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Natesan D, Eisenstein EL, Thomas SM, Eclov NCW, Dalal NH, Stephens SJ, Malicki M, Shields S, Cobb A, Mowery YM, Niedzwiecki D, Tenenbaum JD, Palta M, Hong JC. Health Care Cost Reductions with Machine Learning-Directed Evaluations during Radiation Therapy - An Economic Analysis of a Randomized Controlled Study. NEJM AI 2024; 1:10.1056/aioa2300118. [PMID: 38586278 PMCID: PMC10997376 DOI: 10.1056/aioa2300118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
BACKGROUND Machine learning (ML) may cost-effectively direct health care by identifying patients most likely to benefit from preventative interventions to avoid negative and expensive outcomes. System for High-Intensity Evaluation During Radiation Therapy (SHIELD-RT; NCT04277650) was a single-institution, randomized controlled study in which electronic health record-based ML accurately identified patients at high risk for acute care (emergency visit or hospitalization) during radiotherapy (RT) and targeted them for supplemental clinical evaluations. This ML-directed intervention resulted in decreased acute care utilization. Given the limited prospective data showing the ability of ML to direct interventions cost-efficiently, an economic analysis was performed. METHODS A post hoc economic analysis was conducted of SHIELD-RT that included RT courses from January 7, 2019, to June 30, 2019. ML-identified high-risk courses (≥10% risk of acute care during RT) were randomized to receive standard of care weekly clinical evaluations with ad hoc supplemental evaluations per clinician discretion versus mandatory twice-weekly evaluations. The primary outcome was difference in mean total medical costs during and 15 days after RT. Acute care costs were obtained via institutional cost accounting. Physician and intervention costs were estimated via Medicare and Medicaid data. Negative binomial regression was used to estimate cost outcomes after adjustment for patient and disease factors. RESULTS A total of 311 high-risk RT courses among 305 patients were randomized to the standard (n=157) or the intervention (n=154) group. Unadjusted mean intervention group supplemental visit costs were $155 per course (95% confidence interval, $142 to $168). The intervention group had fewer acute care visits per course (standard, 0.47; intervention, 0.31; P=0.04). Total mean adjusted costs were $3110 per course for the standard group and $1494 for the intervention group (difference in means, $1616 [95% confidence interval, $1450 to $1783]; P=0.03). CONCLUSIONS In this economic analysis of a randomized controlled, health care ML study, mandatory supplemental evaluations for ML-identified high-risk patients were associated with both reduced total medical costs and improved clinical outcomes. Further study is needed to determine whether economic results are generalizable. (Funded in part by The Duke Endowment, The Conquer Cancer Foundation, the Duke Department of Radiation Oncology, and the National Cancer Institute of the National Institutes of Health [R01CA277782]; ClinicalTrials.gov number, NCT04277650.).
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Affiliation(s)
- Divya Natesan
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC
- Department of Radiation Oncology, Duke University, Durham, NC
| | | | - Samantha M Thomas
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | | | - Nicole H Dalal
- Department of Radiation Oncology, Duke University, Durham, NC
| | | | - Mary Malicki
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Stacey Shields
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Alyssa Cobb
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Yvonne M Mowery
- Department of Radiation Oncology, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | - Donna Niedzwiecki
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | | | - Manisha Palta
- Department of Radiation Oncology, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | - Julian C Hong
- Department of Radiation Oncology, University of California, San Francisco, San Francisco
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco
- UCSF-UC Berkeley Joint Program in Computational Precision Health, San Francisco, San Francisco
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Hong JC, Patel P, Eclov NCW, Stephens SJ, Mowery YM, Tenenbaum JD, Palta M. Healthcare provider evaluation of machine learning-directed care: reactions to deployment on a randomised controlled study. BMJ Health Care Inform 2023; 30:bmjhci-2022-100674. [PMID: 36764680 PMCID: PMC9923272 DOI: 10.1136/bmjhci-2022-100674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 01/28/2023] [Indexed: 02/12/2023] Open
Abstract
OBJECTIVES Clinical artificial intelligence and machine learning (ML) face barriers related to implementation and trust. There have been few prospective opportunities to evaluate these concerns. System for High Intensity EvaLuation During Radiotherapy (NCT03775265) was a randomised controlled study demonstrating that ML accurately directed clinical evaluations to reduce acute care during cancer radiotherapy. We characterised subsequent perceptions and barriers to implementation. METHODS An anonymous 7-question Likert-type scale survey with optional free text was administered to multidisciplinary staff focused on workflow, agreement with ML and patient experience. RESULTS 59/71 (83%) responded. 81% disagreed/strongly disagreed their workflow was disrupted. 67% agreed/strongly agreed patients undergoing intervention were high risk. 75% agreed/strongly agreed they would implement the ML approach routinely if the study was positive. Free-text feedback focused on patient education and ML predictions. CONCLUSIONS Randomised data and firsthand experience support positive reception of clinical ML. Providers highlighted future priorities, including patient counselling and workflow optimisation.
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Affiliation(s)
- Julian C Hong
- Department of Radiation Oncology, University of California San Francisco, San Francisco, California, USA .,Bakar Computational Health Sciences Institute, University of California San Francisco, San Francisco, California, USA.,Joint Program in Computational Precision Health, UCSF-UC Berkeley, San Francisco, California, USA
| | - Pranalee Patel
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
| | - Neville C W Eclov
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
| | - Sarah J Stephens
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
| | - Yvonne M Mowery
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA,Department of Head and Neck Surgery & Communication Sciences, Duke University, Durham, North Carolina, USA
| | - Jessica D Tenenbaum
- Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina, USA
| | - Manisha Palta
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
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Hong JC, Eclov NCW, Stephens SJ, Mowery YM, Palta M. Implementation of machine learning in the clinic: challenges and lessons in prospective deployment from the System for High Intensity EvaLuation During Radiation Therapy (SHIELD-RT) randomized controlled study. BMC Bioinformatics 2022; 23:408. [PMID: 36180836 PMCID: PMC9526253 DOI: 10.1186/s12859-022-04940-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 12/02/2022] Open
Abstract
Background Artificial intelligence (AI) and machine learning (ML) have resulted in significant enthusiasm for their promise in healthcare. Despite this, prospective randomized controlled trials and successful clinical implementation remain limited. One clinical application of ML is mitigation of the increased risk for acute care during outpatient cancer therapy. We previously reported the results of the System for High Intensity EvaLuation During Radiation Therapy (SHIELD-RT) study (NCT04277650), which was a prospective, randomized quality improvement study demonstrating that ML based on electronic health record (EHR) data can direct supplemental clinical evaluations and reduce the rate of acute care during cancer radiotherapy with and without chemotherapy. The objective of this study is to report the workflow and operational challenges encountered during ML implementation on the SHIELD-RT study. Results Data extraction and manual review steps in the workflow represented significant time commitments for implementation of clinical ML on a prospective, randomized study. Barriers include limited data availability through the standard clinical workflow and commercial products, the need to aggregate data from multiple sources, and logistical challenges from altering the standard clinical workflow to deliver adaptive care. Conclusions The SHIELD-RT study was an early randomized controlled study which enabled assessment of barriers to clinical ML implementation, specifically those which leverage the EHR. These challenges build on a growing body of literature and may provide lessons for future healthcare ML adoption. Trial registration: NCT04277650. Registered 20 February 2020. Retrospectively registered quality improvement study.
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Hong JC, Eclov NCW, Dalal NH, Thomas SM, Stephens SJ, Malicki M, Shields S, Cobb A, Mowery YM, Niedzwiecki D, Tenenbaum JD, Palta M. System for High-Intensity Evaluation During Radiation Therapy (SHIELD-RT): A Prospective Randomized Study of Machine Learning–Directed Clinical Evaluations During Radiation and Chemoradiation. J Clin Oncol 2020; 38:3652-3661. [DOI: 10.1200/jco.20.01688] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
PURPOSE Patients undergoing outpatient radiotherapy (RT) or chemoradiation (CRT) frequently require acute care (emergency department evaluation or hospitalization). Machine learning (ML) may guide interventions to reduce this risk. There are limited prospective studies investigating the clinical impact of ML in health care. The objective of this study was to determine whether ML can identify high-risk patients and direct mandatory twice-weekly clinical evaluation to reduce acute care visits during treatment. PATIENTS AND METHODS During this single-institution randomized quality improvement study (ClinicalTrials.gov identifier: NCT04277650 ), 963 outpatient adult courses of RT and CRT started from January 7 to June 30, 2019, were evaluated by an ML algorithm. Among these, 311 courses identified by ML as high risk (> 10% risk of acute care during treatment) were randomized to standard once-weekly clinical evaluation (n = 157) or mandatory twice-weekly evaluation (n = 154). Both arms allowed additional evaluations on the basis of clinician discretion. The primary end point was the rate of acute care visits during RT. Model performance was evaluated using receiver operating characteristic area under the curve (AUC) and decile calibration plots. RESULTS Twice-weekly evaluation reduced rates of acute care during treatment from 22.3% to 12.3% (difference, −10.0%; 95% CI, −18.3 to −1.6; relative risk, 0.556; 95% CI, 0.332 to 0.924; P = .02). Low-risk patients had a 2.7% acute care rate. Model discrimination was good in high- and low-risk patients undergoing standard once-weekly evaluation (AUC, 0.851). CONCLUSION In this prospective randomized study, ML accurately triaged patients undergoing RT and CRT, directing clinical management with reduced acute care rates versus standard of care. This prospective study demonstrates the potential benefit of ML in health care and offers opportunities to enhance care quality and reduce health care costs.
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Affiliation(s)
- Julian C. Hong
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA
- Department of Radiation Oncology, Duke University, Durham, NC
| | | | - Nicole H. Dalal
- Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Samantha M. Thomas
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | | | - Mary Malicki
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Stacey Shields
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Alyssa Cobb
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Yvonne M. Mowery
- Department of Radiation Oncology, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | - Donna Niedzwiecki
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
| | | | - Manisha Palta
- Department of Radiation Oncology, Duke University, Durham, NC
- Duke Cancer Institute, Duke University, Durham, NC
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Gensheimer MF, Hong JC, Chang-Halpenny C, Zhu H, Eclov NCW, To J, Murphy JD, Wakelee HA, Neal JW, Le QT, Hara WY, Quon A, Maxim PG, Graves EE, Olson MR, Diehn M, Loo BW. Mid-radiotherapy PET/CT for prognostication and detection of early progression in patients with stage III non-small cell lung cancer. Radiother Oncol 2017; 125:338-343. [PMID: 28830717 DOI: 10.1016/j.radonc.2017.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 05/22/2017] [Accepted: 08/05/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE Pre- and mid-radiotherapy FDG-PET metrics have been proposed as biomarkers of recurrence and survival in patients treated for stage III non-small cell lung cancer. We evaluated these metrics in patients treated with definitive radiation therapy (RT). We also evaluated outcomes after progression on mid-radiotherapy PET/CT. MATERIAL AND METHODS Seventy-seven patients treated with RT with or without chemotherapy were included in this retrospective study. Primary tumor and involved nodes were delineated. PET metrics included metabolic tumor volume (MTV), total lesion glycolysis (TLG), and SUVmax. For mid-radiotherapy PET, both absolute value of these metrics and percentage decrease were analyzed. The influence of PET metrics on time to death, local recurrence, and regional/distant recurrence was assessed using Cox regression. RESULTS 91% of patients had concurrent chemotherapy. Median follow-up was 14months. None of the PET metrics were associated with overall survival. Several were positively associated with local recurrence: pre-radiotherapy MTV, and mid-radiotherapy MTV and TLG (p=0.03-0.05). Ratio of mid- to pre-treatment SUVmax was associated with regional/distant recurrence (p=0.02). 5/77 mid-radiotherapy scans showed early out-of-field progression. All of these patients died. CONCLUSIONS Several PET metrics were associated with risk of recurrence. Progression on mid-radiotherapy PET/CT was a poor prognostic factor.
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Affiliation(s)
- Michael F Gensheimer
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA.
| | - Julian C Hong
- Department of Radiation Oncology, Stanford University, USA; Department of Radiation Oncology, Duke University, Durham, USA
| | - Christine Chang-Halpenny
- Department of Radiation Oncology, Stanford University, USA; Department of Radiation Oncology, cCARE, Fresno, USA
| | - Hui Zhu
- Department of Radiation Oncology, Stanford University, USA; Department of Radiation Oncology, Shandong Cancer Hospital Affiliated to Shandong University, Jinan, China
| | - Neville C W Eclov
- Department of Radiation Oncology, Stanford University, USA; University of Chicago, USA
| | - Jacqueline To
- Department of Radiation Oncology, Stanford University, USA; University of Colorado, USA
| | - James D Murphy
- Department of Radiation Oncology, Stanford University, USA; Department of Radiation Medicine and Applied Sciences, University of California San Diego, USA
| | - Heather A Wakelee
- Stanford Cancer Institute, Stanford University School of Medicine, USA; Department of Medicine, Division of Oncology, Stanford University, USA
| | - Joel W Neal
- Stanford Cancer Institute, Stanford University School of Medicine, USA; Department of Medicine, Division of Oncology, Stanford University, USA
| | - Quynh-Thu Le
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA
| | - Wendy Y Hara
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA
| | - Andrew Quon
- Department of Nuclear Medicine, University of California Los Angeles, USA
| | - Peter G Maxim
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA
| | - Michael R Olson
- Department of Radiation Oncology, Stanford University, USA; Florida Radiation Oncology Group, Baptist Medical Center, Jacksonville, USA
| | - Maximilian Diehn
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, USA.
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University, USA; Stanford Cancer Institute, Stanford University School of Medicine, USA.
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Newman AM, Bratman SV, To J, Wynne JF, Eclov NCW, Modlin LA, Liu CL, Neal JW, Wakelee HA, Merritt RE, Shrager JB, Loo BW, Alizadeh AA, Diehn M. An ultrasensitive method for quantitating circulating tumor DNA with broad patient coverage. Nat Med 2014; 20:548-54. [PMID: 24705333 PMCID: PMC4016134 DOI: 10.1038/nm.3519] [Citation(s) in RCA: 1490] [Impact Index Per Article: 149.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 11/06/2013] [Indexed: 02/06/2023]
Abstract
Circulating tumor DNA (ctDNA) represents a promising biomarker for noninvasive assessment of cancer burden, but existing methods have insufficient sensitivity or patient coverage for broad clinical applicability. Here we introduce CAncer Personalized Profiling by deep Sequencing (CAPP-Seq), an economical and ultrasensitive method for quantifying ctDNA. We implemented CAPP-Seq for non-small cell lung cancer (NSCLC) with a design covering multiple classes of somatic alterations that identified mutations in >95% of tumors. We detected ctDNA in 100% of stage II–IV and 50% of stage I NSCLC patients, with 96% specificity for mutant allele fractions down to ~0.02%. Levels of ctDNA significantly correlated with tumor volume, distinguished between residual disease and treatment-related imaging changes, and provided earlier response assessment than radiographic approaches. Finally, we explored biopsy-free tumor screening and genotyping with CAPP-Seq. We envision that CAPP-Seq could be routinely applied clinically to detect and monitor diverse malignancies, thus facilitating personalized cancer therapy.
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Affiliation(s)
- Aaron M Newman
- 1] Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA. [2] Division of Oncology, Department of Medicine, Stanford Cancer Institute, Stanford University, Stanford, California, USA. [3]
| | - Scott V Bratman
- 1] Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA. [2] Department of Radiation Oncology, Stanford University, Stanford, California, USA. [3]
| | - Jacqueline To
- Department of Radiation Oncology, Stanford University, Stanford, California, USA
| | - Jacob F Wynne
- Department of Radiation Oncology, Stanford University, Stanford, California, USA
| | - Neville C W Eclov
- Department of Radiation Oncology, Stanford University, Stanford, California, USA
| | - Leslie A Modlin
- Department of Radiation Oncology, Stanford University, Stanford, California, USA
| | - Chih Long Liu
- 1] Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA. [2] Division of Oncology, Department of Medicine, Stanford Cancer Institute, Stanford University, Stanford, California, USA
| | - Joel W Neal
- Division of Oncology, Department of Medicine, Stanford Cancer Institute, Stanford University, Stanford, California, USA
| | - Heather A Wakelee
- Division of Oncology, Department of Medicine, Stanford Cancer Institute, Stanford University, Stanford, California, USA
| | - Robert E Merritt
- Division of Thoracic Surgery, Department of Cardiothoracic Surgery, Stanford School of Medicine, Stanford University, Stanford, California, USA
| | - Joseph B Shrager
- Division of Thoracic Surgery, Department of Cardiothoracic Surgery, Stanford School of Medicine, Stanford University, Stanford, California, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University, Stanford, California, USA
| | - Ash A Alizadeh
- 1] Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA. [2] Division of Oncology, Department of Medicine, Stanford Cancer Institute, Stanford University, Stanford, California, USA. [3] Division of Hematology, Department of Medicine, Stanford Cancer Institute, Stanford University, Stanford, California, USA
| | - Maximilian Diehn
- 1] Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA. [2] Department of Radiation Oncology, Stanford University, Stanford, California, USA. [3] Stanford Cancer Institute, Stanford University, Stanford, California, USA
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Hong JC, Eclov NCW, Yu Y, Rao AK, Dieterich S, Le QT, Diehn M, Sze DY, Loo BW, Kothary N, Maxim PG. Migration of implanted markers for image-guided lung tumor stereotactic ablative radiotherapy. J Appl Clin Med Phys 2013; 14:4046. [PMID: 23470933 PMCID: PMC5714376 DOI: 10.1120/jacmp.v14i2.4046] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 10/25/2012] [Accepted: 11/02/2012] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to quantify postimplantation migration of percutaneously implanted cylindrical gold seeds (“seeds”) and platinum endovascular embolization coils (“coils”) for tumor tracking in pulmonary stereotactic ablative radiotherapy (SABR). We retrospectively analyzed the migration of markers in 32 consecutive patients with computed tomography scans postimplantation and at simulation. We implanted 147 markers (59 seeds, 88 coils) in or around 34 pulmonary tumors over 32 procedures, with one lesion implanted twice. Marker coordinates were rigidly aligned by minimizing fiducial registration error (FRE), the root mean square of the differences in marker locations for each tumor between scans. To also evaluate whether single markers were responsible for most migration, we aligned with and without the outlier causing the largest FRE increase per tumor. We applied the resultant transformation to all markers. We evaluated migration of individual markers and FRE of each group. Median scan interval was 8 days. Median individual marker migration was 1.28 mm (interquartile range [IQR] 0.78−2.63 mm). Median lesion FRE was 1.56 mm (IQR 0.92−2.95 mm). Outlier identification yielded 1.03 mm median migration (IQR 0.52−2.21 mm) and 1.97 mm median FRE (IQR 1.44−4.32 mm). Outliers caused a mean and median shift in the centroid of 1.22 and 0.80 mm (95th percentile 2.52 mm). Seeds and coils had no statistically significant difference. Univariate analysis suggested no correlation of migration with the number of markers, contact with the chest wall, or time elapsed. Marker migration between implantation and simulation is limited and unlikely to cause geometric miss during tracking. PACS number: 87.57.N‐; 87.57.nm; 87.53.Ly
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Affiliation(s)
- Julian C Hong
- Department of Radiation Oncology, Stanford University, CA, USA
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Liu MB, Eclov NCW, Trakul N, Murphy J, Diehn M, Le QT, Dieterich S, Maxim PG, Loo BW. Clinical impact of dose overestimation by effective path length calculation in stereotactic ablative radiation therapy of lung tumors. Pract Radiat Oncol 2012; 3:294-300. [PMID: 24674401 DOI: 10.1016/j.prro.2012.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/11/2012] [Accepted: 09/17/2012] [Indexed: 02/03/2023]
Abstract
PURPOSE To determine the clinical impact of calculated dose differences between effective path length (EPL) and Monte Carlo (MC) algorithms in stereotactic ablative radiation therapy (SABR) of lung tumors. METHODS AND MATERIALS We retrospectively analyzed the treatment plans and clinical outcomes of 77 consecutive patients treated with SABR for 82 lung tumors between 2003 and 2009 at our institution. Sixty treatments were originally planned using EPL, and 22 using MC. All plans were recalculated for the same beam specifications using MC and EPL, respectively. The doses covering 95%, 50%, and 5% (D95, D50, D5, respectively) of the target volumes were compared between EPL and MC (assumed to be the actual delivered dose), both as physical dose and biologically effective dose. Time to local recurrence was correlated with dose by Cox regression analysis. The relationship between tumor control probability (TCP) and biologically effective dose was determined via logistic regression and used to estimate the TCP decrements due to prescribing by EPL calculations. RESULTS EPL overestimated dose compared with MC in all tumor dose-volume histogram parameters in all plans. The difference was >10% of the MC D95 to the planning target volume and gross tumor volume in 60 of 82 (73%) and 52 of 82 plans (63%), respectively. Local recurrence occurred in 13 of 82 tumors. Controlling for gross tumor volume, higher physical and biologically effective planning target volume D95 correlated significantly with local control (P = .007 and P = .045, respectively). Compared with MC, prescribing based on EPL translated to a median TCP decrement of 4.3% (range, 1.2%-37%) and a >5% decrement in 46% of tumors. CONCLUSIONS Clinical follow-up for local lung tumor control in a sizable cohort of patients treated with SABR demonstrates that EPL overestimates dose by amounts that substantially decrease TCP in a large proportion. EPL algorithms should be avoided for lung tumor SABR.
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Affiliation(s)
- Michael B Liu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Neville C W Eclov
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Nicholas Trakul
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - James Murphy
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Maximilian Diehn
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Quynh-Thu Le
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California
| | - Sonja Dieterich
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Department of Radiation Oncology, University of California, Davis, School of Medicine, Davis, California
| | - Peter G Maxim
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California.
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California.
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