Five-Fraction Stereotactic Radiotherapy for Brain Metastases—A Retrospective Analysis

Abstract

Purpose: To determine the safety and outcome profile of five-fraction stereotactic radiotherapy (FSRT) for brain metastases (BM), either as a definitive or adjuvant treatment. Methods: We assessed clinical data of patients receiving five fractions of 7 Gy each (cumulative physical dose of 35 Gy) to BM or surgical cavities. The primary endpoints were toxicity and radiation necrosis (RN) rates. Secondary endpoints were 1-year cumulative local control rate (LCR) and estimated overall survival (OS). Results: A total of 36 eligible patients receiving FSRT to a total of 49 targets were identified and included. The median follow up was 9 (1.1–56.2) months. The median age was 64.5 (34–92) years, the median ECOG score was 1, and the median Diagnostic-Specific Graded Prognostic Assessment (DS-GPA) score was 2. Treatment was well tolerated and there were no grade 3 adverse events or higher. The overall RN rate was 14.3% and the median time to RN was 12.9 (1.8–23.8) months. RN occurrence was associated with immunotherapy, young age (≤45 years), and large PTV. The cumulative 1-year local control rate was 83.1% and the estimated median local progression free-survival was 18.8 months. The estimated median overall survival was 11 (1.1–56.2) months and significantly superior in those patients presenting with RN. Conclusions: FSRT with 5 × 7 Gy represents a feasible, safe, and efficient fast track approach of intensified FSRT with acceptable LC and comparable RN rates for both the adjuvant and definitive RT settings.

Outcome assessment of intraoperative radiotherapy for brain metastases: results of a prospective observational study with comparative matched-pair analysis

“…This may be an additional clinical advantage of IORT over other RT techniques that requires further scientific attention. Our observed 1-year LCR of 97.1% compares well with the 94% observed by Cifarelli et al [ 19 ] and outperforms most studies on both adjuvant and definitive SRS or FSRT with rates roughly between 80 to 90% [ 14 , 17 , 18 , 49 , 54 – 56 ]. Definitive SRS of BM is the primary alternative option to resection when systemic treatment delays are to be avoided.…”

“…Moreover, arterial occlusion [ 48 ], seed detachment and necessity of subsequent re-surgery could arise. For stereotactic RT, reports on LCR and toxicity differ significantly depending on entities, BM volume and number, but also the fractionation scheme [ 14 , 15 , 17 , 18 , 49 ]. Besides classical outcome parameters, patient-centered factors such as reduction of hospitalization times, timely treatment access and quality of life have become increasingly important both from patient-centered and socioeconomic view points.…”

“…Adjuvant radiation therapy (RT) of both potential tumor remnants and the resection cavity improves local control rates (LCR) [ 12 – 14 ]. Considering the tumor localization, histology and volumes, common RT regimens apply stereotactic external-beam RT (EBRT) of one (stereotactic radiosurgery, SRS) to seven fractions (fractionated stereotactic radiotherapy, FSRT) either before resection or afterwards, following adequate wound healing and recovery from surgery [ 14 – 18 ]. As an alternative, low-energy intraoperative RT (IORT) has increasingly gained attention in the past years.…”

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

“…IORT did not increase the perioperative complications rate of brain surgery. Although our series contains cases with huge metastases up to 7cm diameter, 12% of the treated patients tted to RPA class 3 and 13% of the metastases were located in the posterior fossa, the 30-days-mortality and complication rate were within the range described in recent publications of patient cohorts after neurosurgical BM resection with or without IORT [3,9,[22][23][24][25][26]. The complete IORT procedure prolonged OR time for 25 minutes in mean including less than 16 minutes radiation time.…”

Intraoperative or postoperative stereotactic radiotherapy for brain metastases: time to systemic treatment onset and other patient-relevant outcomes

“…For large or symptomatic lesions, the standard of care includes maximal surgical resection followed by one to several fractions of adjuvant stereotactic radiotherapy (SRT), in order to improve local control. The latter yields superior outcomes over whole-brain radiotherapy in terms of neurocognition and quality of life [ 5 – 7 ]. To allow for postoperative patient stabilisation and sufficient surgical wound healing, adjuvant radiation treatment is only initiated after a postoperative interval of several weeks, which increases the overall BM treatment time and delays the onset of systemic treatments [ 8 ].…”