Focal cavity radiotherapy after neurosurgical resection of brain metastases: sparing neurotoxicity without compromising locoregional control

Resection with intraoperative radiotherapy vs. adjuvant radiotherapy in the treatment of eloquent brain metastases: an analysis of feasibility and safety

INTRODUCTION

The treatment of motor eloquent brain metastases (BM) harbors an elevated risk of neurological deficits due to possible damage to motor-cortex and tracts. Preserving a good functional and neurological status is crucial to enable comprehensive oncologic treatment. Growing evidence promotes intraoperative radiotherapy (IORT) with low voltage x-rays as alternative to adjuvant external beam radiotherapy (EBRT). Aim of this study is to investigate the safety and feasibility of surgery with IORT in motor eloquent regions compared to adjuvant radiotherapy (RT).

METHODS

We performed a retrospective chart review analysis of patients undergoing surgery for motor eloquent BMs at our institution with either IORT or adjuvant RT. All patients were resected under intraoperative neuromonitoring (IONM). We compared patient characteristics, the rate of neurological deficits along with IONM parameters, functional status (KPS) and adverse events (AE) in both groups.

RESULTS

33 patients were analyzed from which 25 underwent IORT and 8 adjuvant EBRT in motor eloquent BMs. New motor deficits occurred in 7/33 patients without significant difference between both groups after 30 days (IORT 4/25 vs. adj. RT 3/8; Chi [2]-test: p = 0.19). The KPS after surgery did not differ significantly between both groups (IORT: 90% [72.5-90] vs. adj. RT: 80% [70-90]; Mann-Whitney-U-test: p = 0.31). No patient experienced local tumor recurrence or radio necrosis. 9/33 patients experienced postoperative AEs until the 30 day follow up without significantly different rates between both groups (IORT 5/25 vs. adj. RT 4/8; Chi [2]-test: p = 0.09).

CONCLUSION

50 kV photon IORT is a safe treatment option for motor eloquent BMs and does not seem to provoke in symptomatic brain irritation.

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

PURPOSE

Stereotactic radiotherapy (SRT) is the predominant method for the irradiation of resection cavities after resection of brain metastases (BM). Intraoperative radiotherapy (IORT) with 50 kV x-rays is an alternative way to irradiate the resection cavity focally. We have already reported the outcome of our first 40 IORT patients treated until 2020. Since then, IORT has become the predominant cavity treatment in our center due to patients´ choice.

METHODS

We retrospectively analyzed the outcomes of all patients who underwent resection of BM and IORT between 2013 and August 2023 at Augsburg University Medical Center (UKA).

RESULTS

We identified 105 patients with 117 resected BM treated with 50 kV x-ray IORT. Median diameter of the resected metastases was 3.1 cm (range 1.3 - 7.0 cm). Median applied dose was 20 Gy. All patients received standardized follow-up (FU) including three-monthly MRI of the brain. Mean FU was 14 months, with a median MRI FU for patients alive of nine months. Median overall survival (OS) of all treated patients was 18.2 months (estimated 1-year OS 57.7%). The observed local control (LC) rate of the resection cavity was 90.5% (estimated 1-year LC 84.2%). Distant brain control (DC) was 61.9% (estimated 1-year DC 47.9%). Only 16.2% of all patients needed WBI in the further course of disease. The observed radio necrosis rate was 2.6%.

CONCLUSION

After 117 procedures IORT still appears to be a safe and appealing way to perform cavity RT after neurosurgical resection of BM with low toxicity and excellent LC.

Intraoperative radiotherapy combined with spinal stabilization surgery-a novel treatment strategy for spinal metastases based on a first single-center experiences

INTRODUCTION

Current treatment of spinal metastases (SM) aims on preserving spinal stability, neurological status, and functional status as well as achieving local control. It consists of spinal surgery followed by radiotherapy and/or systemic treatment. Adjuvant therapy usually starts with a delay of a few weeks to prevent wound healing issues. Intraoperative radiotherapy (IORT) has previously been successfully applied during brain tumor, breast and colorectal carcinoma surgery but not in SM, including unstable one, to date. In our case series, we describe the feasibility, morbidity and mortality of a novel treatment protocol for SM combining stabilization surgery with IORT.

METHODS

Single center case series on patients with SM. Single session stabilization by navigated open or percutaneous procedure using a carbon screw-rod system followed by concurrent 50 kV photon-IORT (ZEISS Intrabeam). The IORT probe is placed via a guide canula using navigation, positioning is controlled by IOCT or 3D-fluroscopy enabling RT isodose planning in the OR.

RESULTS

15 (8 female) patients (71 ± 10y) received this treatment between 07/22 and 09/23. Median Spinal Neoplastic Instability Score was 8 [7-10] IQR. Most metastasis were located in the thoracic (n = 11, 73.3%) and the rest in the lumbar (n = 4, 26.7%) spine. 9 (60%) patients received open, 5 (33%) percutaneous stabilization and 1 (7%) decompression only. Mean length of surgery was 157 ± 45 min. Eleven patients had 8 and 3 had 4 screws placed. In 2 patients radiotherapy was not completed due to bending of the guide canula with consecutive abortion of IORT. All other patients received 8 Gy isodoses at mdn. 1.5 cm [1.1-1.9, IQR] depth during 2-6 min. The patients had Epidural Spinal Cord Compression score 1a-3. Seven patients (46.7%) experienced adverse events including 2 surgical site infection (one 65 days after surgery).

CONCLUSION

50 kV photon IORT for SM and consecutive unstable spine needing surgical intervention is safe and feasible and can be a promising technique in selected cases.

Palliative appropriateness criteria: external validation of a new method to evaluate the suitability of palliative radiotherapy fractionation

BACKGROUND

Recently, the palliative appropriateness criteria (PAC) score, a novel metric to aid clinical decision-making between different palliative radiotherapy fractionation regimens, has been developed. It includes baseline parameters including but not limited to performance status. The researchers behind the PAC score analyzed the percent of remaining life (PRL) on treatment. The latter was accomplished by calculating the time between start and finish of palliative radiotherapy (minimum 1 day in case of a single-fraction regimen) and dividing it by overall survival in days from start of radiotherapy. The purpose of the present study was to validate this novel metric.

PATIENTS AND METHODS

The retrospective validation study included 219 patients (287 courses of palliative radiotherapy). The methods were identical to those employed in the score development study. The score was calculated by assigning 1 point each to several factors identified in the original study and using the online calculator provided by the PAC developers.

RESULTS

Median survival was 6 months and death within 30 days from start of radiotherapy was recorded in 13% of courses. PRL on treatment ranged from 1 to 23%, median 8%. Significant associations were confirmed between online-calculated PAC score, observed survival, and risk of death within 30 days from the start of radiotherapy. Patients with score 0 had distinctly better survival than all other groups. The score-predicted median risk of death within 30 days from start of radiotherapy was 22% in our cohort. A statistically significant correlation was found between predicted and observed risk (p < 0.001). The original and present study were not perfectly concordant regarding number and type of baseline parameters that should be included when calculating the PAC score.

CONCLUSION

This study supports the dual strategy of PRL and risk of early death calculation, with results stratified for fractionation regimen, in line with the original PAC score study. When considering multifraction regimens, the PAC score identifies patients who may benefit from shorter courses. Additional work is needed to answer open questions surrounding the underlying components of the score, because the original and validation study were only partially aligned.

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

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.