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Tuomikoski L, Kapanen M, Collan J, Keyriläinen J, Saarilahti K, Loimu V, Seppälä T, Tenhunen M. Toward a more patient-specific model of post-radiotherapy saliva secretion for head and neck cancer patients. Acta Oncol 2015. [PMID: 26203929 DOI: 10.3109/0284186x.2015.1067717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Reduction of saliva secretion is a common side effect following radiotherapy (RT) for cancer of the head and neck region. The aim of this study is to predict the post-RT salivary function for individual patients prior to treatment and to recognise possible differences in individual radiosensitivity. MATERIAL AND METHODS A predictive model for post-RT salivary function was validated for 64 head and neck cancer patients. The input parameters for the model were salivary excretion fraction (sEF) measured by 99mTc-pertechnetate scintigraphy, total stimulated salivary flow and mean absorbed dose for the major salivary glands. SEF values after RT relative to the baseline before RT (rEF) were compared among the patients using the distance ΔrEF between single gland rEF and the corresponding expected value at the dose response curve. RESULTS A significant correlation (R = 0.86, p = 0.018) was found between the modelled and the measured values of stimulated salivary flow six months after RT. The average prediction error for the saliva flow rate was 6 ml/15 min. A linear relationship between ΔrEF for the left and the right parotid glands was observed both six (R = 0.53) and 12 (R = 0.79) months after RT. The average of absolute values of ΔrEF was 0.20 for parotid glands and 0.22 for submandibular glands. CONCLUSIONS The salivary flow model was validated for 64 patients. The results imply, that one explanation for the discrepancies between the predicted and the measured salivary flow rate values and the common variations found in ΔrEF for the parotid glands may be differences in patients' individual response to radiation. However, quantitative extraction of individual radiosensitivity would require further studies in order to take it into account in predictive models.
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Affiliation(s)
- Laura Tuomikoski
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Mika Kapanen
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
- b Department of Medical Physics , Tampere University Hospital , Tampere , Finland
| | - Juhani Collan
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Jani Keyriläinen
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
- c Department of Oncology and Radiotherapy , Turku University Hospital , Turku , Finland
| | - Kauko Saarilahti
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Venla Loimu
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Tiina Seppälä
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
| | - Mikko Tenhunen
- a HUCH Comprehensive Cancer Center, Department of Radiation Oncology , Helsinki University Central Hospital , Helsinki , Finland
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Vainshtein JM, Moon DH, Feng FY, Chepeha DB, Eisbruch A, Stenmark MH. Long-term quality of life after swallowing and salivary-sparing chemo-intensity modulated radiation therapy in survivors of human papillomavirus-related oropharyngeal cancer. Int J Radiat Oncol Biol Phys 2015; 91:925-33. [PMID: 25832685 DOI: 10.1016/j.ijrobp.2014.12.045] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 12/16/2014] [Accepted: 12/24/2014] [Indexed: 01/30/2023]
Abstract
PURPOSE To evaluate long-term health-related quality of life (HRQOL) in 2 prospective studies of chemo-intensity modulated radiation therapy (chemo-IMRT) for oropharyngeal cancer (OPC). METHODS AND MATERIALS Of 93 patients with stage III/IV OPC treated on prospective studies of swallowing and salivary organ-sparing chemo-IMRT, 69 were eligible for long-term HRQOL assessment. Three validated patient-reported instruments, the Head and Neck QOL (HNQOL) questionnaire, the University of Washington quality of life (UWQOL) questionnaire, and the Xerostomia Questionnaire (XQ), previously administered from baseline through 2 years in the parent studies, were readministered at long-term follow-up, along with the Short-Form 36. Long-term changes in HRQOL from before treatment and 2 years were evaluated. RESULTS Forty patients (58%) with a median follow-up of 6.5 years participated, 39 of whom (97.5%) had confirmed human papillomavirus-positive OPC. Long term, no clinically significant worsening was detected in mean HRQOL scores compared with 2 years, with stable or improved HRQOL from before treatment in nearly all domains. "Moderate" or greater severity problems were uncommon, reported by 5% of patients for eating, 5% for swallowing, and 2.5% and 5% by HNQOL and UWQOL summary scores, respectively. Freedom from percutaneous endoscopic gastrostomy tube dependence and stricture dilation beyond 2 years was 97.5% and 95%, respectively. Eleven percent and 14% of patients reported "moderate" or "severe" long-term worsening in HNQOL Pain and Overall Bother domains, respectively, which were associated with mean dose to the cervical esophagus, larynx, and pharyngeal constrictors. CONCLUSIONS At more than 6 years' median follow-up, OPC patients treated with swallowing and salivary organ-sparing chemo-IMRT reported stable or improved HRQOL in nearly all domains compared with both before treatment and 2-year follow-up. New late toxicity after 2 years was uncommon. Further emphasis on sparing the swallowing organs may yield additional HRQOL gains for long-term OPC survivors.
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Affiliation(s)
| | - Dominic H Moon
- University of Michigan Medical School, Ann Arbor, Michigan
| | - Felix Y Feng
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan
| | - Douglas B Chepeha
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan
| | - Avraham Eisbruch
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
| | - Matthew H Stenmark
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan
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Brouwer CL, Steenbakkers RJ, Langendijk JA, Sijtsema NM. Identifying patients who may benefit from adaptive radiotherapy: Does the literature on anatomic and dosimetric changes in head and neck organs at risk during radiotherapy provide information to help? Radiother Oncol 2015; 115:285-94. [DOI: 10.1016/j.radonc.2015.05.018] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 05/17/2015] [Accepted: 05/24/2015] [Indexed: 10/23/2022]
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Guidi G, Maffei N, Vecchi C, Ciarmatori A, Mistretta GM, Gottardi G, Meduri B, Baldazzi G, Bertoni F, Costi T. A support vector machine tool for adaptive tomotherapy treatments: Prediction of head and neck patients criticalities. Phys Med 2015; 31:442-51. [PMID: 25958225 DOI: 10.1016/j.ejmp.2015.04.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 04/09/2015] [Accepted: 04/15/2015] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Adaptive radiation therapy (ART) is an advanced field of radiation oncology. Image-guided radiation therapy (IGRT) methods can support daily setup and assess anatomical variations during therapy, which could prevent incorrect dose distribution and unexpected toxicities. A re-planning to correct these anatomical variations should be done daily/weekly, but to be applicable to a large number of patients, still require time consumption and resources. Using unsupervised machine learning on retrospective data, we have developed a predictive network, to identify patients that would benefit of a re-planning. METHODS 1200 MVCT of 40 head and neck (H&N) cases were re-contoured, automatically, using deformable hybrid registration and structures mapping. Deformable algorithm and MATLAB(®) homemade machine learning process, developed, allow prediction of criticalities for Tomotherapy treatments. RESULTS Using retrospective analysis of H&N treatments, we have investigated and predicted tumor shrinkage and organ at risk (OAR) deformations. Support vector machine (SVM) and cluster analysis have identified cases or treatment sessions with potential criticalities, based on dose and volume discrepancies between fractions. During 1st weeks of treatment, 84% of patients shown an output comparable to average standard radiation treatment behavior. Starting from the 4th week, significant morpho-dosimetric changes affect 77% of patients, suggesting need for re-planning. The comparison of treatment delivered and ART simulation was carried out with receiver operating characteristic (ROC) curves, showing monotonous increase of ROC area. CONCLUSIONS Warping methods, supported by daily image analysis and predictive tools, can improve personalization and monitoring of each treatment, thereby minimizing anatomic and dosimetric divergences from initial constraints.
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Affiliation(s)
- Gabriele Guidi
- Medical Physics Department, Az. Ospedaliero-Universitaria di Modena, Italy; Physics Department, University of Bologna, Italy.
| | - Nicola Maffei
- Medical Physics Department, Az. Ospedaliero-Universitaria di Modena, Italy; Physics Department, University of Bologna, Italy
| | | | - Alberto Ciarmatori
- Medical Physics Department, Az. Ospedaliero-Universitaria di Modena, Italy; Post-graduate School in Medical Physics, University of Bologna, Italy
| | | | - Giovanni Gottardi
- Medical Physics Department, Az. Ospedaliero-Universitaria di Modena, Italy
| | - Bruno Meduri
- Radiation Oncology Department, Az. Ospedaliero-Universitaria di Modena, Italy
| | | | - Filippo Bertoni
- Radiation Oncology Department, Az. Ospedaliero-Universitaria di Modena, Italy
| | - Tiziana Costi
- Medical Physics Department, Az. Ospedaliero-Universitaria di Modena, Italy
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Ramadaan IS, Peick K, Hamilton DA, Evans J, Iupati D, Nicholson A, Greig L, Louwe RJW. Validation of Varian's SmartAdapt® deformable image registration algorithm for clinical application. Radiat Oncol 2015; 10:73. [PMID: 25889772 PMCID: PMC4465143 DOI: 10.1186/s13014-015-0372-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 03/03/2015] [Indexed: 11/17/2022] Open
Abstract
Background Re-contouring of structures on consecutive planning computed tomography (CT) images for patients that exhibit anatomical changes is elaborate and may negatively impact the turn-around time if this is required for many patients. This study was therefore initiated to validate the accuracy and usefulness of automatic contour propagation for head and neck cancer patients using SmartAdapt® which is the deformable image registration (DIR) application in Varian’s Eclipse™ treatment planning system. Methods CT images of eight head and neck cancer patients with multiple planning CTs were registered using SmartAdapt®. The contoured structures of target volumes and OARs of the primary planning CT were deformed accordingly and subsequently compared with a reference structure set being either: 1) a structure set independently contoured by the treating Radiation Oncologist (RO), or 2) the DIR-generated structure set after being reviewed and modified by the RO. Results Application of DIR offered a considerable time saving for ROs in delineation of structures on CTs that were acquired mid-treatment. Quantitative analysis showed that 84% of the volume of the DIR-generated structures overlapped with the independently re-contoured structures, while 94% of the volume overlapped with the DIR-generated structures after review by the RO. This apparent intra-observer variation was further investigated resulting in the identification of several causes. Qualitative analysis showed that 92% of the DIR-generated structures either need no or only minor modification during RO reviews. Conclusions SmartAdapt is a powerful tool with sufficient accuracy that saves considerable time in re-contouring structures on re-CTs. However, careful review of the DIR-generated structures is mandatory, in particular in areas where tumour regression plays a role.
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Affiliation(s)
- Ihab S Ramadaan
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand. .,Current address: Liz Plummer Cancer Care Centre, Cairns, Australia.
| | - Karsten Peick
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
| | - David A Hamilton
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
| | - Jamie Evans
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
| | - Douglas Iupati
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
| | - Anna Nicholson
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
| | - Lynne Greig
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
| | - Robert J W Louwe
- Department of Radiation Oncology, Wellington Blood and Cancer Centre, Wellington Hospital, Private Bag 7902, 6242, Wellington, New Zealand.
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Roussakis YG, Dehghani H, Green S, Webster GJ. Validation of a dose warping algorithm using clinically realistic scenarios. Br J Radiol 2015; 88:20140691. [PMID: 25791569 PMCID: PMC4628476 DOI: 10.1259/bjr.20140691] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Objective: Dose warping following deformable image registration (DIR) has been proposed for interfractional dose accumulation. Robust evaluation workflows are vital to clinically implement such procedures. This study demonstrates such a workflow and quantifies the accuracy of a commercial DIR algorithm for this purpose under clinically realistic scenarios. Methods: 12 head and neck (H&N) patient data sets were used for this retrospective study. For each case, four clinically relevant anatomical changes have been manually generated. Dose distributions were then calculated on each artificially deformed image and warped back to the original anatomy following DIR by a commercial algorithm. Spatial registration was evaluated by quantitative comparison of the original and warped structure sets, using conformity index and mean distance to conformity (MDC) metrics. Dosimetric evaluation was performed by quantitative comparison of the dose–volume histograms generated for the calculated and warped dose distributions, which should be identical for the ideal “perfect” registration of mass-conserving deformations. Results: Spatial registration of the artificially deformed image back to the planning CT was accurate (MDC range of 1–2 voxels or 1.2–2.4 mm). Dosimetric discrepancies introduced by the DIR were low (0.02 ± 0.03 Gy per fraction in clinically relevant dose metrics) with no statistically significant difference found (Wilcoxon test, 0.6 ≥ p ≥ 0.2). Conclusion: The reliability of CT-to-CT DIR-based dose warping and image registration was demonstrated for a commercial algorithm with H&N patient data. Advances in knowledge: This study demonstrates a workflow for validation of dose warping following DIR that could assist physicists and physicians in quantifying the uncertainties associated with dose accumulation in clinical scenarios.
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Affiliation(s)
- Y G Roussakis
- 1 School of Computer Sciences, University of Birmingham, Edgbaston, Birmingham, UK
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Sanguineti G, Ricchetti F, Wu B, McNutt T, Fiorino C. Parotid gland shrinkage during IMRT predicts the time to Xerostomia resolution. Radiat Oncol 2015; 10:19. [PMID: 25595326 PMCID: PMC4307228 DOI: 10.1186/s13014-015-0331-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/11/2015] [Indexed: 12/04/2022] Open
Abstract
Purpose To assess the impact of mid-treatment parotid gland shrinkage on long term xerostomia during IMRT for oropharyngeal SCC. Methods and materials All patients treated with IMRT at a single Institution from November 2007 to June 2010 and undergoing weekly CT scans were selected. Parotid glands were contoured retrospectively on the mid treatment CT scan. For each parotid gland, the percent change relative to the planning volume was calculated and combined as weighted average. Patients were considered to be xerostomic if developed GR2+ dry mouth according to CTCAE v3.0. Predictors of the time to xerostomia resolution or downgrade to 1 were investigated at both uni- and multivariate analysis. Results 85 patients were selected. With a median follow up of 35.8 months (range: 2.4-62.6 months), the actuarial rate of xerostomia is 26.2% (SD: 5.3%) and 15.9% (SD: 5.3%) at 2 and 3 yrs, respectively. At multivariate analysis, mid-treatment shrink along with weighted average mean parotid dose at planning and body mass index are independent predictors of the time to xerostomia resolution. Patients were pooled in 4 groups based on median values of both mid-treatment shrink (cut-off: 19.6%) and mean WA parotid pl-D (cut-off: 35.7 Gy). Patients with a higher than median parotid dose at planning and who showed poor shrinkage at mid treatment are the ones with the outcome significantly worse (3-yr rate of xerostomia ≈ 50%) than the other three subgroups (3-yr rate of xerostomia ≈ 10%). Conclusion For a given planned dose, patients whose parotids significantly shrink during IMRT are less likely to be long-term supplemental fluids dependent.
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Affiliation(s)
- Giuseppe Sanguineti
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA.
| | - Francesco Ricchetti
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA.
| | - Binbin Wu
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA.
| | - Todd McNutt
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA.
| | - Claudio Fiorino
- Department of Medical Physics, Ospedale San Raffaele, Milan, Italy.
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Popovic KS, Harej M, Furlan T, Popovič P, Strojan P. Role of perfusion computed tomography in assessing submandibular gland radiochemotherapy-induced injury. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 118:241-7. [PMID: 25047931 DOI: 10.1016/j.oooo.2014.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/20/2014] [Accepted: 04/29/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE We aimed to detect changes in the volume and perfusion parameters of the submandibular glands during and after radiochemotherapy. STUDY DESIGN Twelve patients underwent computed tomography (CT) and perfusion CT before radiochemotherapy, after 40 Gy, after 70 Gy, and 3 months after radiochemotherapy. Submandibular gland volume, blood volume, permeability surface area product, and blood flow were quantified. RESULTS Submandibular gland volumes during and after therapy were significantly lower compared with the baseline value (P < .001). Blood volume, blood flow, and permeability surface area product values showed statistically significant reduction during and 3 months after therapy. A significant linear correlation was found between changes in submandibular gland volume and of the perfusion parameter blood volume in the period between baseline and 3 months after therapy (P = .012; RP = -0.697). CONCLUSIONS Changes in submandibular gland volume and dynamics of perfusion parameters imply that radiation-induced injury of submandibular glands develops early during radiochemotherapy.
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Affiliation(s)
| | - Maja Harej
- Institute of Radiology, University Medical Center Ljubljana, Ljubljana, Slovenia
| | - Tjaša Furlan
- Institute of Radiology, University Medical Center Ljubljana, Ljubljana, Slovenia
| | - Peter Popovič
- Institute of Radiology, University Medical Center Ljubljana, Ljubljana, Slovenia
| | - Primož Strojan
- Division of Radiation Oncology, Oncology Institute Ljubljana, Ljubljana, Slovenia
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Vainshtein JM, Griffith KA, Feng FY, Vineberg KA, Chepeha DB, Eisbruch A. Patient-reported voice and speech outcomes after whole-neck intensity modulated radiation therapy and chemotherapy for oropharyngeal cancer: prospective longitudinal study. Int J Radiat Oncol Biol Phys 2014; 89:973-980. [PMID: 24803039 DOI: 10.1016/j.ijrobp.2014.03.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 01/09/2014] [Accepted: 03/07/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE To describe voice and speech quality changes and their predictors in patients with locally advanced oropharyngeal cancer treated on prospective clinical studies of organ-preserving chemotherapy-intensity modulated radiation therapy (chemo-IMRT). METHODS AND MATERIALS Ninety-one patients with stage III/IV oropharyngeal cancer were treated on 2 consecutive prospective studies of definitive chemoradiation using whole-field IMRT from 2003 to 2011. Patient-reported voice and speech quality were longitudinally assessed from before treatment through 24 months using the Communication Domain of the Head and Neck Quality of Life (HNQOL-C) instrument and the Speech question of the University of Washington Quality of Life (UWQOL-S) instrument, respectively. Factors associated with patient-reported voice quality worsening from baseline and speech impairment were assessed. RESULTS Voice quality decreased maximally at 1 month, with 68% and 41% of patients reporting worse HNQOL-C and UWQOL-S scores compared with before treatment, and improved thereafter, recovering to baseline by 12-18 months on average. In contrast, observer-rated larynx toxicity was rare (7% at 3 months; 5% at 6 months). Among patients with mean glottic larynx (GL) dose ≤20 Gy, >20-30 Gy, >30-40 Gy, >40-50 Gy, and >50 Gy, 10%, 32%, 25%, 30%, and 63%, respectively, reported worse voice quality at 12 months compared with before treatment (P=.011). Results for speech impairment were similar. Glottic larynx dose, N stage, neck dissection, oral cavity dose, and time since chemo-IMRT were univariately associated with either voice worsening or speech impairment. On multivariate analysis, mean GL dose remained independently predictive for both voice quality worsening (8.1%/Gy) and speech impairment (4.3%/Gy). CONCLUSIONS Voice quality worsening and speech impairment after chemo-IMRT for locally advanced oropharyngeal cancer were frequently reported by patients, underrecognized by clinicians, and independently associated with GL dose. These findings support reducing mean GL dose to as low as reasonably achievable, aiming at ≤20 Gy when the larynx is not a target.
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Affiliation(s)
| | - Kent A Griffith
- Center for Cancer Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Felix Y Feng
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan
| | - Karen A Vineberg
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan
| | - Douglas B Chepeha
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan
| | - Avraham Eisbruch
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
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Balter J, Eisbruch A. In Reply to Ren et al. Int J Radiat Oncol Biol Phys 2014; 88:1214. [DOI: 10.1016/j.ijrobp.2014.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 01/18/2014] [Indexed: 11/24/2022]
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Ren G, Ma L, Xu S. In Regard to Hunter et al. Int J Radiat Oncol Biol Phys 2014; 88:1213-4. [DOI: 10.1016/j.ijrobp.2014.01.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Accepted: 01/18/2014] [Indexed: 10/25/2022]
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