LAUSR

Simple Summary Patients with brain metastasis (BM) are at advanced stages of metastatic cancer, and surgical resection is often required in order to avoid severe neurologic deficits. After surgery, patients are usually committed to postoperative radiotherapy. In recent years, intraoperative radiotherapy (IORT) has been proposed as an alternative to conventional postsurgical radiation approaches. This possibility has several advantages, e.g., as IORT is administered only once during the surgical procedure, patients do not have to attend several radiotherapy sessions afterward. However, the application of radiation therapy directly into the open brain during surgery might be accompanied by severe perioperative complications and, therefore, might negatively impact the overall benefit. In the present study, we show that patients who underwent surgery for BM combined with IORT do not suffer from elevated levels of perioperative complications compared to patients without IORT. Therefore, IORT constitutes a safe treatment strategy for cancer patients with BM. Abstract Intraoperative radiotherapy (IORT) of the operative cavity for surgically treated brain metastasis (BM) has gained increasing prominence with respect to improved local tumor control. However, IORT immediately performed at the time of surgery might be associated with increased levels of perioperative adverse events (PAEs). In the present study, we performed safety metric profiling in patients who had undergone surgery for BM with and without IORT in order to comparatively analyze feasibility of IORT as an adjuvant radiation approach. Between November 2020 and October 2021, 35 patients were surgically treated for BM with IORT at our neuro-oncological center. Perioperative complication profiles were collected in a prospective observational cohort study by means of patient safety indicators (PSIs), hospital-acquired conditions (HACs), and specific cranial-surgery-related complications (CSCs) as high-standard quality metric tools and compared to those of an institutional cohort of 388 patients with BM resection without IORT in a balanced comparative matched-pair analysis. Overall, 4 out of 35 patients (11%) with IORT in the course BM resection suffered from PAEs, accounting for 3 PSIs (9%) and 1 HAC (3%). Balanced matched-pair analysis did not reveal significant differences in the perioperative complication profiles between the cohorts of patients with and without IORT (p = 0.44). Thirty-day mortality rates were 6% for patients with IORT versus 8% for patients without IORT (p = 0.73). The present study demonstrates that IORT constitutes a safe and clinically feasible adjuvant treatment modality in patients undergoing surgical resection of BM.