Risk Factors of Developing Leptomeningeal Seeding After Resection of Brain Metastasis in Patients With Breast Cancer: Defining the Indication for Preoperative SRS.

Background/aim: This study aimed to identify the incidence and risk factors for leptomeningeal seeding (LMS) in patients with breast cancer following brain metastasis resection and radiotherapy (RT) and to determine potential candidates for preoperative stereotactic radiosurgery (SRS).

Patients And Methods: Between 2012 and 2022, 33 patients with breast cancer underwent surgical resection and postoperative RT for newly detected brain metastases. Twenty-one patients received whole-brain RT, while 12 patients were treated with SRS. Survival and incidence of LMS development were retrospectively analyzed. Several risk factors for the development of LMS were identified.

Results: After a median follow-up of 25.3 months, the 1- and 3-year overall survival (OS) rates were 81.2% and 58.1%, respectively. Development of LMS was the only significant factor affecting OS in multivariate analysis (Hazard ratio=3.08). Significant risk factors for LMS included age ≤45 years, triple-negative breast cancer (TNBC), and piecemeal resection. The 1-year LMS risk was 85.7% for younger patients, 46.2% for those with TNBC or piecemeal resection, and 11.1% for older patients without TNBC undergoing en-bloc resection.

Conclusion: Patients with breast cancer brain metastases who were ≤45 years old, had TNBC, or underwent piecemeal resection were at high risk of developing LMS, regardless of the postoperative RT technique used. Patients with these risk factors are essential candidates for alternative treatment approaches, such as preoperative SRS.