Effect of MLC tracking latency on conformal volumetric modulated arc therapy (VMAT) plans in 4D stereotactic lung treatment

AbstractBackground and purposeThe latency of a multileaf collimator (MLC) tracking system used to overcome respiratory motion causes misalignment of the treatment beam with respect to the gross tumour volume, which may result in reduced target coverage. This study investigates the magnitude of this effect.Material and methodsSimulated superior–inferior breathing motion was used to construct histograms of isocentre offset with respect to the gross tumour volume (GTV) for a variety of tracking latencies. Dose distributions for conformal volumetric modulated arc therapy (VMAT) arcs were then calculated at a range of offsets and summed according to these displacement histograms. The results were verified by delivering the plans to a Delta4 phantom on a motion platform.ResultsIn the absence of an internal target margin, a tracking latency of 150ms reduces the GTV D95% by approximately 2%. With a margin of 2mm, the same drop in dose occurs for a tracking latency of 450ms. Lung V13Gy is unaffected by a range of latencies. These results are supported by the phantom measurements.ConclusionsAssuming that internal motion can be modelled by a rigid translation of the patient, MLC tracking of conformal VMAT can be effectively accomplished in the absence of an internal target margin for substantial breathing motion (4s period and 20mm peak–peak amplitude) so long as the system latency is less than 150ms

Prophylactic radiotherapy for the prevention of procedure-tract metastases after surgical and large-bore pleural procedures in malignant pleural mesothelioma (SMART): a multicentre, open-label, phase 3, randomised controlled trial.

The use of prophylactic radiotherapy to prevent procedure-tract metastases (PTMs) in malignant pleural mesothelioma remains controversial, and clinical practice varies worldwide. We aimed to compare prophylactic radiotherapy with deferred radiotherapy (given only when a PTM developed) in a suitably powered trial.This article is freely available via Open Access. Click on the 'Additional Link' above to access the full-text via the publisher's site.Published (Open Access

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

A quality improvement intervention to enhance performance and perceived confidence of new internal medicine residents

Background: Orientation for new medical residents is challenging due to the diversity of prior experiences and cultural backgrounds and is compounded by a lack of orientation curricula that adequately addresses the needs of the medical residents to allow them to perform their duties in an efficient manner from the start. The beginning of residency training is associated with reduced quality of healthcare widely referred to as the ‘July effect’. Objective: To assess the impact of a peer-led orientation for new interns on (a) self-reported confidence level, (b) improvement in performance of first-year residents in appropriate clinical documentation and efficient discharge procedures and protocols. Design/methods: In June 2016, a hybrid of interactive teaching and simulation exercises was used to teach documentation of critical information, such as discharge medication reconciliation and discharge summary. A handout of an intern guide/manual was also provided. The previous year’s data served as comparison/control data. Comparison data were obtained for both groups from hospital’s utilisation review department. Results: Twenty-one of 23 expected new interns (91%) participated in the intervention. There was a significant decrease in non-compliance for clinical documentation in the intervention group compared to the control group. The self-reported confidence level in the intervention group increased 34%. Conclusions: Such peer-to-peer orientation has the potential to effectively improve appropriate documentation and discharge process by new residents and may help to reduce the ‘July effect’

Long-Term Results of Dose-Intensified Fractionated Stereotactic Body Radiation Therapy (SBRT) for Painful Spinal Metastases

PURPOSE To report long-term outcome of fractionated stereotactic body radiation therapy (SBRT) for painful spinal metastases. METHODS AND MATERIALS This prospective, single-arm, multicenter phase 2 clinical trial enrolled 57 patients with 63 painful, unirradiated spinal metastases between March 2012 and July 2015. Patients were treated with 48.5 Gy in 10 SBRT fractions (long life expectancy [Mizumoto score ≤4]) or 35 Gy in 5 SBRT fractions (intermediate life expectancy [Mizumoto score 5-9]). Pain response was defined as pain improvement of a minimum of 2 points on a visual analog scale, and net pain relief was defined as the sum of time with pain response (complete and partial) divided by the overall follow-up time. RESULTS All 57 patients received treatment per protocol; 32 and 25 patients were treated with 10- and 5-fraction SBRT, respectively. The median follow-up of living patients was 60 months (range, 33-74 months). Of evaluable patients, 82% had complete or partial pain response (responders) at 3 months' follow-up (primary endpoint), and pain response remained stable over 5 years. Net pain relief was 74% (95% CI, 65%-80%). Overall survival rates of 1, 3, and 5 years were 59.6% (95% CI, 47%-72%), 33.3% (95% CI, 21%-46%), and 21% (95% CI, 10%-32%), respectively. Freedom from local spinal-metastasis progression was 82% at the last imaging follow-up. Late grade-3 toxicity was limited to pain in 2 patients (nonresponders). There were no cases of myelopathy. SBRT resulted in long-term improvements of all dimensions of the 5-level EuroQol 5-Dimension Questionnaire except anxiety/depression. CONCLUSIONS Fractionated SBRT achieved durable pain response and improved quality of life at minimum late toxicity

Risk factors for vertebral compression fracture after spine stereotactic body radiation therapy: Long-term results of a prospective phase 2 study

PURPOSE: To identify frequency, clinical relevance and risk factors for vertebral compression fracture (VCF) after spine stereotactic body radiation therapy (SBRT) with long-term follow up (FU). METHODS: From 2012 to 2015, 61 lesions (56 patients) were treated within a prospective multicenter phase 2 study (NCT01594892) of SBRT for painful vertebral metastases. Post-SBRT VCF were identified. Anatomical segments, normal and tumor tissue of treated vertebrae were segmented for volumetric analyses. Predictive factors for VCF were identified by logistic regression. RESULTS: Median clinical and radiological FU for all patients was 16.2 months (range, 0-68.2) and 7.8 months (range, 0-66.9), respectively. Local metastasis control was observed in 82% of lesions at last imaging FU. Post-SBRT VCF occurred in 21 lesions (34.4%): 16.4% showed a progressive VCF, while a new VCF occurred in 18.0%. 3/56 (5.4%) patients developed painful VCF defined as pain increase by ≥2 on the visual analogue scale (VAS) and 2 (3.6%) patients required surgical stabilization. Pre-SBRT VCF, localization in the thoracic spine, Bilsky score >0, SINS score, pre-SBRT osteolytic volume and metastatic vertebral body (VB) involvement were predictive factors for VCF on univariate analysis. Relative VB involvement, osteolytic volume and pre-SBRT VCF remained in the multivariate logistic regression model that had AUC = 0.930, 83.3% sensitivity and 96.6% specificity. CONCLUSION: Spine SBRT resulted in favorable long-term pain and local metastasis control. Despite post-SBRT VCF being observed after one third of treatments, this was symptomatic in only 5% of patients. Predictive factors for developing VCF were identified which could contribute to better selection of patients for spine SBRT

Stereotactic body radiotherapy for centrally located inoperable early-stage NSCLC: EORTC 22113-08113 LungTech phase II trial results

BackgroundThe international EORTC phase II single-arm LungTech trial 22113-08113 assessed safety and efficacy of stereotactic body radiotherapy (SBRT) in patients with centrally located early-stage non-small cell lung cancer (NSCLC).Patients and MethodsPatients with inoperable non-metastatic central NSCLC (T1-T3 N0 M0, ≤7cm) were included. After prospective central imaging review and radiation therapy quality assurance (RTQA) for any eligible patient, SBRT (8x7.5 Gy, ICRU 83) was delivered. The primary endpoint was freedom from local progression probability at three years after start of SBRT.ResultsThe trial was closed earlier due to poor accrual related to repeated safety-related pauses in recruitment. Between 08/2015 and 12/2017, 39 patients from 6 European countries were included and 31 were treated per protocol and analyzed. Patients were mainly male (58%) with a median age of 75 years. Baseline comorbidities were mainly respiratory (68%) and cardiac (48%). Median tumor size was 2.6 cm (range, 1.2-5.5) and most cancers were T1 (51.6%) or T2a (38.7%) N0 M0 and of squamous cell origin (48.4%). Median follow-up was 3.6 years. The 3-year freedom from local progression and overall survival rates were 81.5% (90% CI: 62.7-91.4%) and 61.1% (90%CI: 44.1-74.4%), respectively. Cumulative incidence rates of local, regional and distant progression at 3 years were 6.7% (90% CI: 1.6-17.1%), 3.3% (90% CI: 0.4 – 12.4%) and 29.8% (90% CI: 16.8 – 44.1%), respectively. SBRT-related acute and late AEs ≥ G3 were reported in 6.5% (n=2, including one G5 pneumonitis in a patient with prior interstitial lung disease) and 19.4 % (n=6, including one lethal hemoptysis after a lung biopsy in a patient receiving anticoagulants), respectively.ConclusionThe LungTech trial suggests that SBRT with 8×7.5Gy for central lung tumors in inoperable patients is associated with acceptable local control rates. However, late severe adverse events may occur after completion of treatment. This SBRT regimen is a viable treatment option after thorough risk-benefit discussion with patients. To minimize potentially fatal toxicity, careful management of dose constraints and post-SBRT interventions is crucial