Dr Meattini on Adjuvant Radiotherapy vs Endocrine Therapy in Early Breast Cancer

"We showed a statistically significant improvement in patients receiving radiation therapy as a single modality after breast cancer surgery as compared to endocrine therapy."

Icro Meattini, ​MD, an associate professor in the Department of Clinical and Experimental Biomedical Sciences at the University of Florence; as well as a clinical oncologist in the Radiation Oncology Unit in the Oncology Department and head of the Breast Unit and Breast Cancer Multidisciplinary Team at Florence University Hospital, discusses findings from a preplanned interim analysis of the phase 3 EUROPA trial (NCT04134598) investigating the use of adjuvant endocrine therapy or radiation therapy alone in patients at least 70 years of age with luminal-like early breast cancer.

EUROPA enrolled 926 patients 70 years of age or older with invasive breast cancer who had undergone breast-conserving surgery with or without sentinel node biopsy. Patients were randomly assigned 1:1 to exclusively receive postoperative radiotherapy or adjuvant endocrine therapy. The study’s primary end points were the 5-year ipsilateral breast tumor recurrence (IBTR) rate and the health-related quality of life global health score (HRQOL GHS) outcomes at 2 years. This interim analysis was planned to be performed when at least 152 patients reached their 2-year QOL assessment. 

In EUROPA, patients who received single-modality, adjuvant radiation therapy had significantly improved QOL outcomes compared with those who received single-modality endocrine therapy, Meattini says. The mean change in European Organisation for Research and Treatment of Cancer QOL Questionnaire Core 3 GHS score from baseline to 24 months was –1.1 (standard deviation [SD], 18.8) in the radiotherapy arm (n = 104) vs –10.0 (SD, 25.8) in the endocrine therapy arm (n = 99).

Statistically significant improvements were seen with radiation therapy in most of the functional and symptom domains evaluated, he explains. Furthermore, investigators observed no differences in rates of local relapse, breast cancer–related death, or non–breast cancer–related death between the 2 arms, he notes.

Importantly, at 24 months of follow-up, neither arm had cases of IBTR or locoregional recurrence. Additionally, no distant metastases or breast cancer–related deaths were observed.

Safety-evaluable patients in the radiotherapy arm (n = 97) developed significantly fewer adverse effects (AEs) over time compared with those in the endocrine therapy arm (n =89). The rate of treatment-emergent AEs was 67.0% in the radiotherapy arm vs 85.4% in the endocrine therapy arm (difference, –18.4%; 95% CI, –30.2% to –6.2%), he concludes.