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FDG-PET Semi automatic Segmentation Methods for GTV Delineation in Laryngeal and Hypopharyngeal Cancer
S536
International Journal of Radiation Oncology Biology Physics
2822
Materials/Methods: Before laryngectomy, 21 patients (mean age, 62; range, 49-80 years) with T3 (n Z 3) or T4 (n Z 18) squamous cell carcinoma of the larynx (N Z 12) or hypopharynx (N Z 9) underwent an FDG-PET scan. The GTV was semi-automatically segmented on the PET scans using a Gradient-based (GRAD), a Gaussian-based (GAUSS), the 40% of the maximum signal intensity (SUVmax) and the 50% SUVmax methods. The GTV was manually delineated on the PET scans by a radiation oncologist. After laryngectomy, whole-mount hematoxylin-eosin stained (H&E) sections were obtained. A pathologist delineated the tumor tissue in the H&E sections. Histopathology data was registered to the PET data in three-dimensions using a semi-automatic pathology-imaging registration method. PET segmentations were compared with histopathology. Sensitivity and Positive Predictive Value were calculated as a measure for tumor coverage and tumor overestimation, respectively. Results: Bland-Altman analysis showed small volume differences with pathology for the GRAD, GAUSS and 40% SUVmax segmentations, and larger differences for the manual and 50% SUVmax segmentations. Manual delineations showed larger overestimations for larger tumor volumes, while for the 40% and 50% SUVmax a trend towards larger underestimations for larger tumor volumes was apparent (Table). Tumor volume on pathology was similar to the GRAD and 40% SUVmax segmentations, was overestimated by the GAUSS segmentations and manual delineations and was underestimated by the 50% SUVmax segmentations. Tumor coverage and overestimation by the GRAD, GAUSS and 40% SUVmax segmentations was comparable. Manual delineations showed better coverage but larger overestimation, whereas worse coverage but less overestimation was shown by the 50% SUVmax method. The mismatches between the PET and the tumor localization as derived from histopathology might be partly explained by registration errors, deformations of the specimen and partial volume effects. Conclusions: The GRAD and GAUSS methods are two easy and robust methods to determine a first estimate of the GTV on the PET. However, these segmentations must be adapted on the planning CT scan by a radiation oncologist, to correct for partial volume effects and CT-PET registration errors. Author Disclosure: J. Caldas Magalhaes: None. C.P. Raaijmakers: None. M. Aristophanous: None. J.A. Lee: None. N. Kasperts: None. E.A. Jager: None. N. Kooij: None. C.H. Terhaard: None. M.E. Philippens: None.
Improved GTV Delineation of Laryngeal/Hypopharyngeal Carcinoma on MRI by the Use of Delineation Guidelines E. Jager,1 C.H.J. Terhaard,1 F.A. Pameijer,1 N. Kasperts,1 T. Schakel,1 J. Caldas Magalhaes,1 M.E.P. Philippens,1 N. Kooij,2 and C.P.J. Raaijmakers1; 1University Medical Center Utrecht, Utrecht, Netherlands, 2Laboratory Oost-Nederland, Enschede, Netherlands Purpose/Objective(s): To pathologically validate the accuracy of gross tumor volume (GTV) delineation for laryngeal and hypopharyngeal carcinoma on MRI. Materials/Methods: 21 patients with squamous cell cancer of the larynx (13) or hypopharynx (9), 4 clinical T3 and 18 clinical T4 were included. Prior to total laryngectomy (TLE), 1.5-T-MRI scans (T1w, T2w and T1wGd) were acquired in a radiation therapy mask. After TLE, whole mount H&E-sections were obtained and an experienced head-and-neck pathologist delineated the GTV on the sections. The H&E-sections were then registered to the MR-images. GTV was delineated on the MR-images by three dedicated head-and-neck specialists. First, the GTV was delineated according to clinical practice (MRIdel1). For the second delineation (MRIdel2), high signal intensity on T2w images was considered as peritumoral inflammation, and not included in the GTV. Signal intensity on T1Gd higher than in the tumor bulk was not considered to be tumor. Finally, MRI-GTV (MRIdel3) was delineated in consensus between the 3 observers. Volume calculations and overlap analysis expressed as generalized conformity index (CIgen) were performed. Results: The mean tumor volume was 13.5 ml (SD 11.0) for pathology, 24.9 ml (SD 15.2) for MRIdel1, 19.0 ml (SD 12.9) for MRIdel2 and 18.3 ml (SD 12.9) for MRIdel3. The mean CIgen of MRIdel1, MRIdel2, and MRIdel3 with pathology improved from 0.38 (SD 0.1), to 0.45 (SD 0.1), and to 0.48 (SD 0.1), respectively. Conclusions: Determination of the GTV of laryngeal/ hypopharyngeal cancer is overestimated by MRI. By the using guidelines, the conformity index improved and overestimation of the GTV decreased. Author Disclosure: E. Jager: None. C.H.J. Terhaard: None. F.A. Pameijer: None. N. Kasperts: None. T. Schakel: None. J. Caldas Magalhaes: None. M.E.P. Philippens: None. N. Kooij: None. C.P.J. Raaijmakers: None.
2823
2824
FDG-PET Semi automatic Segmentation Methods for GTV Delineation in Laryngeal and Hypopharyngeal Cancer J. Caldas Magalhaes,1 C.P. Raaijmakers,1 M. Aristophanous,2 J.A. Lee,3 N. Kasperts,1 E.A. Jager,1 N. Kooij,4 C.H. Terhaard,1 and M.E. Philippens1; 1Radiotherapy Department, UMC Utrecht, Utrecht, Netherlands, 2Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Department of Radiation Oncology, Center of Molecular Imaging and Experimental Radiotherapy, Universite´ Catholique de Louvain, Brussels, Belgium, 4Pathology Department, UMC Utrecht, Utrecht, Netherlands
Pretreatment Computed Tomographic Gross Tumor Volume (CTGTV) Is Prognostic for Poor Functional Outcomes in Patients Undergoing Larynx Preservation N.J. Hurst,1 M.M. Dominello,1 L.M. Pereira,2 G. Dyson,2 P. Laszewski,2 N. Robinette,2 H. Lin,2 G.H. Yoo,2 A. Sukari,2 and H. Kim1; 1Wayne State University, Detroit, MI, 2Barbara Ann Karmanos Cancer Institute, Detroit, MI Purpose/Objective(s): The VA Laryngeal Cancer Study and RTOG 91-11 established a role for larynx preservation, utilizing chemoradiation therapy (CRT), as an alternative to total laryngectomy in patients with locally advanced laryngeal cancer. While larynx preservation may afford these patients improvements in laryngectomy-free and disease-free survival, very little has been reported regarding the functional outcomes following
Purpose/Objective(s): To validate four semi-automatic fluorodeoxyglucose (FDG) positron emission tomography (PET) segmentation methods for GTV delineation in laryngeal and hypopharyngeal cancer, in comparison with histopathology and manual FDG-PET delineations.
Scientific Abstract 2823; Table
Tumor Volume Comparison and Overlap Analysis
Volume (mm) Volume comparison using Wilcoxon test Volume Difference using Bland-Altman method(ml) Pearson Correlation Volume Difference vs Pathology Volume Sensitivity (%) Positive Predictive Value (%)
Median (Range) P value BIAS (STD)
Pathology
Manual
GRAD
GAUSS
40% SUVmax
50% SUVmax
8.7 (3.3-40.2) -
13.7 (5.8-61.2) <.0001 7.4 (7.5)
11.3 (5.9-46.0) .12 1.6 (4.3)
13.8 (6.0-46.8) .014 2.2 (3.5)
10.5 (5.2-32.4) .92 -0.11 (5.3)
7.2 (3.3-25.3) .014 -4.0 (5.8)
-0.30 (.18)
-0.15 (.52)
-0.74 (.0001)
-0.88 (<.0001)
71 (11) 60 (16)
74 (9) 61 (16)
R (P value)
-
0.61 (.0034)
Average (STD) Average (STD)
-
82 (9) 53 (15)
68 (12) 63 (18)
53 (14) 71 (16)
International Journal of Radiation Oncology Biology Physics
2822
Materials/Methods: Before laryngectomy, 21 patients (mean age, 62; range, 49-80 years) with T3 (n Z 3) or T4 (n Z 18) squamous cell carcinoma of the larynx (N Z 12) or hypopharynx (N Z 9) underwent an FDG-PET scan. The GTV was semi-automatically segmented on the PET scans using a Gradient-based (GRAD), a Gaussian-based (GAUSS), the 40% of the maximum signal intensity (SUVmax) and the 50% SUVmax methods. The GTV was manually delineated on the PET scans by a radiation oncologist. After laryngectomy, whole-mount hematoxylin-eosin stained (H&E) sections were obtained. A pathologist delineated the tumor tissue in the H&E sections. Histopathology data was registered to the PET data in three-dimensions using a semi-automatic pathology-imaging registration method. PET segmentations were compared with histopathology. Sensitivity and Positive Predictive Value were calculated as a measure for tumor coverage and tumor overestimation, respectively. Results: Bland-Altman analysis showed small volume differences with pathology for the GRAD, GAUSS and 40% SUVmax segmentations, and larger differences for the manual and 50% SUVmax segmentations. Manual delineations showed larger overestimations for larger tumor volumes, while for the 40% and 50% SUVmax a trend towards larger underestimations for larger tumor volumes was apparent (Table). Tumor volume on pathology was similar to the GRAD and 40% SUVmax segmentations, was overestimated by the GAUSS segmentations and manual delineations and was underestimated by the 50% SUVmax segmentations. Tumor coverage and overestimation by the GRAD, GAUSS and 40% SUVmax segmentations was comparable. Manual delineations showed better coverage but larger overestimation, whereas worse coverage but less overestimation was shown by the 50% SUVmax method. The mismatches between the PET and the tumor localization as derived from histopathology might be partly explained by registration errors, deformations of the specimen and partial volume effects. Conclusions: The GRAD and GAUSS methods are two easy and robust methods to determine a first estimate of the GTV on the PET. However, these segmentations must be adapted on the planning CT scan by a radiation oncologist, to correct for partial volume effects and CT-PET registration errors. Author Disclosure: J. Caldas Magalhaes: None. C.P. Raaijmakers: None. M. Aristophanous: None. J.A. Lee: None. N. Kasperts: None. E.A. Jager: None. N. Kooij: None. C.H. Terhaard: None. M.E. Philippens: None.
Improved GTV Delineation of Laryngeal/Hypopharyngeal Carcinoma on MRI by the Use of Delineation Guidelines E. Jager,1 C.H.J. Terhaard,1 F.A. Pameijer,1 N. Kasperts,1 T. Schakel,1 J. Caldas Magalhaes,1 M.E.P. Philippens,1 N. Kooij,2 and C.P.J. Raaijmakers1; 1University Medical Center Utrecht, Utrecht, Netherlands, 2Laboratory Oost-Nederland, Enschede, Netherlands Purpose/Objective(s): To pathologically validate the accuracy of gross tumor volume (GTV) delineation for laryngeal and hypopharyngeal carcinoma on MRI. Materials/Methods: 21 patients with squamous cell cancer of the larynx (13) or hypopharynx (9), 4 clinical T3 and 18 clinical T4 were included. Prior to total laryngectomy (TLE), 1.5-T-MRI scans (T1w, T2w and T1wGd) were acquired in a radiation therapy mask. After TLE, whole mount H&E-sections were obtained and an experienced head-and-neck pathologist delineated the GTV on the sections. The H&E-sections were then registered to the MR-images. GTV was delineated on the MR-images by three dedicated head-and-neck specialists. First, the GTV was delineated according to clinical practice (MRIdel1). For the second delineation (MRIdel2), high signal intensity on T2w images was considered as peritumoral inflammation, and not included in the GTV. Signal intensity on T1Gd higher than in the tumor bulk was not considered to be tumor. Finally, MRI-GTV (MRIdel3) was delineated in consensus between the 3 observers. Volume calculations and overlap analysis expressed as generalized conformity index (CIgen) were performed. Results: The mean tumor volume was 13.5 ml (SD 11.0) for pathology, 24.9 ml (SD 15.2) for MRIdel1, 19.0 ml (SD 12.9) for MRIdel2 and 18.3 ml (SD 12.9) for MRIdel3. The mean CIgen of MRIdel1, MRIdel2, and MRIdel3 with pathology improved from 0.38 (SD 0.1), to 0.45 (SD 0.1), and to 0.48 (SD 0.1), respectively. Conclusions: Determination of the GTV of laryngeal/ hypopharyngeal cancer is overestimated by MRI. By the using guidelines, the conformity index improved and overestimation of the GTV decreased. Author Disclosure: E. Jager: None. C.H.J. Terhaard: None. F.A. Pameijer: None. N. Kasperts: None. T. Schakel: None. J. Caldas Magalhaes: None. M.E.P. Philippens: None. N. Kooij: None. C.P.J. Raaijmakers: None.
2823
2824
FDG-PET Semi automatic Segmentation Methods for GTV Delineation in Laryngeal and Hypopharyngeal Cancer J. Caldas Magalhaes,1 C.P. Raaijmakers,1 M. Aristophanous,2 J.A. Lee,3 N. Kasperts,1 E.A. Jager,1 N. Kooij,4 C.H. Terhaard,1 and M.E. Philippens1; 1Radiotherapy Department, UMC Utrecht, Utrecht, Netherlands, 2Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Department of Radiation Oncology, Center of Molecular Imaging and Experimental Radiotherapy, Universite´ Catholique de Louvain, Brussels, Belgium, 4Pathology Department, UMC Utrecht, Utrecht, Netherlands
Pretreatment Computed Tomographic Gross Tumor Volume (CTGTV) Is Prognostic for Poor Functional Outcomes in Patients Undergoing Larynx Preservation N.J. Hurst,1 M.M. Dominello,1 L.M. Pereira,2 G. Dyson,2 P. Laszewski,2 N. Robinette,2 H. Lin,2 G.H. Yoo,2 A. Sukari,2 and H. Kim1; 1Wayne State University, Detroit, MI, 2Barbara Ann Karmanos Cancer Institute, Detroit, MI Purpose/Objective(s): The VA Laryngeal Cancer Study and RTOG 91-11 established a role for larynx preservation, utilizing chemoradiation therapy (CRT), as an alternative to total laryngectomy in patients with locally advanced laryngeal cancer. While larynx preservation may afford these patients improvements in laryngectomy-free and disease-free survival, very little has been reported regarding the functional outcomes following
Purpose/Objective(s): To validate four semi-automatic fluorodeoxyglucose (FDG) positron emission tomography (PET) segmentation methods for GTV delineation in laryngeal and hypopharyngeal cancer, in comparison with histopathology and manual FDG-PET delineations.
Scientific Abstract 2823; Table
Tumor Volume Comparison and Overlap Analysis
Volume (mm) Volume comparison using Wilcoxon test Volume Difference using Bland-Altman method(ml) Pearson Correlation Volume Difference vs Pathology Volume Sensitivity (%) Positive Predictive Value (%)
Median (Range) P value BIAS (STD)
Pathology
Manual
GRAD
GAUSS
40% SUVmax
50% SUVmax
8.7 (3.3-40.2) -
13.7 (5.8-61.2) <.0001 7.4 (7.5)
11.3 (5.9-46.0) .12 1.6 (4.3)
13.8 (6.0-46.8) .014 2.2 (3.5)
10.5 (5.2-32.4) .92 -0.11 (5.3)
7.2 (3.3-25.3) .014 -4.0 (5.8)
-0.30 (.18)
-0.15 (.52)
-0.74 (.0001)
-0.88 (<.0001)
71 (11) 60 (16)
74 (9) 61 (16)
R (P value)
-
0.61 (.0034)
Average (STD) Average (STD)
-
82 (9) 53 (15)
68 (12) 63 (18)
53 (14) 71 (16)