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Novel Concepts In Dysphagia, Larynx And Pharyngeal Constrictors Tolerance
Proceedings of the 53rd Annual ASTRO Meeting
2640
S517
Novel Concepts In Dysphagia, Larynx And Pharyngeal Constrictors Tolerance
W. F. Mourad1,2, K. Hu1, D. Shasha1, W. Choi1, S. Rauth1, E. Katsoulakis3, R. Woode1, L. Harrison1 1
Beth Israel Medical Center, New York, NY, 2Albert Einstein College of Medicine, New York, NY, 3SUNY Downstate Medical Center, New York, NY Purpose/Objective(s): Dosage exceeding tolerance of the constrictor muscles and larynx are thought to be a major etiology for long-term dysphagia. To explore dose and functional outcomes we explored the impact of definitive single modality radiation therapy (RT) in the management of early glottic cancer on the long term swallowing outcomes. Materials/Methods: This is a single-institution, retrospective study investigating the long term impact of RT to T1-T2 glottic cancer on dysphagia. From January (1997 - 2010), 253 patients, all had T1-T2 glottic cancer underwent RT. RT was delivered by 2D (clinical sim) and by 3D (CT sim). All patients underwent RT with Co60 or LINAC 6MV photon. Parallel opposed wedge paired fields were used and daily 5 mm bolus was applied in all patients treated with 6 MV photon to avoid under-dose of the anterior laryngeal structures. The whole larynx, middle and inferior pharyngeal constrictors (PCs), were contoured and dose volume histograms (DVH) were generated to assess the dose delivered. All patients were treated in the same fashion regardless of the RT techniques used. Results: A total of 253 patients treated with laryngeal sparing definitive RT. 202 pts-80% underwent 2D clinical sim while 51 pts-20% treated with 3D after CT sim for whom DVHs are available for larynx and PCs. The median age for the whole cohort is 65, white 80%, Males 87%. T1 - 77% and T2 - 23%. The median dose delivered to the larynx 63Gy (60 - 72Gy), median fraction size 225 cGy (180 - 225cGy), median duration of RT 41 days, median follow up of the whole cohort is 6.8 years. For the 51 patients who underwent CT sim followed by definitive 3D-RT. The median mean dose delivered to the whole Lx was 5710 cGy to median volume of 34 cm3. The Lx V50,60,65 were 83,77,65 respectively. The median mean dose to the PC within and nearby the RT fields was 5368 cGy delivered to median volume of 15 cm3. The PC V50,60,65 were 81,70,55 respectively. For all (253) patients acute dysphagia grade (0, 1) 81%, grade 2 was 19%. Chronic dysphagia and long term impaired swallowing is 0. Conclusions: Definitive single modality RT, up-to 6750 cGy at 225 cGy/fx, to the Lx and (middle and inferior) PCs is not a predictor for long-term swallowing impairment. The tolerance of these structures should be revisited in further studies. The separate delineation of these structures may better identify dose tolerances to maintain swallowing function and further prioritize structures’ importance in causing RT induced long term dysphagia.
Median
PC
LX
Volume /cm3 Mean Dose /cGy Maximum Dose /cGy V40 V50 V60 V65
15 5368 6720 83 81 70 55
34 5710 6744 86 83 77 65
Author Disclosure: W.F. Mourad: None. K. Hu: None. D. Shasha: None. W. Choi: None. S. Rauth: None. E. Katsoulakis: None. R. Woode: None. L. Harrison: None.
2641
Value Of CT-MRI Fusion On Target Volume Delineation For Hypopharyngeal Cancer
R. Yoshimura1, R. Notake1, K. Sasamori1, Y. Kyuma1, S. Ohtani1, K. Hayashi1, K. Nakagawa1, H. Shibuya1, T. Kobayashi2, J. Itami2 1
Tokyo Medical and Dental University, Tokyo, Japan, 2National Cancer Center, Tokyo, Japan
Purpose/Objective(s): To analyze the spatial and volumetric accuracy of magnetic resonance imaging (MRI) radiotherapy planning (RTP) scans of the head and neck using an immobilization device and the fusion of these scans with RTP-computed tomography (CT) scans, and to evaluate the validity of CT-MRI fusion in the delineation of the gross tumor volume (GTV) for hypopharyngeal cancer (HPC). Materials/Methods: Thirteen patients with stage II - IV HPC were scanned using plain CT and T2-weighted MRI for GTV boost planning during a series of radiotherapy treatments. The MRI scan was performed using a body coil on a flat board, and the immobilization shell was covered by a hand-made coil holder. The CT and MRI results were fused using Xio, v4.40. The accuracy of the CT-MRI fusion was assessed by calculating the volume overlap index (VOI) between the CT and MRI images of each structure. The GTV on the CT-MRI fusion images was delineated as a result of the modification of the GTV on the MRI scans adjusted to the CT scans. The GTV values for the primary tumor (GTVp) and lymph node metastasis (GTVn) on the CT-MRI fusion images were compared to those obtained using CT alone and the VOI was calculated as follows: VOI = (Area of intersection between CT and MRI or CT-MRI fusion)/([CT + MRI or CT-MRI fusion volume]/2). Results: The volumes of the spinal cord, brain stem, and mandibular bone on the MRI results were significantly smaller than those on the CT results, but the volumes of the parotid gland, submandibular gland, oral cavity or thyroid gland were not statistically different. The mean (range) of the VOI between the CT and MRI results for the spinal cord, brain stem, parotid gland, submandibular gland, mandibular bone, oral cavity, and thyroid gland were 0.72 (0.56 - 0.87), 0.75 (0.58 - 0.89), 0.80 (0.56 - 0.90), 0.69 (0.29 - 0.80), 0.71 (0.45 - 0.89), 0.87 (0.75 - 0.92), and 0.70 (0.55 - 0.83), respectively. The mean GTVp on the CT and CT-MRI fusion images were 10.3 cm3 and 8.4 cm3 (p = 0.57), respectively, and the mean (range) of the VOI was 0.57 (0.13 - 0.81). The
2640
S517
Novel Concepts In Dysphagia, Larynx And Pharyngeal Constrictors Tolerance
W. F. Mourad1,2, K. Hu1, D. Shasha1, W. Choi1, S. Rauth1, E. Katsoulakis3, R. Woode1, L. Harrison1 1
Beth Israel Medical Center, New York, NY, 2Albert Einstein College of Medicine, New York, NY, 3SUNY Downstate Medical Center, New York, NY Purpose/Objective(s): Dosage exceeding tolerance of the constrictor muscles and larynx are thought to be a major etiology for long-term dysphagia. To explore dose and functional outcomes we explored the impact of definitive single modality radiation therapy (RT) in the management of early glottic cancer on the long term swallowing outcomes. Materials/Methods: This is a single-institution, retrospective study investigating the long term impact of RT to T1-T2 glottic cancer on dysphagia. From January (1997 - 2010), 253 patients, all had T1-T2 glottic cancer underwent RT. RT was delivered by 2D (clinical sim) and by 3D (CT sim). All patients underwent RT with Co60 or LINAC 6MV photon. Parallel opposed wedge paired fields were used and daily 5 mm bolus was applied in all patients treated with 6 MV photon to avoid under-dose of the anterior laryngeal structures. The whole larynx, middle and inferior pharyngeal constrictors (PCs), were contoured and dose volume histograms (DVH) were generated to assess the dose delivered. All patients were treated in the same fashion regardless of the RT techniques used. Results: A total of 253 patients treated with laryngeal sparing definitive RT. 202 pts-80% underwent 2D clinical sim while 51 pts-20% treated with 3D after CT sim for whom DVHs are available for larynx and PCs. The median age for the whole cohort is 65, white 80%, Males 87%. T1 - 77% and T2 - 23%. The median dose delivered to the larynx 63Gy (60 - 72Gy), median fraction size 225 cGy (180 - 225cGy), median duration of RT 41 days, median follow up of the whole cohort is 6.8 years. For the 51 patients who underwent CT sim followed by definitive 3D-RT. The median mean dose delivered to the whole Lx was 5710 cGy to median volume of 34 cm3. The Lx V50,60,65 were 83,77,65 respectively. The median mean dose to the PC within and nearby the RT fields was 5368 cGy delivered to median volume of 15 cm3. The PC V50,60,65 were 81,70,55 respectively. For all (253) patients acute dysphagia grade (0, 1) 81%, grade 2 was 19%. Chronic dysphagia and long term impaired swallowing is 0. Conclusions: Definitive single modality RT, up-to 6750 cGy at 225 cGy/fx, to the Lx and (middle and inferior) PCs is not a predictor for long-term swallowing impairment. The tolerance of these structures should be revisited in further studies. The separate delineation of these structures may better identify dose tolerances to maintain swallowing function and further prioritize structures’ importance in causing RT induced long term dysphagia.
Median
PC
LX
Volume /cm3 Mean Dose /cGy Maximum Dose /cGy V40 V50 V60 V65
15 5368 6720 83 81 70 55
34 5710 6744 86 83 77 65
Author Disclosure: W.F. Mourad: None. K. Hu: None. D. Shasha: None. W. Choi: None. S. Rauth: None. E. Katsoulakis: None. R. Woode: None. L. Harrison: None.
2641
Value Of CT-MRI Fusion On Target Volume Delineation For Hypopharyngeal Cancer
R. Yoshimura1, R. Notake1, K. Sasamori1, Y. Kyuma1, S. Ohtani1, K. Hayashi1, K. Nakagawa1, H. Shibuya1, T. Kobayashi2, J. Itami2 1
Tokyo Medical and Dental University, Tokyo, Japan, 2National Cancer Center, Tokyo, Japan
Purpose/Objective(s): To analyze the spatial and volumetric accuracy of magnetic resonance imaging (MRI) radiotherapy planning (RTP) scans of the head and neck using an immobilization device and the fusion of these scans with RTP-computed tomography (CT) scans, and to evaluate the validity of CT-MRI fusion in the delineation of the gross tumor volume (GTV) for hypopharyngeal cancer (HPC). Materials/Methods: Thirteen patients with stage II - IV HPC were scanned using plain CT and T2-weighted MRI for GTV boost planning during a series of radiotherapy treatments. The MRI scan was performed using a body coil on a flat board, and the immobilization shell was covered by a hand-made coil holder. The CT and MRI results were fused using Xio, v4.40. The accuracy of the CT-MRI fusion was assessed by calculating the volume overlap index (VOI) between the CT and MRI images of each structure. The GTV on the CT-MRI fusion images was delineated as a result of the modification of the GTV on the MRI scans adjusted to the CT scans. The GTV values for the primary tumor (GTVp) and lymph node metastasis (GTVn) on the CT-MRI fusion images were compared to those obtained using CT alone and the VOI was calculated as follows: VOI = (Area of intersection between CT and MRI or CT-MRI fusion)/([CT + MRI or CT-MRI fusion volume]/2). Results: The volumes of the spinal cord, brain stem, and mandibular bone on the MRI results were significantly smaller than those on the CT results, but the volumes of the parotid gland, submandibular gland, oral cavity or thyroid gland were not statistically different. The mean (range) of the VOI between the CT and MRI results for the spinal cord, brain stem, parotid gland, submandibular gland, mandibular bone, oral cavity, and thyroid gland were 0.72 (0.56 - 0.87), 0.75 (0.58 - 0.89), 0.80 (0.56 - 0.90), 0.69 (0.29 - 0.80), 0.71 (0.45 - 0.89), 0.87 (0.75 - 0.92), and 0.70 (0.55 - 0.83), respectively. The mean GTVp on the CT and CT-MRI fusion images were 10.3 cm3 and 8.4 cm3 (p = 0.57), respectively, and the mean (range) of the VOI was 0.57 (0.13 - 0.81). The