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Conformity analysis to demonstrate reproducibility of target volumes for Margin-Intense Stereotactic Radiotherapy for borderline-resectable pancreatic cancer.
- Source :
-
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology [Radiother Oncol] 2016 Oct; Vol. 121 (1), pp. 86-91. Date of Electronic Publication: 2016 Aug 09. - Publication Year :
- 2016
-
Abstract
- Background and Purpose: Margin-directed neoadjuvant radiotherapy for borderline-resectable pancreatic cancer (BRPC) aims to facilitate clear surgical margins. A systematic method was developed for definition of a boost target volume prior to a formal phase-I study.<br />Material and Methods: Reference structures were defined by two oncologists and one radiologist, target structures were submitted by eight oncologist investigators and compared using conformity indices. Resultant risk of duodenal bleed (NTCP) was modelled.<br />Results: For GTV, reference volume was 2.1cm <superscript>3</superscript> and investigator mean was 6.03cm <superscript>3</superscript> (95% CI 3.92-8.13cm <superscript>3</superscript> ), for boost volume 1.1cm <superscript>3</superscript> and 1.25cm <superscript>3</superscript> (1.02-1.48cm <superscript>3</superscript> ). Mean Dice conformity coefficient for GTV was 0.47 (0.38-0.56), and for boost volume was significantly higher at 0.61 (0.52-0.70, p=0.01). Discordance index (DI) for GTV was 0.65 (0.56-0.75) and for boost volume was significantly lower at 0.39 (0.28-0.49, p=0.001). NTCP using reference contours was 2.95%, with mean for investigator contour plans 3.93% (3.63-4.22%). Correlations were seen between NTCP and GTV volume (p=0.02) and NTCP and DI (correlation coefficient 0.83 (0.29-0.97), p=0.01).<br />Conclusions: Better conformity with reference was shown for boost volume compared with GTV. Investigator GTV volumes were larger than reference, had higher DI scores and modelled toxicity risk. A consistent method of target structure definition for margin-directed pancreatic radiotherapy is demonstrated.<br /> (Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.)
- Subjects :
- Humans
Neoadjuvant Therapy methods
Pancreatic Neoplasms diagnostic imaging
Pancreatic Neoplasms surgery
Positron-Emission Tomography
Reproducibility of Results
Tomography, X-Ray Computed
Pancreatic Neoplasms radiotherapy
Radiosurgery methods
Radiotherapy Planning, Computer-Assisted methods
Subjects
Details
- Language :
- English
- ISSN :
- 1879-0887
- Volume :
- 121
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
- Publication Type :
- Academic Journal
- Accession number :
- 27519585
- Full Text :
- https://doi.org/10.1016/j.radonc.2016.08.001