The Multi-institutional study of ‘Sandwich treatment’ for motor area brain metastases (BM) with diameter over 3cm

‘Sandwich treatment’ for motor area brain metastases over 3cm

Abstract

Background: The objective of the present study was to explore the effectiveness and safety of ‘Sandwich treatment’ strategy for brain metastases (BM) with diameter over 3cm located in motor area.

Patients and Methods: Patients that received ‘Sandwich treatment’ from four gamma knife center were retrospectively studied from January 2016 to March 2023. The strategy was a one week treatment course which includes 2 stage SRS and using Bevacizumab once during SRS gap. The volume changes of tumor and peri-tumor edema were analyzed before and after ‘Sandwich treatment’. Manual muscle testing (MMT) score and Barthel Index (BI) score were used to evaluate the changes of patients’ movement and physical strength rehabilitation. The patients’ overall survival (OS) and tumor local control (TLC) rate was calculated for the treatment effectiveness evaluation. Cox regression model was used to analyze the risk factors that related to TLC.

Results: 61 patients with 72 lesions located in the motor area received the ‘Sandwich treatment’. The median SRS dose was 13 Gy and 12.5 Gy at first-stage and second-stage, respectively. The mean tumor volume at the time of ‘Sandwich treatment’ and 3 months later was 20.1 cm³ (range: 17.2-29.7 cm³) and 12.3 (range: 8.9-21.0 cm³), respectively (P<0.01). The mean peri-tumor edema volume at the first SSRS and second SSRS was 12.6 cm³ (range: 4.9-19.6 cm³) and 5.2 cm³ (range: 1.2-13.2 cm³), respectively (P<0.01). Patients’ median MMT score improved from 6 at the beginning to 8 at the end of ‘Sandwich treatment’ (P<0.01). Patients’ median BI score was also greatly improved 45 at the time of ‘Sandwich treatment’ to 95 after 3 months (P<0.01). Patients’ median OS was 14.0 months, and the OS rate at 3, 6, 12 months was 92.0%, 86.0% and 66.0%, respectively. The TLC rate at 3, 6, 12 months was 98.4%, 93.4%, and 85.3%, respectively. Patients with lung cancer had lower risk of tumor relapse. In the study cohort, the cumulative incidence of patient’s hemorrhage and radiation necrosis was 4.92% (3/61) and 13.11% (8/61) after ‘Sandwich treatment’.

Conclusion: ‘Sandwich treatment’ strategy is safe and effective for BM with diameter over 3cm located in motor area. The strategy could rapidly improve the patients’ movement and enhance their physical strength rehabilitation. ‘Sandwich treatment’ strategy can be considered as an alternative choice for motor area BM with diameter over 3cm.