Eﬀect of Primary Breast Surgery on Prognosis in Breast Cancer Patients with Isolated Bone Metastases

San Antonio Breast Cancer Symposium (SABCS) 2025, Texas, Amerika Birleşik Devletleri, 9 - 12 Aralık 2025, ss.2053, (Özet Bildiri)

Background: Breast cancer patients presenting with isolated bone metastases represent a distinct subgroup with relatively favorable

prognosis compared to those with visceral metastases. The role of primary breast surgery in this population remains controversial, with

limited consensus on its impact on survival outcomes. Clarifying the prognostic eﬀect of surgical intervention on the primary tumor may

guide optimal treatment strategies. In this study, we evaluated the impact of primary breast surgery on survival prognosis and other

prognostic factors in patients with isolated bone metastases. Method: This retrospective study analyzed data from the Surveillance,

Epidemiology, and End Results (SEER) database, including patients with isolated bone metastatic breast cancer, between 2000 and 2021.

Relevant demographic and clinicopathological variables were extracted to assess their association with overall survival. Survival analyses

were conducted using Kaplan-Meier estimates, and independent prognostic factors were identified through multivariate Cox proportional

hazards modeling. Results: A total of 6,500 patients were identified who met the study criteria. 3398 (52.3%) of the patients were under the

age of 65. Breast cancer subtype rates were determined as follows: HR+/HER2- (77.2%), HR+/HER2+ (12.8%), HR-/HER2- (6.5%), and

HR-/HER2+ (3.5%). All patients had at least one bone metastasis, and there were no other metastases, including distant lymph node

metastasis. Surgery was performed in 1513 patients (23.4%). The number of patients who received breast radiotherapy was 124 (1.9%), and

the rate of patients who received chemotherapy was 62.8%. The 5-year survival rate was found to be statistically significantly higher in the

patient group who underwent surgery (59.5% versus 38.6%) (p<0.001). Other factors were evaluated in terms of prognosis, including age (p

< 0.001), gender (p = 0.184), race (p < 0.001), origin (p = 0.331), histopathological subtype (p < 0.001), radiotherapy (p < 0.001), and

chemotherapy (p < 0.001). Multivariate analysis confirmed that breast surgery had a statistically significant eﬀect on overall survival (p <

0.001, HR: 0.40). Conclucions: Isolated bone metastatic breast cancer is a special subtype in disease presentation. In recent years, new

drugs that improve survival compared to chemotherapy have been introduced in breast cancer, and primary breast surgery should also be

considered in selected patients with isolated bone metastatic breast cancer.