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Juan-Cruz C, Stam B, Rossi M, Belderbos J, Sonke JJ. Baseline shift corrections towards the heart: External validation of the impact on survival in early-stage NSCLC patients. Radiother Oncol 2024; 195:110214. [PMID: 38458257 DOI: 10.1016/j.radonc.2024.110214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 02/02/2024] [Accepted: 03/01/2024] [Indexed: 03/10/2024]
Abstract
PURPOSE To externally validate Johnson-Hart et al. findings: the association of tumor baseline shifts towards the heart with overall survival (OS) in SBRT for NSCLC. Further analysis included investigating the presence of interfractional heart baseline shifts and the association of OS with heart dose change during treatment. METHODS Data from 416 SBRT early-stage NSCLC patients was collected. Pearson's correlations (PCCs) between clinical variables and treatment-averaged tumor shifts towards/away from the heart were explored. Validation of published multivariable Cox model was performed. PCCs between heart and tumor baseline shifts were analyzed. Dose accumulation was performed following daily CBCT-to-pCT deformable registration. Maximum heart dose (D0) was computed for planned and accumulated doses. Differences in OS according to shifts towards/away from the heart or D0 increase/decrease were analyzed. Significant D0 differences between patients with D0 increase/decrease and different tumor locations were explored. RESULTS Tumor shifts towards/away from the heart showed no significant association with OS (p = 0.91). Distance between PTV and heart correlated significantly (PCC = 0.18) with shifts to the heart. Cox model did not validate in our cohort. Heart presented baseline shifts positively correlated with tumor baseline shifts in all three directions (PCC ≥ 0.38; p < 0.001). Counterintuitively, patients experiencing increased D0 during treatment showed significantly better OS (p = 0.0077). Upper-lobe tumor patients with increased D0 had lower D0 than those with decreased D0 (right-upper-lobe p ≤ 0.018). CONCLUSIONS In our SBRT cohort, the shifts towards the heart were not associated with worse OS. Moderate correlations were found between tumor and heart baseline shifts in each direction. Moreover, the distance between the PTV and the heart showed a significant correlation with shifts to the heart.
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Affiliation(s)
- Celia Juan-Cruz
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Barbara Stam
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Maddalena Rossi
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - José Belderbos
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Jan-Jakob Sonke
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
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2
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Herr DJ, Yin H, Bergsma D, Dragovic AF, Matuszak M, Grubb M, Dominello M, Movsas B, Kestin LL, Boike T, Bhatt A, Hayman JA, Jolly S, Schipper M, Paximadis P. Factors associated with acute esophagitis during radiation therapy for lung cancer. Radiother Oncol 2024; 197:110349. [PMID: 38815695 DOI: 10.1016/j.radonc.2024.110349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 04/30/2024] [Accepted: 05/22/2024] [Indexed: 06/01/2024]
Abstract
INTRODUCTION Limiting acute esophagitis remains a clinical challenge during the treatment of locally advanced non-small cell lung cancer (NSCLC). METHODS Demographic, dosimetric, and acute toxicity data were prospectively collected for patients undergoing definitive radiation therapy +/- chemotherapy for stage II-III NSCLC from 2012 to 2022 across a statewide consortium. Logistic regression models were used to characterize the risk of grade 2 + and 3 + esophagitis as a function of dosimetric and clinical covariates. Multivariate regression models were fitted to predict the 50 % risk of grade 2 esophagitis and 3 % risk of grade 3 esophagitis. RESULTS Of 1760 patients, 84.2 % had stage III disease and 85.3 % received concurrent chemotherapy. 79.2 % of patients had an ECOG performance status ≤ 1. Overall rates of acute grade 2 + and 3 + esophagitis were 48.4 % and 2.2 %, respectively. On multivariate analyses, performance status, mean esophageal dose (MED) and minimum dose to the 2 cc of esophagus receiving the highest dose (D2cc) were significantly associated with grade 2 + and 3 + esophagitis. Concurrent chemotherapy was associated with grade 2 + but not grade 3 + esophagitis. For all patients, MED of 29 Gy and D2cc of 61 Gy corresponded to a 3 % risk of acute grade 3 + esophagitis. For patients receiving chemotherapy, MED of 22 Gy and D2cc of 50 Gy corresponded to a 50 % risk of acute grade 2 + esophagitis. CONCLUSIONS Performance status, concurrent chemotherapy, MED and D2cc are associated with acute esophagitis during definitive treatment of NSCLC. Models that quantitatively account for these factors can be useful in individualizing radiation plans.
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Affiliation(s)
- Daniel J Herr
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States.
| | - Huiying Yin
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States
| | - Derek Bergsma
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States; St. Mary's Hospital, Lacks Cancer Center, Grand Rapids, MI, United States
| | - Aleksandar F Dragovic
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States; Department of Radiation Oncology, Brighton Center for Specialty Care, Brighton, MI, United States
| | - Martha Matuszak
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States
| | - Margaret Grubb
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States
| | - Michael Dominello
- Department of Radiation Oncology, Karmanos Cancer Institute, Detroit, MI, United States
| | - Benjamin Movsas
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, United States
| | - Larry L Kestin
- MHP Radiation Oncology Institute/GenesisCare USA, Farmington Hills, MI, United States
| | - Thomas Boike
- MHP Radiation Oncology Institute/GenesisCare USA, Farmington Hills, MI, United States
| | - Amit Bhatt
- Department of Radiation Oncology, Karmanos Cancer Institute at McLaren Greater Lansing, Lansing, MI, United States
| | - James A Hayman
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States
| | - Shruti Jolly
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States
| | - Matthew Schipper
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States; Department of Biostatistics, University of Michigan, Ann Arbor, MI, United States.
| | - Peter Paximadis
- Department of Radiation Oncology, Corewell Health South, St. Joseph, MI, United States
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Walls GM, O'Connor J, Harbinson M, Duane F, McCann C, McKavanagh P, Johnston DI, Giacometti V, McAleese J, Hounsell AR, Cole AJ, Butterworth KT, McGarry CK, Hanna GG, Jain S. The Association of Incidental Radiation Dose to the Heart Base with Overall Survival and Cardiac Events after Curative-intent Radiotherapy for Non-small Cell Lung Cancer: Results from the NI-HEART Study. Clin Oncol (R Coll Radiol) 2024; 36:119-127. [PMID: 38042669 DOI: 10.1016/j.clon.2023.11.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/10/2023] [Accepted: 11/06/2023] [Indexed: 12/04/2023]
Abstract
AIMS Cardiac disease is a dose-limiting toxicity in non-small cell lung cancer radiotherapy. The dose to the heart base has been associated with poor survival in multiple institutional and clinical trial datasets using unsupervised, voxel-based analysis. Validation has not been undertaken in a cohort with individual patient delineations of the cardiac base or for the endpoint of cardiac events. The purpose of this study was to assess the association of heart base radiation dose with overall survival and the risk of cardiac events with individual heart base contours. MATERIALS AND METHODS Patients treated between 2015 and 2020 were reviewed for baseline patient, tumour and cardiac details and both cancer and cardiac outcomes as part of the NI-HEART study. Three cardiologists verified cardiac events including atrial fibrillation, heart failure and acute coronary syndrome. Cardiac substructure delineations were completed using a validated deep learning-based autosegmentation tool and a composite cardiac base structure was generated. Cox and Fine-Gray regressions were undertaken for the risk of death and cardiac events. RESULTS Of 478 eligible patients, most received 55 Gy/20 fractions (96%) without chemotherapy (58%), planned with intensity-modulated radiotherapy (71%). Pre-existing cardiovascular morbidity was common (78% two or more risk factors, 46% one or more established disease). The median follow-up was 21.1 months. Dichotomised at the median, a higher heart base Dmax was associated with poorer survival on Kaplan-Meier analysis (20.2 months versus 28.3 months; hazard ratio 1.40, 95% confidence interval 1.14-1.75, P = 0.0017) and statistical significance was retained in multivariate analyses. Furthermore, heart base Dmax was associated with pooled cardiac events in a multivariate analysis (hazard ratio 1.75, 95% confidence interval 1.03-2.97, P = 0.04). CONCLUSIONS Heart base Dmax was associated with the rate of death and cardiac events after adjusting for patient, tumour and cardiovascular factors in the NI-HEART study. This validates the findings from previous unsupervised analytical approaches. The heart base could be considered as a potential sub-organ at risk towards reducing radiation cardiotoxicity.
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Affiliation(s)
- G M Walls
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK.
| | - J O'Connor
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - M Harbinson
- Department of Cardiology, Belfast Health & Social Care Trust, Belfast, UK; Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - F Duane
- St. Luke's Radiation Oncology Network, St. Luke's Hospital, Dublin, Ireland; Trinity St James's Cancer Institute, St. James's Hospital, Dublin, Ireland
| | - C McCann
- Department of Cardiology, Belfast Health & Social Care Trust, Belfast, UK
| | - P McKavanagh
- Department of Cardiology, Ulster Hospital, South Eastern Health & Social Care Trust, Dundonald, UK
| | - D I Johnston
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK
| | - V Giacometti
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - J McAleese
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK
| | - A R Hounsell
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - A J Cole
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - K T Butterworth
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - C K McGarry
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - G G Hanna
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - S Jain
- Cancer Centre Belfast City Hospital, Belfast Health & Social Care Trust, Belfast, UK; Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
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Yegya-Raman N, Kegelman TP, Ho Lee S, Kallan MJ, Kim KN, Natarajan J, Deek MP, Zou W, O'Reilly SE, Zhang Z, Levin W, Cengel K, Kao G, Cohen RB, Sun LL, Langer CJ, Aggarwal C, Singh AP, O'Quinn R, Ky B, Apte A, Deasy J, Xiao Y, Berman AT, Jabbour SK, Feigenberg SJ. Death without progression as an endpoint to describe cardiac radiation effects in locally advanced non-small cell lung cancer. Clin Transl Radiat Oncol 2023; 39:100581. [PMID: 36691564 PMCID: PMC9860414 DOI: 10.1016/j.ctro.2023.100581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/03/2023] [Accepted: 01/11/2023] [Indexed: 01/14/2023] Open
Abstract
Background and purpose Prior studies have examined associations of cardiovascular substructure dose with overall survival (OS) or cardiac events after chemoradiotherapy (CRT) for non-small cell lung cancer (NSCLC). Herein, we investigate an alternative endpoint, death without cancer progression (DWP), which is potentially more specific than OS and more sensitive than cardiac events for understanding CRT toxicity. Materials and methods We retrospectively reviewed records of 187 patients with locally advanced or oligometastatic NSCLC treated with definitive CRT from 2008 to 2016 at a single institution. Dosimetric parameters to the heart, lung, and ten cardiovascular substructures were extracted. Charlson Comorbidity Index (CCI), excluding NSCLC diagnosis, was used to stratify patients into CCI low (0-2; n = 66), CCI intermediate (3-4; n = 78), and CCI high (≥5; n = 43) groups. Primary endpoint was DWP, modeled with competing risk regression. Secondary endpoints included OS. An external cohort consisted of 140 patients from another institution. Results Median follow-up was 7.3 years for survivors. Death occurred in 143 patients (76.5 %), including death after progression in 118 (63.1 %) and DWP in 25 (13.4 %). On multivariable analysis, increasing CCI stratum and mean heart dose were associated with DWP. For mean heart dose ≥ 10 Gy vs < 10 Gy, DWP was higher (5-year rate, 16.9 % vs 6.7 %, p = 0.04) and OS worse (median, 22.9 vs 34.1 months, p < 0.001). Ventricle (left, right, and bilateral) and pericardial but not atrial substructure dose were associated with DWP, whereas all three were inversely associated with OS. Cutpoint analysis identified right ventricle mean dose ≥ 5.5 Gy as a predictor of DWP. In the external cohort, we confirmed an association of ventricle, but not atrial, dose with DWP. Conclusion Cardiovascular substructure dose showed distinct associations with DWP. Future cardiotoxicity studies in NSCLC could consider DWP as an endpoint.
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Affiliation(s)
- Nikhil Yegya-Raman
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Timothy P. Kegelman
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Sang Ho Lee
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael J. Kallan
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Kristine N. Kim
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Jyotsna Natarajan
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Matthew P. Deek
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, United States
| | - Wei Zou
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Shannon E. O'Reilly
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Zheng Zhang
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - William Levin
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Keith Cengel
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Gary Kao
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Roger B. Cohen
- Division of Hematology and Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Lova L. Sun
- Division of Hematology and Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Corey J. Langer
- Division of Hematology and Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Charu Aggarwal
- Division of Hematology and Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Aditi P. Singh
- Division of Hematology and Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Rupal O'Quinn
- Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Bonnie Ky
- Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Aditya Apte
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Joseph Deasy
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Ying Xiao
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Abigail T. Berman
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Salma K. Jabbour
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, United States
| | - Steven J. Feigenberg
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Vivekanandan S, Fenwick JD, Counsell N, Panakis N, Stuart R, Higgins GS, Hawkins MA. Associations between cardiac irradiation and survival in patients with non-small cell lung cancer: Validation and new discoveries in an independent dataset. Radiother Oncol 2021; 165:119-125. [PMID: 34718053 DOI: 10.1016/j.radonc.2021.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 09/11/2021] [Accepted: 10/19/2021] [Indexed: 12/25/2022]
Abstract
INTRODUCTION In 'IDEAL-6' patients (N = 78) treated for locally-advanced non-small-cell lung cancer using isotoxically dose-escalated radiotherapy, overall survival (OS) was associated more strongly with VLAwall-64-73-EQD2, the left atrial (LA) wall volume receiving 64-73 Gy equivalent dose in 2 Gy fractions (EQD2), than with whole-heart irradiation measures. Here we test this in an independent cohort 'OX-RT' (N = 64) treated routinely. METHODS Using Cox regression analysis we assessed how strongly OS was associated with VLAwall-64-73-EQD2, with whole-heart volumes receiving 64-73 Gy EQD2 or doses above 10-to-70 Gy thresholds, and with principal components of whole-heart dose-distributions. Additionally, we tested associations between OS and volumes of cardiac substructures receiving dose-ranges described by whole-heart principal components significantly associated with OS. RESULTS In univariable analyses of OX-RT, OS was associated more strongly with VLAwall-64-73-EQD2 than with whole-heart irradiation measures, but more strongly still with VAortV-29-38-EQD2, the volume of the aortic valve region receiving 29-38 Gy EQD2. The best multivariable OS model included LA wall and aortic valve region mean doses, and the aortic valve volume receiving ≥38 Gy EQD2, VAortV-38-EQD2. In a subsidiary analysis of IDEAL-6, the best multivariable model included VLAwall-64-73-EQD2, VAortV-29-38-EQD2, VAortV-38-EQD2 and mean aortic valve dose. CONCLUSION We propose reducing heart mean doses to the lowest levels possible while meeting protocol dose-limits for lung, oesophagus, proximal bronchial tree, cord and brachial plexus. This in turn achieves large reductions in VAortV-29-38-EQD2 and VLAwall-64-73-EQD2, and we plan to closely monitor patients with values of these measures still >0% (their median value in OX-RT) following reduction.
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Affiliation(s)
| | - John D Fenwick
- Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, UK
| | - Nicholas Counsell
- Cancer Research UK & University College London Cancer Trials Centre, London, UK
| | | | | | - Geoff S Higgins
- Oxford University Hospital NHS FT, UK; MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, UK
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Anderson JD, Hu J, Li J, Schild SE, Fatyga M. Impact of Cardiac Dose on Overall Survival in Lung Stereotactic Body Radiotherapy (SBRT) Compared to Conventionally Fractionated Radiotherapy for Locally Advanced Non-Small Cell Lung Cancer (LA-NSCLC). JOURNAL OF CANCER THERAPY 2021; 12:409-423. [PMID: 34367717 PMCID: PMC8341170 DOI: 10.4236/jct.2021.127036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To examine possible association between heart irradiation and Overall Survival (OS) in lung SBRT patients and to compare observed associations with cardiac toxicity models previously derived in LA-NSCLC patient studies. MATERIALS AND METHODS 197 Patients treated with lung SBRT at Mayo Clinic Arizona were selected for this IRB-approved study. Multivariate Cox model with Akaike Information Criterion (AIC) was used to select patient specific covariates associated with OS. Heart dosimetry was represented by VD indices, which is a percentage of volume exposed to dose D or greater. Multivariate Cox models with patient specific covariates and single VD index per model was used to find a range of doses which were predictive for OS. A digital subdivision of the heart was further used to determine the spatial distribution of doses which were predictive for OS. A coarse subdivision divided heart into 4 segments, while the fine subdivision divided heart into 64 segments. Knowledge constrained Fused Lasso operator was used to derive a more complete model which correlated heart dosimetry with OS. Results of statistical analysis were compared to predictions of a model of cardiac toxicity in LA-NSCLC patients. RESULTS Higher age (p < 0.001), higher stage (p < 0.001) and squamous cell histology (p = 0.001) were associated with reduced OS. Whole heart DVH analysis did not reveal associations between heart irradiation and reduced OS. Coarse subdivision of the heart into four segments revealed that the irradiation of two inferior segments of the heart with low doses was associated with reduced OS, V 2Gy in the right-inferior segment (HR = 1.012/1%, p = 0.02), and V 1Gy in the left-inferior segment (HR = 1.01/1%, p = 0.04). Maximum dose in the right-inferior segment of the heart was also associated with reduced OS (HR = 1.02/Gy, p = 0.02). Fine subdivision of the heart into 64 segments revealed that approximately 25% of heart volume in the inferior part of the heart (15/64 segments), when irradiated to doses in the 1 Gy - 5 Gy range, were predictive for reduced OS (HR = 1.01/1%, p = 0.01). A previously derived model of cardiac toxicity in LA-NSCLC patients did not predict a reduction of OS due to heart irradiation in lung SBRT patients, because of relatively low doses to the heart in most lung SBRT patients. CONCLUSIONS Doses lower than 5 Gy in the inferior segments of the heart may be associated with reduced overall survival in patients treated for lung lesions with SBRT. Stage and histology of the disease, as well as patients' age, were also associated with overall survival. Comparisons of cardiac toxicity patterns in LA-NSCLC patients and lung SBRT patients suggest different etiology of cardiac toxicity in the two groups.
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Affiliation(s)
| | - Jiuyun Hu
- School of Computing, Informatics, and Decision Systems Engineering, Tempe, Arizona, USA
| | - Jing Li
- School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Steven E. Schild
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA
| | - Mirek Fatyga
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA
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