High-precision stereotactic irradiation for focal drug-resistant epilepsy versus standard treatment: a randomized waitlist-controlled trial (the PRECISION trial).

INTRODUCTION: The standard treatment for patients with focal drug-resistant epilepsy (DRE) who are not eligible for open brain surgery is the continuation of anti-seizure medication (ASM) and neuromodulation. This treatment does not cure epilepsy but only decreases severity. The PRECISION trial offers a non-invasive, possibly curative intervention for these patients, which consist of a single stereotactic radiotherapy (SRT) treatment. Previous studies have shown promising results of SRT in this patient population. Nevertheless, this intervention is not yet available and reimbursed in the Netherlands. We hypothesize that: SRT is a superior treatment option compared to palliative standard of care, for patients with focal DRE, not eligible for open surgery, resulting in a higher reduction of seizure frequency (with 50% of the patients reaching a 75% seizure frequency reduction at 2 years follow-up). METHODS: In this waitlist-controlled phase 3 clinical trial, participants are randomly assigned in a 1:1 ratio to either receive SRT as the intervention, while the standard treatments consist of ASM continuation and neuromodulation. After 2-year follow-up, patients randomized for the standard treatment (waitlist-control group) are offered SRT. Patients aged ≥ 18 years with focal DRE and a pretreatment defined epileptogenic zone (EZ) not eligible for open surgery will be included. The intervention is a LINAC-based single fraction (24 Gy) SRT treatment. The target volume is defined as the epileptogenic zone (EZ) on all (non) invasive examinations. The seizure frequency will be monitored on a daily basis using an electronic diary and an automatic seizure detection system during the night. Potential side effects are evaluated using advanced MRI, cognitive evaluation, Common Toxicity Criteria, and patient-reported outcome questionnaires. In addition, the cost-effectiveness of the SRT treatment will be evaluated. DISCUSSION: This is the first randomized trial comparing SRT with standard of care in patients with DRE, non-eligible for open surgery. The primary objective is to determine whether SRT significantly reduces the seizure frequency 2 years after treatment. The results of this trial can influence the current clinical practice and medical cost reimbursement in the Netherlands for patients with focal DRE who are not eligible for open surgery, providing a non-invasive curative treatment option. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT05182437. Registered on September 27, 2021.

Procedural blood pressure and contrast extravasation on dual energy computed tomography after endovascular stroke treatment.

BACKGROUND: Blood brain barrier disruption (BBBD) can be visualized by contrast extravasation (CE) after endovascular treatment (EVT) in patients with acute ischemic stroke. Elevated blood pressure is a risk factor for BBBD. However, the association between procedural blood pressure and CE post-EVT is unknown. METHODS: In this single-center retrospective study, we analyzed 501 eligible patients who received a dual energy CT (DECT) immediately post-EVT for acute ischemic stroke. Procedural blood pressure values (SBPmean, SBPmax, SBPmax-min, and MAPmean) were collected. CE was quantified by measuring the maximum parenchymal iodine concentration on DECT iodine overlay map reconstructions. As a measure for the extent of BBBD, we created CE-ASPECTS by deducting one point per hyperdense ASPECTS region on iodine overlay maps. The association between blood pressure and CE was assessed using multivariable linear regression. RESULTS: The procedural SBPmean, SBPmax, and MAPmean were 150 ± 26 mmHg, 173 ± 29 mmHg, and 101 ± 17 mmHg, respectively. The median maximum iodine concentration on post-EVT DECT was 1.2 mg/ml (IQR 0.7-2.0), and median CE-ASPECTS was 8 (IQR 5-11). The maximum iodine concentration was not associated with blood pressure. SBPmean, SBPmax, and MAPmean were significantly associated with CE-ASPECTS (per 10 mmHg, ß = -0.2, 95 % CI -0.31 to -0.09, ß = -0.15, 95 % CI -0.25 to -0.06, ß = -0.33, 95 % CI -0.49 to -0.17, respectively). CONCLUSION: In acute ischemic stroke patients undergoing EVT, particularly in patients achieving successful recanalization, SBPmean, SBPmax, and MAPmean are associated with the extent of BBBD on immediate post-EVT DECT, but not with maximum iodine concentration.

Validation of reference genes in human chordoma.

BACKGROUND: Chordoma are rare slow-growing tumors of the axial skeleton, which are thought to arise from remnants of the notochord. Little is known about the underlying mechanisms that drive this tumor. However, the assessment of gene expression levels by quantitative real-time polymerase chain reaction (qRT-PCR) is hampered due to a lack of validated reference genes. Using an unstable reference gene in qRT-PCR may lead to irreproducible results. METHODS: The expression of 12 candidate reference genes (ACTB, B2M, T, EF1a, GAPDH, HPRT, KRT8, KRT19, PGK1, RS27a, TBP, and YWHAZ) was analyzed by qRT-PCR in flash frozen chordoma samples from 18 patients. GeNorm and NormFinder algorithms were used to rank the stability of the genes. RESULTS: From most to least stably expressed, the top six genes found by geNorm were PGK1, YWHAZ, ACTB, HPRT, EF1A, and TBP. When analyzed by NormFinder, the top six genes were ACTB, YWHAZ, PGK1, B2M, TBP, and HPRT. GAPDH alone, which is often used as a reference gene in chordoma gene expression studies, is not stable enough for reliable results. CONCLUSION: In gene expression studies of human chordomas, PGK1, ACTB, and YWHAZ are more stably expressed, and therefore, are preferred reference genes over the most often used reference gene so far, GAPDH.

Notochord isolation using laser capture microdissection.

BACKGROUND: Chordoma are malignant tumors of the axial skeleton, which arise from remnants of the notochord. The Notochord (chorda dorsalis) is an essential embryonic structure involved in the development of the nervous system and axial skeleton. Therefore, the notochord seems to be the most biologically relevant control tissue to study chordoma in molecular biology research. Nevertheless, up to now mainly different tissues but not the notochord have been used as control for chordoma, due to difficulty of isolating notochordal tissue. Here, we describe a fast and precise method of isolating notochordal cells. METHODS: Examination of human fetuses, with a gestation of 9, 11 and 13 weeks, using (immuno)histochemical methods was performed. To isolate pure notochord cells for further molecular biology investigation five flash frozen fetuses between 9 and 10 weeks of gestation were dissected by microtome slicing. Thereafter pure notochord cells for further molecular biology investigation where harvested by using laser capture microdissection (LCM). RNA was extracted from these samples and used in quantitative PCR. RESULTS: This study illustrates notochord of embryonic spines in three different stages of gestation (9-11-13 weeks). Immunohistochemical staining with brachyury showed strong staining of the notochord, but also weak staining of the intervertebral disc and vertebral body. LCM of notochord slices and subsequent total RNA extraction resulted in a good yield of total RNA. qPCR analysis of two housekeeping genes confirmed the quality of the RNA. CONCLUSION: LCM is a fast and precise method to isolate notochord and the quality and yield RNA extracted from this tissue is sufficient for qPCR analysis. Therefore early embryo notochord isolated by LCM is suggested to be the gold standard for future research in chordoma development, classification and diagnosis.