Predictors of locoregional recurrence among patients with breast cancer treated with breast-conserving therapy: New data from a retrospective cohort.

e12583 Background: Breast-conserving surgery (BCS) followed by radiotherapy has become the standard treatment for early-stage breast cancer. The primary concern of breast-conserving therapy (BCT) remains the risk of in-breast local recurrence. This study aims to provide updated data on local recurrence rates following BCT in a large cohort and to identify predictors of local recurrence for improved patient selection. Methods: This is a retrospective study that includes patients with primary early-stage breast cancer who were diagnosed between January 2010 and December 2016 and treated with upfront BCS at the American University of Beirut Medical Center (AUBMC). Data regarding clinic-demographic characteristics of the patients pre-operative imaging, cancer characteristics, and oncologic outcomes were obtained from the patients’ charts. Follow-up was conducted until August 2024. Results: A total of 320 patients were included, with a median age of 52 years (range: 29-88). The median tumor size was 1.5 cm, with 71.2% classified as T1 and 22.6% as T2. The majority had unifocal disease (n = 273; 85.6%). In terms of molecular subtypes, Luminal A comprised 48.6% (n = 155), Luminal B 37% (n = 118), and Her-2 and triple-negative subtypes accounted for 3.4% (n = 11) and 9.4% (n = 30), respectively. Wire localization of tumors was performed in nearly half of the cases (n = 148; 50.9%). Two-thirds of patients received adjuvant chemotherapy (n = 208; 65.2%), and a significant majority underwent adjuvant radiotherapy (n = 298; 95.5%), with a median interval of 116 days between surgery and radiotherapy. With a median follow-up of 102 months, the local recurrence rate was 1.9%. Multivariate analysis revealed a significant correlation between the number of positive nodes and overall recurrence, as well as between margin status and overall recurrence (p-value < 0.05). Conclusions: Local recurrence following breast-conserving surgery is becoming increasingly uncommon. Identifying predictors of cancer recurrence is crucial for the appropriate selection of candidates for BCT, ensuring better outcomes for patients.