Stereotactic radiosurgery for brain metastases from non-uterine Leiomyosarcoma: A retrospective case series

Leiomyosarcoma (LMS) is a rare malignant mesenchymal cancer derived from smooth muscle cells. The estimated incidence of brain metastases (BM) from uterine LMS ranges between 0.058 and 0.128 per 100,000 women. Moreover, studies focused on non-uterine LMS BM, and their management are scant. Herein, we determined the efficacy and safety of stereotactic radiosurgery (SRS) for the treatment of patients with BM secondary to non-uterine LMS. We identified patients with BM from non-uterine LMS who underwent CyberKnife (CK) SRS treatment. Patient, lesion, treatment, and outcome data were documented. The radiological response was evaluated per RECIST guidelines. Statistical analysis included Kaplan–Meier survival estimates and descriptive statistics. This study included 16 tumors found in four patients (mean age: 57 ± 17.9 years) with a mean overall survival of 14 months (95 % CI: 5.88–22.12 months). The lesions were located predominantly in the supratentorial region (62.5 %). The median lesion volume was 1.89 cm 3 , with most lesions treated in a single fraction (87.5 %) using a median dose of 20 Gy. At 3- and 6-month follow-ups, complete or partial responses were observed in 75 % of lesions, with local progression-free survival (PFS) rates of 100 % at 3 months and 75 % at 6 and 12 months. Only one lesion showed progression, consistent with radiation necrosis. Prior studies focused on uterine LMS BM alone or lacked tumor site stratification. Our study, the largest on non-uterine LMS BM, is the first to assess CK SRS as a standalone treatment, demonstrating its efficacy in local tumor control and PFS.