•Delivery of single-fraction SABR to lung tumors on a 0.35T MR-linac resulted in a 3-year local control rate of 97%.•Only 1 patient (2%) developed grade ≥3 toxicity, which was chest wall ...pain.•MR-guided SABR delivered using repeated breath-holds and with automatic beam gating, achieves good tumor control and low toxicity.
Magnetic resonance imaging (MR)-guided radiotherapy permits continuous intrafraction visualization and use of automatic triggered beam delivery, with use of smaller planning target volumes (PTV). We report on long-term clinical outcomes following MR-guided single fraction (SF) lung SABR on a 0.35 T linac.
Details of patients treated with SF-SABR for lung tumors were accessed from an ethics approved institutional database. A breath-hold 3D MR simulation scan was performed using a true FISP sequence, followed by a breath-hold 3D CT scan. The gross tumor volume (GTV) was first contoured on the breath-hold CT scan, which was then compared with contours on the 3D MR scan, before the GTV was finalized. SABR plans used step-and-shoot IMRT beams to a PTV derived by adding a 5 mm margin to the breath-hold GTV, and a 3 mm gating window was used. SABR was delivered during repeated breath-holds, using automatic beam gating with continuous visualization of the GTV in a sagittal MR plane.
Between 2018-2022, 50 consecutive patients were treated, and 69% had a primary non-small cell lung cancer. Median PTV was 11.2 cc (range 3.9-53.5); 80% of GTV’s were located ≤2.5cm from the chest wall. Prescribed doses were 34Gy (in 58%), 30Gy (32%), or between 20-28Gy (10%). After a median follow-up of 18.1 months (95% CI 12.8-23.5), the 2-year survival was 82% (89% for primary NSCLC and 62% for metastases). After a median follow-up of 16.1 months (95% CI 11.2-21.1), local recurrences developed in 2 patients (4%). The 3-year local control rate was 97%, and just 1 patient developed grade ≥3 toxicity (chest wall pain).
MR-guided SF-SABR delivery to lung tumors on a 0.35 T linac, using repeated breath-holds with automatic beam gating, achieves good tumor control and low toxicity.
Increasing evidence indicates that harmful effects are associated with the use of physical restraint.
To characterize the use of physical restraint in intensive care units. Prevalence, adherence to ...protocols, and correlates of the use of physical restraint were determined. For comparisons between ICUs, adjustments were made for differences in patients' characteristics.
A prospective, cross-sectional, observational multicenter study with a representative sample (n = 25) of all Dutch intensive care units, ranging from local hospitals to academic centers. Each unit was visited twice, and all 379 patients admitted during these visits were included and were examined for use of physical restraint.
Physical restraint was used in 23% of all patients (range, 0%-56% for different units). Of all 346 nurses interviewed, 31% reported using a protocol when applying physical restraint. When corrections were made for clustering within units, the risk for use of physical restraint was increased in patients with delirium or coma, in patients who could not communicate verbally, and in patients receiving psychoactive or sedative medications. Sex, severity of illness, and nurse to patient ratio were not independently related to use of physical restraint. In 11 units (44%), use of physical restraint was more frequent than expected on the basis of patients' characteristics, although this finding was not significant.
Physical restraint is frequently used in Dutch intensive care units. The differences in frequency between units suggest that opportunities exist to limit the use of physical restraint.
•To support decision making, we developed and validated an OS nomogram.•This nomogram is applicable for centrally located NSCLC treated with SBRT.•It consists of the parameters PTV, age, WHO status, ...tumor lobe location and ultracentral location.•The model is based on 220 patients and the external validation on 92 patients.•The nomogram showed moderate discriminatory ability and favorable predictive accuracy.
Current nomograms predicting survival prognosis after stereotactic body radiation therapy (SBRT) in non-small cell lung cancer (NSCLC) are based on peripherally located tumors. However, patients with a central lung tumor tend to be older, the tumor is often larger and fraction-schedules are risk-adapted. Therefore, we developed and externally validated a nomogram to predict overall survival (OS) in patients having centrally located early-stage NSCLC treated with SBRT.
Patients who underwent SBRT for centrally located NSCLC were identified and baseline characteristics were obtained. A nomogram was built to predict 6-month, 1-, 2- and 3-year OS using Cox proportional hazards model. The model building procedure was validated using bootstrap sampling. To determine generalizability, external validation was performed on a cohort of patients with central NSCLC treated with SBRT from another center. Discriminatory ability was measured with the concordance index (C-index) and calibration plots were used to compare Kaplan–Meier-estimated and nomogram-predicted OS.
The nomogram was built on data of 220 patients and consisted of the following variables: PTV, age, WHO performance status, tumor lobe location and ultracentral location. The C-index of the nomogram (corrected for optimism) was moderate at 0.64 (95% confidence interval (CI) 0.59–0.69). Calibration plots showed favorable predictive accuracy. The external validation showed acceptable validity with a C-index of 0.62 (95% CI 0.61–0.64).
We developed and externally validated the first nomogram to estimate the OS-probability in patients with centrally located NSCLC treated with SBRT. This nomogram is based on 5 patient and tumor characteristics and gives an individualized survival prediction.
•Use of SABR for central lung tumors has been increasing.•Central lung tumors can be subdivided into ‘moderately central’ and ‘ultracentral’.•Toxicity of SABR appears acceptable in ‘moderately ...central’ tumors.•A high toxicity is seen when ultracentral tumors are treated using SABR.•Conventional radiotherapy appears more appropriate in ultracentral tumors.
The use of stereotactic ablative radiotherapy (SABR) for central lung tumors is increasing. Centrally located lung tumors can be subdivided into two categories, namely the 'moderately central' tumors where the planning target volume is located within 2 cm of the proximal bronchial tree, and the 'ultracentral' tumors where a planning target volume (PTV) overlaps the trachea or main stem bronchi. The toxicity of SABR appears acceptable when 'moderately central' tumors are treated using techniques that comply with organs at risk tolerance doses used for prospective trials and in recent publications. A high toxicity is seen when ultracentral tumors are treated using SABR, and conventional radiotherapy appears more appropriate in such tumors as the true normal organ tolerance doses remain unknown. When ultracentral tumors are treated with non-SABR hypofractionated radiotherapy, a homogenous dose distribution in the planning target volume and limitation of both normal organ maximum point doses and volumes receiving high doses seems to be needed.
To correlate esophagus toxicity and dose-volume histogram (DVH) parameters in order to assess risks, and derive a Normal Tissue Complication Probability (NTCP) model.
Patients with a central lung ...tumor from 2 centers, who underwent stereotactic or hypofractionated radiotherapy (≤12 fractions), were analyzed. Doses were recalculated to an equivalent dose of 2 Gy with an α/β ratio of 10 (EQD210). The esophagus was manually delineated and DVH-parameters (Dmax,EQD2, D1cc,EQD2, D2cc,EQD2, D5cc,EQD2) were analyzed and used for NTCP modeling based on logistic regression analysis.
Two-hundred-and-thirty-one patients with 252 tumors were eligible. No acute or late grade 3–5 esophageal toxicity was reported. Acute grade 1–2 esophagus toxicity was recorded in 38 patients (17%). All DVH-parameters were significantly higher in patients with toxicity. NTCP models showed a 50% probability of acute grade 1–2 toxicity at a Dmax of 67 Gy EQD210 and D1cc of 42 Gy EQD210. No difference in overall survival was observed between patients with and without toxicity (p = 0.428).
As no grade 3–5 esophageal toxicity was observed in our cohort, a Dmax of 56 Gy EQD210 and a D5cc of 35.5 Gy EQD210 could be delivered without high risks of severe toxicity. The NTCP models of this study might be used as practical guidelines for the treatment of central lung tumors with stereotactic radiotherapy.
Abstract Purpose The purpose of this study is to develop a reliable tool for daily mental status classification in intensive care unit (ICU) patients for research purposes. Secondly, to identify ...patients with single, 1-day episodes of delirium and to compare them with patients having more delirium days or episodes. Patients and methods A 5-step algorithm was designed, which includes Richmond Agitation Sedation Scale and Confusion Assessment Method for the ICU scores from bedside nurses, initiation of delirium treatment, chart review, and the Confusion Assessment Method for the ICU administered by researchers. This algorithm was validated against a reference standard of delirium experts. Subsequently, a cohort study was performed in patients admitted to a mixed ICU. Results In 65 paired observations, the algorithm had 0.75 sensitivity and 0.85 specificity. Applying the algorithm, interobserver agreement was high with mean Fleiss κ of 0.94 (5 raters) and 0.97 (4 raters). In the cohort study, 1112 patients were included of whom 535 (48%) became delirious. Single, 1-day episodes occurred in 43% of the delirious patients, whom were characterized by lower age compared with those with more delirium days. Conclusions The algorithm for daily mental status classification seems to be a valid tool. In a substantial proportion of patients, delirium occurs only once during ICU admission lasting only 1 day.
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