A modified hypoxia-based TCP model to investigate the clinical outcome of stereotactic hypofractionated regimes for early stage non-small-cell lung cancer (NSCLC).
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| Title: | A modified hypoxia-based TCP model to investigate the clinical outcome of stereotactic hypofractionated regimes for early stage non-small-cell lung cancer (NSCLC). |
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| Authors: | Strigari, L.1, Benassi, M.2, Sarnelli, A.2, Polico, R.3, D'Andrea, M.1 |
| Source: | Medical Physics. Jul2012, Vol. 39 Issue 7,Part 1, p4502-4514. 13p. |
| Subjects: | Hypoxemia, Lung cancer treatment, Health outcome assessment, Cancer radiotherapy, Stereotaxic techniques, Clinical trials, Medical publishing |
| Abstract: | Purpose: Stereotactic body radiotherapy (SBRT) has been applied to lung tumors at different stages and sizes with good local tumor control (LC) rates. The linear quadratic model (LQM), in its basic formulation, does not seem to be appropriate to describe the response to radiotherapy for clinical trials, based on a few fractions. Thus, the main aim of this work was to develop a model, which takes into account the hypoxic cells and their reoxygenation. Methods: A parameter named B has been introduced in a modified tumor control probability (TCP) from LQM and linear-quadratic-linear model (LQLM), and represents the fraction of hypoxic cells that survive and become oxygenated after each irradiation. Based on published trials evaluating LC at 3 yr (LC3), values of B were obtained by maximum likelihood minimization between predicted TCP and clinical LC3. Two oxygen enhancement ratio (OER) parameter sets (1 and 2) from literature have been adopted to calculate the B-factors. Initial hypoxic cell fractions (ηh) from 0.05 to 0.50 were assumed. Log-likelihood (L) and Akaike information criterion (AIC) were determined in an independent clinical validation dataset. Results: The B-values of modified TCPs spanned the whole interval from 0 to 1, depending on the fractionation scheme (number of fractions and dose/fraction), showing a maximum (close to 1) at doses/fraction of 8-12 Gy. The B-values calculated using the OER parameter set 1 exhibited a smoother falloff than set 2. An analytical expression was derived to describe the B-value's dependence on the fractionation scheme. The R2-adjusted values varied from 0.63 to 0.67 for LQ models and OER set 1 and from 0.75 to 0.78 for LQ model and OER set 2. Lower values of R2-adjusted were found for LQLM and both OER sets. L and AIC, calculated using a fraction of ηh = 0.15 and the B-value from the authors analytical expression were higher than for other ηh-values, irrespective of model or OER set. Conclusions: The authors model allows to predict the clinical outcome associated with SBRT treatment, taking into account both direct killing and indirect vasculature or stromal damage. [ABSTRACT FROM AUTHOR] |
| Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 78029789 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: A modified hypoxia-based TCP model to investigate the clinical outcome of stereotactic hypofractionated regimes for early stage non-small-cell lung cancer (NSCLC). – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Strigari%2C+L%2E%22">Strigari, L.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Benassi%2C+M%2E%22">Benassi, M.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Sarnelli%2C+A%2E%22">Sarnelli, A.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Polico%2C+R%2E%22">Polico, R.</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22D'Andrea%2C+M%2E%22">D'Andrea, M.</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Jul2012, Vol. 39 Issue 7,Part 1, p4502-4514. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Hypoxemia%22">Hypoxemia</searchLink><br /><searchLink fieldCode="DE" term="%22Lung+cancer+treatment%22">Lung cancer treatment</searchLink><br /><searchLink fieldCode="DE" term="%22Health+outcome+assessment%22">Health outcome assessment</searchLink><br /><searchLink fieldCode="DE" term="%22Cancer+radiotherapy%22">Cancer radiotherapy</searchLink><br /><searchLink fieldCode="DE" term="%22Stereotaxic+techniques%22">Stereotaxic techniques</searchLink><br /><searchLink fieldCode="DE" term="%22Clinical+trials%22">Clinical trials</searchLink><br /><searchLink fieldCode="DE" term="%22Medical+publishing%22">Medical publishing</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: Stereotactic body radiotherapy (SBRT) has been applied to lung tumors at different stages and sizes with good local tumor control (LC) rates. The linear quadratic model (LQM), in its basic formulation, does not seem to be appropriate to describe the response to radiotherapy for clinical trials, based on a few fractions. Thus, the main aim of this work was to develop a model, which takes into account the hypoxic cells and their reoxygenation. Methods: A parameter named B has been introduced in a modified tumor control probability (TCP) from LQM and linear-quadratic-linear model (LQLM), and represents the fraction of hypoxic cells that survive and become oxygenated after each irradiation. Based on published trials evaluating LC at 3 yr (LC3), values of B were obtained by maximum likelihood minimization between predicted TCP and clinical LC3. Two oxygen enhancement ratio (OER) parameter sets (1 and 2) from literature have been adopted to calculate the B-factors. Initial hypoxic cell fractions (ηh) from 0.05 to 0.50 were assumed. Log-likelihood (L) and Akaike information criterion (AIC) were determined in an independent clinical validation dataset. Results: The B-values of modified TCPs spanned the whole interval from 0 to 1, depending on the fractionation scheme (number of fractions and dose/fraction), showing a maximum (close to 1) at doses/fraction of 8-12 Gy. The B-values calculated using the OER parameter set 1 exhibited a smoother falloff than set 2. An analytical expression was derived to describe the B-value's dependence on the fractionation scheme. The R2-adjusted values varied from 0.63 to 0.67 for LQ models and OER set 1 and from 0.75 to 0.78 for LQ model and OER set 2. Lower values of R2-adjusted were found for LQLM and both OER sets. L and AIC, calculated using a fraction of ηh = 0.15 and the B-value from the authors analytical expression were higher than for other ηh-values, irrespective of model or OER set. Conclusions: The authors model allows to predict the clinical outcome associated with SBRT treatment, taking into account both direct killing and indirect vasculature or stromal damage. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1118/1.4730292 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 4502 Subjects: – SubjectFull: Hypoxemia Type: general – SubjectFull: Lung cancer treatment Type: general – SubjectFull: Health outcome assessment Type: general – SubjectFull: Cancer radiotherapy Type: general – SubjectFull: Stereotaxic techniques Type: general – SubjectFull: Clinical trials Type: general – SubjectFull: Medical publishing Type: general Titles: – TitleFull: A modified hypoxia-based TCP model to investigate the clinical outcome of stereotactic hypofractionated regimes for early stage non-small-cell lung cancer (NSCLC). Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Strigari, L. – PersonEntity: Name: NameFull: Benassi, M. – PersonEntity: Name: NameFull: Sarnelli, A. – PersonEntity: Name: NameFull: Polico, R. – PersonEntity: Name: NameFull: D'Andrea, M. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 07 Text: Jul2012 Type: published Y: 2012 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 39 – Type: issue Value: 7,Part 1 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
