Intraoperative radiotherapy in brain metastasis surgery allows faster transition to systemic therapy.

Background: In patients with brain metastases (BMs), delay of systemic therapy (CTX) after oncologic surgery due to wound healing issues and postoperative radiotherapy might influence the oncologic outcome. Intraoperative radiotherapy (IORT) is an emerging option in neurooncology, possibly shortening the time for comprehensive treatment compared to conventional external beam radiotherapy (EBRT). The aim of this study was to compare the transition time to CTX in patients undergoing IORT or EBRT.

Methods: We performed a retrospective chart review analysis of patients undergoing surgery for BMs at our institution with either IORT or adjuvant EBRT. Either therapy was applied according to an internal standard operation procedure favoring IORT if feasible. The time (days) from surgery until the beginning of CTX was compared together with overall hospitalization time.

Results: Ninety-nine patients were analyzed from which 59 underwent adjuvant EBRT and 40 IORT. Patients undergoing resection of BMs with IORT had significantly shorter intervals to CTX (EBRT vs. IORT; 65.4 ± 54.3 days vs. 32.3 ± 28.0 days (mean±SD); P < .001). Comparing the interval to CTX between the last EBRT fraction and IORT showed no significant difference EBRT vs. IORT (26.2 ± 55.8 days vs. 32.3 ± 28.0 days (mean±SD); P = .52). The time spent hospitalized until CTX was significantly lower in the IORT group (EBRT vs. IORT 20.2 ± 9.4 days vs. 9.5 ± 7.1 days (mean±SD); P < .001).

Conclusions: IORT for BM surgery allows a faster transition to systemic oncologic therapy than conventional adjuvant EBRT.