2732 - Evolution of Radiotherapy Options for Elderly Patients with Early Stage ER+ Breast Cancer: A 10 Year Review

K. A. Skalina¹, B. Malachowska², and J. L. Fox³; ¹Department of Radiation Oncology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, ²Albert Einstein College of Medicine, Bronx, NY, ³Montefiore Einstein Comprehensive Cancer Center, Bronx, NY

Purpose/Objective(s): The past decade brought numerous developments in the treatment of early-stage, estrogen receptor positive (ER+) breast cancer. The 10-year results of CALGB 9343 published in 2013 demonstrated equivalent survival and acceptable local failure (LF) rates with the omission of radiation therapy (RT) in women 70 years and older with ER+ breast cancer. The introduction of shorter radiation courses, such as single-fraction intraoperative radiation therapy (IORT) and the 5-fraction regimen from the UK FAST-FORWARD trial have also been shown to have low LF rates at 5 years. We sought to evaluate for changing trends in patients’ radiation treatment decisions over the past decade at an academic institution offering omission of radiation to eligible patients, as well as the shorter courses in more recent years.

Materials/

Methods: This study is a retrospective review of female patients at least 70 years of age with T1-2 (up to 3cm) N0 ER+/HER2- breast cancer, seen for radiation oncology consultation between January 2013 and September 15, 2023, at a main site of an urban academic medical center. All included patients underwent lumpectomy with or without sentinel node biopsy and were potentially eligible for omission of RT.

Results: A total of 316 women met inclusion criteria with an average age of 76.4 years ± 4.9. One hundred and ten (34.8%) women chose to omit radiation therapy after informed discussion. IORT became available in January 2018, and ultra-hypofractionation was offered after the trial publication, beginning in 2021. Overall, older patients were more likely to omit radiation (p<0.0001). There was a significant association between higher Charlson comorbidity index and omission of RT (p=0.0005). Fewer patients chose to omit radiation in more recent years (Table 1), and in those opting to undergo RT, there was a statistically significant negative correlation between the year of diagnosis and length of RT course (R= -0.64, p<0.0001).

Conclusion: Our analysis demonstrates that patients are increasingly electing to choose a shorter, more convenient course of RT over omission. Future studies will be needed to determine if this choice has an impact on recurrence rate or survival.

Abstract 2732 - Table 1: Patients choice regarding RT treatment

	No RT	Long-course RT	IORT	5-fx RT
2013-2017	37.33%	62.67%
2018-2020	35.42%	39.58%	25.00%
2021-2023	28.57%	15.71%	27.14%	28.57%