scholarly journals RONC-27. PROTON THERAPY REDUCES DOSE TO CRITICAL CENTRAL NERVOUS SYSTEM STRUCTURES IN MEDULLOBLASTOMA: A DOSIMETRIC ANALYSIS OF CHILDREN’S ONCOLOGY GROUP (COG) ACNS0331

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii460-iii460
Author(s):  
Matthew Deek ◽  
Matthew Ladra ◽  
Lan Lin ◽  
Yimei Li ◽  
Yuanyuan Han ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Proton Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Brain Structures ◽  
Published Data ◽  
Imaging Data ◽  
Conformal Radiation Therapy ◽  
Pediatric Medulloblastoma ◽  
Dosimetric Data ◽  
The Impact

Abstract BACKGROUND Recently published data demonstrated proton therapy (PRT) significantly reduced cognitive decline relative to photons for pediatric medulloblastoma. These findings imply that reductions in dose to critical CNS structures during the boost phase may account for better outcomes over time. Here, we examine differences in dosimetric data for medulloblastoma patients treated on ACNS0331 with photon (Intensity Modulated Radiation Therapy, 3D-Conformal Radiation Therapy) vs PRT to identify potential structures responsible for cognitive benefit. METHODS COG ACNS0331 was a randomized trial examining the impact of reduced craniospinal irradiation (CSI) dose (standard vs low dose, in patients aged 3–7) and volume (whole posterior fossa vs involved field) in pediatric medulloblastoma patients. We identified 136 patients (IMRT=95, 3DCRT=28, Proton=13) enrolled on ACNS0331 with complete radiation and imaging data and re-contoured 10 critical brain structures to calculate dose. RESULTS Proton therapy significantly reduced the dose to critical structures. For example, temporal lobe mean dose and V30 were 30Gy/38% (PRT), 40Gy/89% (IMRT), 41Gy/84% (3DCRT)), hippocampi mean dose were 51 Gy (IMRT), 52 Gy (3DCRT), and 44Gy (PRT) and cochlear mean dose were 43 Gy (IMRT), 49 Gy (3DCRT), and 31Gy (PRT). Dose to several other critical structures were also significantly reduced including the whole brain, supratentorium, cerebellum, and pituitary. CONCLUSIONS Proton therapy greatly reduces dose to critical CNS structures when compared to IMRT or 3DCRT. Further studies are needed to correlate dose reductions in these structures with improved cognitive outcomes.

scholarly journals Scattered Dose to Ovary From Radiotherapy for Neuroblastoma in Female Children

2019 ◽  
Vol 18 ◽  
pp. 153303381988798
Author(s):  
Yichen Shen ◽  
Chuanying Zhu ◽  
Mawei Jiang ◽  
Songfang Zhang ◽  
Yongqing Tu ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Ionization Chamber ◽  
Intensity Modulated Radiation Therapy ◽  
Treatment Method ◽  
X Rays ◽  
Conformal Radiation Therapy ◽  
3 Dimensional ◽  
Intensity Modulated ◽  
Dosimetric Data ◽  
Female Children

Purpose: To measure the scattered dose to ovary from radiotherapy for neuroblastoma in female children and to evaluate the relevant risks for radiation-induced ovarian damage. Material and Methods: Radiotherapy for child neuroblastoma was simulated on the water phantom. The scattered dose to ovary is measured by ionization chamber on the linear accelerator with 3-dimensional conformal radiation therapy and intensity-modulated radiation therapy treatment producing 6MV and 10MV X-rays. The treatment planning procedure was carried out on a computer system (TPS, Oncentra). Optimization of the number and orientation of beams were performed in order to minimize the ovarian dose. Results: For the target dose of 21.6 Gy, the scattered dose to ovary was ranged from 1.3 to 46.8 cGy depending on the treatment method and the energy of the beams. The ovarian dose of intensity-modulated radiation therapy is 1.32 to 1.64 times higher than that of 3-dimensional conformal radiation therapy. The ovarian dose of 6MV beam’s energy is 1.52 to 1.64 times higher than that of 10MV beam’s energy. For the radiotherapy, the scattered dose of ovaries on phantom by ionization chamber was 1.40 to 2.32 times higher than that on TPS calculated. Conclusion: The dosimetric data suggest that pediatric radiotherapy is not associated with a risk for permanent damage to the ovaries in female children. Through choosing the beams’ energy and treatment plan’s method, the scattered dose of ovaries can be reduced. The risk for development of hereditary disorders in offspring conceived after exposure is low.

scholarly journals Early Clinical Outcomes of Intensity Modulated Radiation Therapy/Intensity Modulated Proton Therapy Combination in Comparison with Intensity Modulated Radiation Therapy Alone in Oropharynx Cancer Patients

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1549
Author(s):  
Han Gyul Yoon ◽  
Yong Chan Ahn ◽  
Dongryul Oh ◽  
Jae Myoung Noh ◽  
Seung Gyu Park ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Proton Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Combination Group ◽  
Intensity Modulated Proton Therapy ◽  
Oropharynx Cancer ◽  
Intensity Modulated ◽  
Before And After ◽  
Grade 3 ◽  
Early Clinical Outcomes

Purpose: To report the early clinical outcomes of combining intensity-modulated radiation therapy (IMRT) and intensity-modulated proton therapy (IMPT) in comparison with IMRT alone in treating oropharynx cancer (OPC) patients. Materials and Methods: The medical records of 148 OPC patients who underwent definitive radiotherapy (RT) with concurrent systemic therapy, from January 2016 till December 2019 at Samsung Medical Center, were retrospectively reviewed. During the 5.5 weeks’ RT course, the initial 16 (or 18) fractions were delivered by IMRT in all patients, and the subsequent 12 (or 10) fractions were either by IMRT in 81 patients (IMRT only) or by IMPT in 67 (IMRT/IMPT combination), respectively, based on comparison of adaptive re-plan profiles and availability of equipment. Propensity-score matching (PSM) was done on 76 patients (38 from each group) for comparative analyses. Results: With the median follow-up of 24.7 months, there was no significant difference in overall survival and progression free survival between groups, both before and after PSM. Before PSM, the IMRT/IMPT combination group experienced grade ≥ 3 acute toxicities less frequently: mucositis in 37.0% and 13.4% (p < 0.001); and analgesic quantification algorithm (AQA) in 37.0% and 19.4% (p = 0.019), respectively. The same trends were observed after PSM: mucositis in 39.5% and 15.8% (p = 0.021); and AQA in 47.4% and 21.1% (p = 0.016), respectively. In multivariate logistic regression, grade ≥ 3 mucositis was significantly less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.027 and 0.024, respectively). AQA score ≥ 3 was also less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.085 and 0.018, respectively). Conclusions: In treating the OPC patients, with comparable early oncologic outcomes, more favorable acute toxicity profiles were achieved following IMRT/IMPT combination than IMRT alone.

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