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Browsing by Author "McDonald, Mark W."
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Item Ability of the National Surgical Quality Improvement Program Risk Calculator to Predict Complications Following Total Laryngectomy(JAMA, 2016-10) Schneider, Alexander L.; Deig, Christopher R.; Prasad, Kumar G.; Nelson, Benton G.; Mantravadi, Avinash V.; Brigance, Joseph S.; Langer, Mark P.; McDonald, Mark W.; Johnstone, Peter A.; Moore, Michael G.; Department of Otololaryngology-Head and Neck Surgery, School of MedicineImportance The accuracy of the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) risk calculator has been assessed in multiple surgical subspecialties; however, there have been no publications doing the same in the head and neck surgery literature. Objective To evaluate the accuracy of the calculator’s predictions in a single institution’s total laryngectomy (TL) population. Design, Setting, and Participants Total laryngectomies performed between 2013 and 2014 at a tertiary referral academic center were evaluated using the risk calculator. Predicted 30-day outcomes were compared with observed outcomes for return to operating room, surgical site infection, postoperative pneumonia, length of stay, and venous thromboembolism. Main Outcomes and Measures Comparison of the NSQIP risk calculator’s predicted postoperative complication rates and length of stay to what occurred in this patient cohort using percent error, Brier scores, area under the receiver operating characteristic curve, and Pearson correlation analysis. Results Of 49 patients undergoing TL, the mean (SD) age at operation was 59 (9.3) years, with 67% male. The risk calculator had limited efficacy predicting perioperative complications in this group of patients undergoing TL with or without free tissue reconstruction or preoperative chemoradiation or radiation therapy with a few exceptions. The calculator overestimated the occurrence of pneumonia by 165%, but underestimated surgical site infection by 7%, return to operating room by 24%, and length of stay by 13%. The calculator had good sensitivity and specificity of predicting surgical site infection for patients undergoing TL with free flap reconstruction (area under the curve, 0.83). For all other subgroups, however, the calculator had poor sensitivity and specificity for predicting complications. Conclusions and Relevance The risk calculator has limited utility for predicting perioperative complications in patients undergoing TL. This is likely due to the complexity of the treatment of patients with head and neck cancer and factors not taken into account when calculating a patient’s risk.Item Acute toxicity in comprehensive head and neck radiation for nasopharynx and paranasal sinus cancers: cohort comparison of 3D conformal proton therapy and intensity modulated radiation therapy.(BMC, 2016) McDonald, Mark W.; Liu, Yuan; Moore, Michael G.; Johnstone, Peter A. S.; Department of Otolaryngology--Head & Neck Surgery, IU School of MedicineBackground: To evaluate acute toxicity endpoints in a cohort of patients receiving head and neck radiation with proton therapy or intensity modulated radiation therapy (IMRT). Methods: Forty patients received comprehensive head and neck radiation including bilateral cervical nodal radiation, given with or without chemotherapy, for tumors of the nasopharynx, nasal cavity or paranasal sinuses, any T stage, N0-2. Fourteen received comprehensive treatment with proton therapy, and 26 were treated with IMRT, either comprehensively or matched to proton therapy delivered to the primary tumor site. Toxicity endpoints assessed included g-tube dependence at the completion of radiation and at 3 months after radiation, opioid pain medication requirement compared to pretreatment normalized as equivalent morphine dose (EMD) at completion of treatment, and at 1 and 3 months after radiation. Results: In a multivariable model including confounding variables of concurrent chemotherapy and involved nodal disease, comprehensive head and neck radiation therapy using proton therapy was associated with a lower opioid pain requirement at the completion of radiation and a lower rate of gastrostomy tube dependence by the completion of radiation therapy and at 3 months after radiation compared to IMRT. Proton therapy was associated with statistically significant lower mean doses to the oral cavity, esophagus, larynx, and parotid glands. In subgroup analysis of 32 patients receiving concurrent chemotherapy, there was a statistically significant correlation with a greater opioid pain medication requirement at the completion of radiation and both increasing mean dose to the oral cavity and to the esophagus. Conclusions: Proton therapy was associated with significantly reduced radiation dose to assessed non-target normal tissues and a reduced rate of gastrostomy tube dependence and opioid pain medication requirements. This warrants further evaluation in larger studies, ideally with patient-reported toxicity outcomes and quality of life endpoints.Item Dose perturbation effect of metallic spinal implants in proton beam therapy(2015) Jia, Yingcui; Zhao, Li; Cheng, Chee-Wei; McDonald, Mark W.; Das, Indra J.; Department of Radiation Oncology, IU School of MedicineThe purpose of this study was to investigate the effect of dose perturbations for two metallic spinal screw implants in proton beam therapy in the perpendicular and parallel beam geometry. A 5.5 mm (diameter) by 45 mm (length) stainless steel (SS) screw and a 5.5 mm by 35 mm titanium (Ti) screw commonly used for spinal fixation were CT-scanned in a hybrid phantom of water and solid water. The CT data were processed with an orthopedic metal artifact reduction (O-MAR) algorithm. Treatment plans were generated for each metal screw with a proton beam oriented, first parallel and then perpendicular, to the longitudinal axis of the screw. The calculated dose profiles were compared with measured results from a plane-parallel ion chamber and Gafchromic EBT2 films. For the perpendicular setup, the measured dose immediately downstream from the screw exhibited dose enhancement up to 12% for SS and 8% for Ti, respectively, but such dose perturbation was not observed outside the lateral edges of the screws. The TPS showed 5% and 2% dose reductions immediately at the interface for the SS nd Ti screws, respectively, and up to 9% dose enhancements within 1 cm outside of the lateral edges of the screws. The measured dose enhancement was only observed within 5 mm from the interface along the beam path. At deeper depths, the lateral dose profiles appeared to be similar between the measurement and TPS, with dose reduction in the screw shadow region and dose enhancement within 1–2 cm outside of the lateral edges of the metals. For the parallel setup, no significant dose perturbation was detected at lateral distance beyond 3 mm away from both screws. Significant dose discrepancies exist between TPS calculations and ion chamber and film measurements in close proximity of high-Z inhomogeneities. The observed dose enhancement effect with proton therapy is not correctly modeled by TPS. An extra measure of caution should be taken when evaluating dosimetry with spinal metallic implants.Item Proton therapy for atypical meningiomas(Springer, 2015-05) McDonald, Mark W.; Plankenhorn, David A.; McMullen, Kevin P.; Henderson, Mark A.; Dropcho, Edward J.; Shah, Mitesh V.; Cohen-Gadol, Aaron A.; Department of Radiation Oncology, IU School of MedicineWe report clinical outcomes of proton therapy in patients with World Health Organization grade 2 (atypical) meningiomas. Between 2005 and 2013, 22 patients with atypical meningiomas were treated to a median dose of 63 Gy (RBE) using proton therapy, as an adjuvant therapy after surgery (n = 12) or for recurrence or progression of residual tumor (n = 10). Six patients had presumed radiation-induced meningiomas, but none had received prior radiotherapy for their meningioma. The median follow-up time after radiation was 39 months (range 7–104) and all patients remain alive at last follow-up. The 5-year estimate of local control was 71.1 % (95 % CI 49.3–92.9 %). The 5-year estimate of local control was 87.5 % following a radiation dose >60 Gy (RBE), compared to 50.0 % for ≤60 Gy (RBE) (p = 0.038). The 5-year estimate of neuraxis dissemination was 5 % (95 % CI 0–14.6 %) and 6.2 % (95 % CI 0–18.2 %) for metastases outside of the central nervous system. Radiation necrosis was observed in one patient with a history of prior cranial irradiation. Fractionated proton therapy was associated with favorable tumor control rates for grade 2 meningiomas. Prospective studies are needed to define the optimal radiation dose for high-grade meningiomas.Item Proton Therapy for Head and Neck Adenoid Cystic Carcinoma: Initial Clinical Outcomes(Wiley, 2015-01) Linton, Okechukwu R.; Moore, Michael G.; Brigance, Joseph S.; Summerlin, Don-John; McDonald, Mark W.; Department of Otolaryngology Head & Neck Surgery, IU School of MedicineBackground The purpose of this study was to report outcomes of proton therapy in head and neck adenoid cystic carcinoma. Methods We conducted a retrospective analysis of 26 patients treated between 2004 and 2012. Twenty patients (77%) had base of skull involvement; 19 (73%) were treated for initial disease and 7 (27%) for recurrent disease. Twenty patients were treated postoperatively, 6 after biopsy alone and 24 had positive margins or gross residual disease. Median dose delivered was 72 Gy (relative biological effectiveness [RBE]). Results Median follow-up was 25 months (range, 7–50 months). The 2-year overall survival was 93% for initial disease course and 57% for recurrent disease (p = .19). The 2-year local control was 95% for initial disease and 86% for recurrent disease (p = .48). The 2-year distant metastatic rate was 25%. Late toxicity of grade 0 or 1 was seen in 17 patients, grade 2 in 5, grade 3 in 2, grade 4 in 1, and grade 5 in 1. Conclusion Initial outcomes of proton therapy are encouraging. Longer follow-up is required.Item Quantifying Proton Fields for Midline Brain Tumors: A Benefit/Cost Analysis of Planning Objectives(The Particle Therapy Cooperative Group, 2016) Estabrook, Neil C.; Hoene, Ted A.; Carlin, Paul S.; McDonald, Mark W.; Radiation Oncology, School of MedicinePurpose: We sought to quantify the optimum number of beams by using a midline sagittal arrangement for midline brain tumors when considering the competing demands of a high degree of target conformation and maximizing reduction of nontarget brain dose. The volume of nontarget brain tissue receiving between 5 and 20 Gy (V5-V20) was selected to measure "low-dose bath" to normal brain. Materials and Methods: An exploratory model was developed with 6 midline brain targets created by using spheres of 1-, 3-, and 5-cm diameters located in superficial and deep locations. For each, five 3-dimensional proton treatment plans with uniform beam scanning were generated by using 1 to 5 fields. Dose-volume histograms were analyzed to calculate conformation number and V5-V20. A benefit/cost analysis was performed to determine the marginal gain in conformation number and the marginal cost of V5-V20 for the addition of each field and hypothesize the optimum number of treatment fields. We tested our hypothesis by re-planning 10 actual patient tumors with the same technique to compare the averages of these 50 plans to our model. Results: Our model and validation cohort demonstrated the largest marginal benefit in target conformation and the lowest marginal cost in normal brain V5-V20 with the addition of a second proton field. The addition of a third field resulted in a relative marginal benefit in target conformation of just 3.9% but a relative marginal cost in V5-V20 of 78.7%. Normal brain absolute V5-V20 increased in a nearly linear fashion with each additional field. Conclusions: When treating midline brain lesions with 3-dimensional proton therapy in an array of midline sagittal beams, our model suggests the most appropriate number of fields is 2. There was little marginal benefit in target conformation and increasing cost of normal brain dose when increasing the number of fields beyond this.