Four deaths occurred in the radiation therapy arm and two patients died in the endocrine therapy arm, with no deaths related to breast cancer.

“The adjusted mean differences between radiation therapy and endocrine therapy arms at 24 months showed a significant difference of 6.39 favoring the radiation therapy arm (95% CI, 0.14-12.7; P = .0453). Endocrine therapy resulted in a more significant decline at 24 months in most of the functional and symptom scales of the QLQ-C30 questionnaire compared to radiation therapy.”

-Icro Meattini, MD, clinical radiation oncologist and head of the breast unit at Florence University Hospital, Florence, Italy, and the study’s presenting author.

Ahead of final study results, these initial findings can be used to inform decision-making choices for adjuvant therapy among patients and healthcare providers.

Reference:
https://sabcs.org/Portals/0/Documents/Formatted_Abstracts%2011-27%20Without%20Embargoed.pdf?ver=qjVzk5LPNjOteEIvNEYJFw%3d%3d

Disclosures: The EUROPA clinical trial is supported by Azienda Ospedaliero-Universitaria Careggi.

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