Posted: Friday, January 5, 2024
According to Reshma Jagsi, MD, DPhil, of Emory University School of Medicine, Atlanta, and colleagues, postmenopausal patients with genomically selected favorable stage I breast cancer who underwent breast-conserving surgery and endocrine therapy without adjuvant radiotherapy achieved a “very low” risk of relapse. The 5-year results of the multicenter IDEA trial, which were presented during the 2023 San Antonio Breast Cancer Symposium (SABCS; Abstract GS02-08), also demonstrated a consistent trend among those younger than age 60.
A total of 200 patients between the ages of 50 and 69 with endocrine receptor–positive, progesterone receptor–positive, HER2-negative pT1 N0 unifocal invasive disease (with margins of 2 mm or wider) after breast-conserving surgery and a 21-gene recurrence score of up to 18 were eligible to avoid radiotherapy if they consented to undergo at least 5 years of endocrine therapy and surveillance. Follow-up data were provided for a median of 5.2 years. The 5-year overall and breast cancer–specific survival rates were both 100%; two deaths were documented after 5 years. The rate of freedom from disease recurrence at 5 years was 99%.
Within 5 years, two events were reported: an isolated axillary recurrence at 21 months (treated with axillary dissection and breast and regional nodal irradiation) and an ipsilateral breast event at 49 months (treated with another breast-conserving surgery). Six additional patients experienced disease recurrence more than 5 years after undergoing breast-conserving surgery. The crude rate of ipsilateral breast events for the entire follow-up period was 3.3% in patients younger than age 59 and 3.6% in those aged 60 or older; the crude overall relapse rates were 5.0% and 3.6%, respectively.
“Long-term follow-up beyond the 5-year required period of endocrine therapy will be important to determine if the risk of disease recurrence increases, particularly after discontinuation of endocrine therapy,” the investigators concluded.
Disclosure: Dr. Jagsi reported no conflicts of interest. For full disclosures of the other study authors, visit atgproductions.net.
2023 San Antonio Breast Cancer Symposium