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Liu, David M.

0000-0002-5891-3609

A5100739512 | I141945490

Mayo Clinic

University of British Columbia

Citations 4

American Radium Society Appropriate Use Criteria for the use of liver‐directed therapies for nonsurgical management of liver metastases: Systematic review and guidelines

Cancer | July 6, 2023 | Volume: 129 | Issue: 20 | Pages: 3193-3212

10.1002/cncr.34931 | PMID 37409678

AbstractThe liver is a common site of cancer metastases. Systemic therapy is widely accepted as the standard treatment for liver metastases (LM), although select patients with liver oligometastases may be candidates for potentially curative liver resection. Recent data support the role of nonsurgical local therapies such as ablation, external beam radiotherapy, embolization, and hepatic artery infusion therapy for management of LM. Additionally, for patients with advanced, symptomatic LM, local therapies may provide palliative benefit. The American Radium Society gastrointestinal expert panel, including members representing radiation oncology, interventional radiology, surgical oncology, and medical oncology, performed a systemic review and developed Appropriate Use Criteria for the use of nonsurgical local therapies for LM. Preferred Reporting Items for Systematic reviews and Meta‐Analyses methodology was used. These studies were used to inform the expert panel, which then rated the appropriateness of various treatments in seven representative clinical scenarios through a well‐established consensus methodology (modified Delphi). A summary of recommendations is outlined to guide practitioners on the use of nonsurgical local therapies for patients with LM.
Deep‐learning based fast and accurate 3D CT deformable image registration in lung cancer

Medical Physics | June 8, 2023 | Volume: 50 | Issue: 11 | Pages: 6864-6880

10.1002/mp.16548 | PMID 37289193

AbstractBackgroundDeformable Image Registration (DIR) is an essential technique required in many applications of radiation oncology. However, conventional DIR approaches typically take several minutes to register one pair of 3D CT images and the resulting deformable vector fields (DVFs) are only specific to the pair of images used, making it less appealing for clinical application.PurposeA deep‐learning‐based DIR method using CT images is proposed for lung cancer patients to address the common drawbacks of the conventional DIR approaches and in turn can accelerate the speed of related applications, such as contour propagation, dose deformation, adaptive radiotherapy (ART), etc.MethodsA deep neural network based on VoxelMorph was developed to generate DVFs using CT images collected from 114 lung cancer patients. Two models were trained with the weighted mean absolute error (wMAE) loss and structural similarity index matrix (SSIM) loss (optional) (i.e., the MAE model and the M+S model). In total, 192 pairs of initial CT (iCT) and verification CT (vCT) were included as a training dataset and the other independent 10 pairs of CTs were included as a testing dataset. The vCTs usually were taken 2 weeks after the iCTs. The synthetic CTs (sCTs) were generated by warping the vCTs according to the DVFs generated by the pre‐trained model. The image quality of the synthetic CTs was evaluated by measuring the similarity between the iCTs and the sCTs generated by the proposed methods and the conventional DIR approaches, respectively. Per‐voxel absolute CT‐number‐difference volume histogram (CDVH) and MAE were used as the evaluation metrics. The time to generate the sCTs was also recorded and compared quantitatively. Contours were propagated using the derived DVFs and evaluated with SSIM. Forward dose calculations were done on the sCTs and the corresponding iCTs. Dose volume histograms (DVHs) were generated based on dose distributions on both iCTs and sCTs generated by two models, respectively. The clinically relevant DVH indices were derived for comparison. The resulted dose distributions were also compared using 3D Gamma analysis with thresholds of 3 mm/3%/10% and 2 mm/2%/10%, respectively.ResultsThe two models (wMAE and M+S) achieved a speed of 263.7±163 / 265.8±190 ms and a MAE of 13.15±3.8 / 17.52±5.8 HU for the testing dataset, respectively. The average SSIM scores of 0.987±0.006 and 0.988±0.004 were achieved by the two proposed models, respectively. For both models, CDVH of a typical patient showed that less than 5% of the voxels had a per‐voxel absolute CT‐number‐difference larger than 55 HU. The dose distribution calculated based on a typical sCT showed differences of ≤2cGy[RBE] for clinical target volume (CTV) D95 and D5, within ±0.06% for total lung V5, ≤1.5cGy[RBE] for heart and esophagus Dmean, and ≤6cGy[RBE] for cord Dmax compared to the dose distribution calculated based on the iCT. The good average 3D Gamma passing rates (> 96% for 3 mm/3%/10% and > 94% for 2 mm/2%/10%, respectively) were also observed.ConclusionA deep neural network‐based DIR approach was proposed and has been shown to be reasonably accurate and efficient to register the initial CTs and verification CTs in lung cancer.
Self-expanding Transcatheter vs Surgical Aortic Valve Replacement in Intermediate-Risk Patients

JAMA Cardiology | August 24, 2022 | Volume: 7 | Issue: 10 | Pages: 1000

10.1001/jamacardio.2022.2695 | PMID 36001335

Importance In patients with severe aortic valve stenosis at intermediate surgical risk, transcatheter aortic valve replacement (TAVR) with a self-expanding supra-annular valve was noninferior to surgery for all-cause mortality or disabling stroke at 2 years. Comparisons of longer-term clinical and hemodynamic outcomes in these patients are limited. Objective To report prespecified secondary 5-year outcomes from the Symptomatic Aortic Stenosis in Intermediate Risk Subjects Who Need Aortic Valve Replacement (SURTAVI) randomized clinical trial. Design, Setting, and Participants SURTAVI is a prospective randomized, unblinded clinical trial. Randomization was stratified by investigational site and need for revascularization determined by the local heart teams. Patients with severe aortic valve stenosis deemed to be at intermediate risk of 30-day surgical mortality were enrolled at 87 centers from June 19, 2012, to June 30, 2016, in Europe and North America. Analysis took place between August and October 2021. Intervention Patients were randomized to TAVR with a self-expanding, supra-annular transcatheter or a surgical bioprosthesis. Main Outcomes and Measures The prespecified secondary end points of death or disabling stroke and other adverse events and hemodynamic findings at 5 years. An independent clinical event committee adjudicated all serious adverse events and an independent echocardiographic core laboratory evaluated all echocardiograms at 5 years. Results A total of 1660 individuals underwent an attempted TAVR (n = 864) or surgical (n = 796) procedure. The mean (SD) age was 79.8 (6.2) years, 724 (43.6%) were female, and the mean (SD) Society of Thoracic Surgery Predicted Risk of Mortality score was 4.5% (1.6%). At 5 years, the rates of death or disabling stroke were similar (TAVR, 31.3% vs surgery, 30.8%; hazard ratio, 1.02 [95% CI, 0.85-1.22]; P = .85). Transprosthetic gradients remained lower (mean [SD], 8.6 [5.5] mm Hg vs 11.2 [6.0] mm Hg; P < .001) and aortic valve areas were higher (mean [SD], 2.2 [0.7] cm 2 vs 1.8 [0.6] cm 2 ; P < .001) with TAVR vs surgery. More patients had moderate/severe paravalvular leak with TAVR than surgery (11 [3.0%] vs 2 [0.7%]; risk difference, 2.37% [95% CI, 0.17%- 4.85%]; P = .05). New pacemaker implantation rates were higher for TAVR than surgery at 5 years (289 [39.1%] vs 94 [15.1%]; hazard ratio, 3.30 [95% CI, 2.61-4.17]; log-rank P < .001), as were valve reintervention rates (27 [3.5%] vs 11 [1.9%]; hazard ratio, 2.21 [95% CI, 1.10-4.45]; log-rank P = .02), although between 2 and 5 years only 6 patients who underwent TAVR and 7 who underwent surgery required a reintervention. Conclusions and Relevance Among intermediate-risk patients with symptomatic severe aortic stenosis, major clinical outcomes at 5 years were similar for TAVR and surgery. TAVR was associated with superior hemodynamic valve performance but also with more paravalvular leak and valve reinterventions.
Results of subset analyses on overall survival (OS) from study CA184-043: Ipilimumab (Ipi) versus placebo (Pbo) in post-docetaxel metastatic castration-resistant prostate cancer (mCRPC).

Journal of Clinical Oncology | February 24, 2017 | Volume: 32 | Issue: 4_suppl | Pages: 2-2

10.1200/jco.2014.32.4_suppl.2

2 Background: The CA184-043 phase 3 study did not reach statistical significance for its primary endpoint of OS (HR=0.85, p=0.053). However, antitumor activity was observed in other efficacy endpoints, including progression-free survival. Prespecified subset analyses were performed to understand if any prognostic features may identify mCRPC patients (pts) more likely to benefit from Ipi treatment. Methods: 799 pts were randomized to receive a single dose of radiotherapy (RT) followed by either Ipi (N=399) or Pbo (N=400). Prespecified subset analyses based on Kaplan-Meier/Cox methodology were performed using known prognostic factors for OS in mCRPC. Results: Prespecified subset analyses suggested that Ipi may be more active in pts with favorable prognostic factors, including no visceral disease, alkaline phosphatase <1.5 ULN, and hemoglobin ≥11 g/dL (Table). The safety profile in this study was consistent with previous reports of Ipi. Conclusions: Based on these subset analyses, Ipi added to RT appears to have greater activity than RT alone in pts with a favorable prognostic profile. These results support continued investigation of Ipi in the ongoing CA184-095 study in chemotherapy-naive mCRPC pts. Clinical trial information: NCT00861614. [Table: see text]