Investigation of the risk factors in the development of radionecrosis in patients with brain metastases undergoing stereotactic radiotherapy.

OBJECTIVE: To investigate the incidence, timing, and the factors predictors radionecrosis (RN) development in brain metastases (BMs) undergoing stereotactic radiotherapy (SRT). METHODS: The study evaluated 245 BMs who exclusively received SRT between 2010 and 2020. RN was detected pathologically or radiologically. RESULTS: The median of follow-up was 22.6 months. RN was detected in 18.4% of the metastatic lesions, and 3.3% symptomatic, 15.1% asymptomatic. The median time of RN was 22.8 months (2.5-39.5), and the rates at 6, 12, and 24 months were 16.8%, 41.4%, and 66%, respectively. Univariate analysis revealed that Graded Prognostic Assessment (P = .005), Score Index of Radiosurgery (P = .015), Recursive Partitioning Analysis (P = .011), the presence of primary cancer (P = .004), and localization (P = .048) significantly increased the incidence of RN. No significant relationship between RN and brain-gross tumour volume doses, planning target volume, fractionation, dose (P > .05). Multivariate analysis identified SIR > 6 (OR: 1.30, P = .021), primary of breast tumour (OR: 2.33, P = .031) and supratentorial localization (OR: 3.64, P = .025) as risk factors. CONCLUSIONS: SRT is used effectively in BMs. The incidence of RN following SRT is undeniably frequent. It was observed that the incidence rate increased as the follow-up period increased. We showed that brain-GTV doses are not predictive of RN development, unlike other publications. In study, a high SIR score and supratentorial localization were identified as factors that increased the risk of RN. ADVANCES IN KNOWLEDGE: RN is still a common complication after SRT. Symptomatic RN is a significant cause of morbidity. The causes of RN are still not clearly identified. In many publications, brain dose and volumes have been found to be effective in RN. But, with this study, we found that brain dose volumes and fractionation did not increase the incidence of RN when brain doses were taken into account. The most important factor in the development of RN was found to be related to long survival after SRT.

Predictors of local control after robotic stereotactic radiotherapy for brain metastases: 10-years-experience after Cyberknife installation.

BACKGROUND: To evaluate the factors influencing brain metastases (BM) local control (LC) after stereotactic radiotherapy (SRT). METHODS: Between 2010 and 2020, a cohort of 145 patients (246 BM) treated consecutively with robotic radiosurgery was analysed. RESULTS: Median age was 61 years (range, 29-90 years). Median radiological follow-up of the lesions was 21.7 months (range, 3-115 months). The mean overall survival and LC were 33.0 and 82.7 months, respectively. On univariate analysis, sex, primary cancer site, histological type, use of systemic steroids, maximum diameter, volume, early MRI response, isodose line, number of fractions, BED10 value, and BED10 value proportional to volume and maximum diameter were significant factors for LC. On multivariate analysis, female sex (hazard ratio [HR]: 2.10 P: 0.035), adenocarcinoma histology (HR: 6.54 P: 0.001), no steroid use (HR: 3.60 P: 0.001), maximum diameter (≤1 cm) (HR: 2.64 P: 0.018), complete response of lesion at first follow-up MRI compared to stable or progressive disease (HR: 4.20, P = 0.024; HR: 19.15, P < 0.001), isodose line (≥90%) (HR: 2.00 P: 0.036), and tumour volume (PTV ≤2 cc) (HR: 5.19 P: 0.001) were independent factors improving LC. CONCLUSIONS: SRT is an effective treatment for patients with a limited number of BM with a high LC rate. There are many factors related to the patient, tumour, and radiotherapy plan that have an impact on LC after SRT in brain metastases. These results warrant further investigation in a prospective setting.

Environmental quality and health expenditures efficiency in Türkiye: the role of natural resources.

The environmental pollution caused by climate change and global warming pose significant risks to health. This raises the question how environmental disturbances can affect health expenditures. Based on this, this study examines the asymmetric effect of environmental quality on health expenditures in Türkiye using the non-linear ARDL (NARDL) model for the 1975-2019 period. In addition to environmental quality, natural resources, economic growth, and trade openness variables are also included in the health expenditure model. The findings support the existence of an asymmetric cointegration relationship between the series. The findings also indicate that positive environmental pollution shocks affect health expenditures positively in the long run, while negative environmental pollution shocks do not have a statistically significant effect on health expenditures. Positive and negative natural resource shocks affect health expenditures negatively in the long run. Despite the effect of positive economic growth shocks on health expenditures is positive but statistically insignificant, the effect of negative economic growth shocks is positive and significant. Besides, positive trade openness shocks have a negative effect on health expenditures and negative trade openness shocks have a positive effect. The findings prove that the steps to be taken to protect the environment in the current period will increase the effectiveness of health expenditures in the future. This situation has a guiding feature for policy-makers in terms of policy decisions.