Opportunities and Alternatives of Modern Radiation Oncology and Surgery for the Management of Resectable Brain Metastases

Abstract

Postsurgical radiotherapy (RT) has been early proven to prevent local tumor recurrence, initially performed with whole brain RT (WBRT). Subsequent to disadvantageous cognitive sequalae for the patient and the broad distribution of modern linear accelerators, focal irradiation of the tumor has omitted WBRT in most cases. In many studies, the effectiveness of local RT of the resection cavity, either as single-fraction stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic RT (hFSRT), has been demonstrated to be effective and safe. However, whereas prospective high-level incidence is still lacking on which dose and fractionation scheme is the best choice for the patient, further ablative techniques have come into play. Neoadjuvant SRS (N-SRS) prior to resection combines straightforward target delineation with an accelerated post-surgical phase, allowing an earlier start of systemic treatment or rehabilitation as indicated. In addition, low-energy intraoperative RT (IORT) on the surgical bed has been introduced as another alternative to external beam RT, offering sterilization of the cavity surface with steep dose gradients towards the healthy brain. This consensus paper summarizes current local treatment strategies for resectable brain metastases regarding available data and patient-centered decision-making.

Intraoperative radiotherapy after neurosurgical resection of brain metastases as institutional standard treatment– Update of the oncological outcome form a single center cohort after 117 procedures

“…Only 16% of our patients required WBI due to multiple BMs and/ or LMD during their whole course of cancer treatment. This is in line with data from BM patients treated with SRT [7,14,18]. LMD among our patients with an estimated one-year LMD rate of 10.4% (95% CI: 4.7-22.1%) was not observed more frequently than reported in patient series treated with postoperative SRT [14,[19][20][21].…”

“…This is in line with data from BM patients treated with SRT [7,14,18]. LMD among our patients with an estimated one-year LMD rate of 10.4% (95% CI: 4.7-22.1%) was not observed more frequently than reported in patient series treated with postoperative SRT [14,[19][20][21]. Hence, there is no evidence that the IORT procedure affects the risk of tumor cell spillage to the cerebrospinal uid by neurosurgery.…”

“…These contrast enhancing zones next to the resection cavity diminished without any speci c treatment during further FU (observed brain necrosis rate 2.6% /estimated brain necrosis rate of 3.9% at 1 year). [3,[14][15][16][17] and it stayed unchanged compared to our last publication 2021 [10] after the rst 40 treated patients. Remarkably, the high rate of suspected incomplete resections on postoperative MRI of 34.6% did not transfer into worse local control (84.7% (95% CI: 66.5-93.4%) R0 vs. 82.1% (95% CI: 58.9-93.0%) R1; p = 0.606) in univariate analysis.…”

“…With an observed RN rate 2.6% and an estimated RN rate of 3.9% at one year, we report a markedly lower RN rate compared to other published data on focal BM cavity radiotherapy. In the current literature the rates of RN rage from 5 to 25% for patients treated with SRT after resection of BM [3,14,[28][29][30]. Our comparatively low RN rate could possibly be explained by the relatively small volume of surrounding brain tissue receiving 10 Gy (V10), due to the steep dose gradient of 50 kV x-rays [10].…”

Cytoreduction of Residual Tumor Burden Is Decisive for Prolonged Survival in Patients with Recurrent Brain Metastases—Retrospective Analysis of 219 Patients

“…Improved prognosis on the one hand and lack of intracranial tumor control on the other have contributed to the growing incidence of recurrent BMs. Through ongoing research, a variety of treatment modalities such as systemic therapy and radiotherapy have been established [10][11][12][13]. However, the treatment of recurrent brain metastases remains challenging due to sparse data on surgical resection.…”