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Nichols R.C.,Proton Therapy
Translational Cancer Research | Year: 2015

Achieving local control for patients with nonmetastatic pancreatic malignancy represents a substantial challenge. For patients with unresectable disease, data from the LAP-07 trial suggests that conventionally delivered X-ray based radiotherapy does not offer a survival improvement compared to treatment with chemotherapy alone. While the study methodology has been challenged, the published results from the ESPAC trial suggest that radiotherapy likewise does not improve survival for patients after extirpative surgery. The shortcomings of X-ray based therapy, to a significant degree, are due to the fact that the tumor targets are intimately surrounded by highly radiosensitive normal tissues resulting in both toxicity and limitation in the deliverable radiotherapy dose. Particle therapy may offer improvements in the therapeutic index as compared to X-ray based therapies. Such improvements may allow for treatment intensification while minimizing normal tissue complications. Herein we review dosimetric studies as well as encouraging preliminary clinical outcome data which suggest that particle therapy may represent a valuable addition to the armamentarium used to treat this malignancy. © 2011 - 2016 Translational Cancer Research. All rights reserved. Source

Ogino T.,Proton Therapy
International Journal of Clinical Oncology | Year: 2012

Proton beam therapy (PBT) makes it possible to deliver a high concentration of radiation to a tumor using its Bragg peak, and it is simple to utilize as its radiobiological characteristics are identical to those of photon beams. PBT has now been used for half a century, and more than 60,000 patients worldwide are reported to have been treated with proton beams. The most significant change to PBT occurred in the 1990s, when the Loma Linda University Medical Center became the first hospital in the world to operate a medically dedicated proton therapy facility. Following its success, similar medically dedicated facilities have been constructed. Internationally, results have demonstrated the therapeutic superiority of PBT over alternative treatment options for several disease sites. Further advances in PBT are expected from both clinical and technological perspectives. © 2011 CARS. Source

Hoppe B.S.,Proton Therapy
Oncology (Williston Park, N.Y.) | Year: 2012

The risk of serious late complications in Hodgkin lymphoma (HL) survivors has led to a variety of strategies for reducing late treatment effects from both chemotherapy and radiation therapy. With radiation therapy, efforts have included reductions in dose, reductions in the size of the target volume, and most recently, significant reductions in the dose to nontargeted normal tissues at risk for radiation damage, achieved by using the emerging technologies of intensity-modulated radiation therapy and proton therapy (PT). PT is associated with a substantial reduction in radiation dose to critical organs, such as the heart and lungs, and has the potential to improve not only the therapeutic ratio, but also both event-free and overall survival. This review addresses the rationale and evidence for--and the challenges, cost implications, and future development of--PT as an important part of the treatment strategy in HL. Source

Jeong H.,Proton Therapy
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2013

We evaluated the dosimetric effect of a respiration motion, and sought an effective planning strategy to compensate the motion using four-dimensional computed tomography (4D CT) dataset of seven selected liver patients. For each patient, we constructed four different proton plans based on: (1) average (AVG) CT, (2) maximum-intensity projection (MIP) CT, (3) AVG CT with density override of tumor volume (OVR), and (4) AVG CT with field-specific proton margin which was determined by the range difference between AVG and MIP plans (mAVG). The overall effectiveness of each planning strategy was evaluated by calculating the cumulative dose distribution over an entire breathing cycle. We observed clear differences between AVG and MIP CT-based plans, with significant underdosages at expiratory and inspiratory phases, respectively. Only the mAVG planning strategy was fully successful as the field-specific proton margin applied in the planning strategy complemented both the limitations of AVG and MIP CT-based strategies. These results demonstrated that respiration motion induced significant changes in dose distribution of 3D proton plans for mobile liver cancer and the changes can be effectively compensated by applying field-specific proton margin to each proton field. Source

McDonald M.W.,Indiana University | McDonald M.W.,Proton Therapy | Linton O.R.,Indiana University | Shah M.V.,Indiana University
International Journal of Radiation Oncology Biology Physics | Year: 2013

Purpose To report the results in patients reirradiated with proton therapy for recurrent or progressive chordoma, with or without salvage surgery. Methods and Materials A retrospective review of 16 consecutive patients treated from 2005 to 2012 was performed. All patients had received at least 1 prior course of radiation therapy to the same area, and all but 1 patient had at least 1 surgical resection for disease before receiving reirradiation. At the time of recurrence or progression, half of the patients underwent additional salvage surgery before receiving reirradiation. The median prior dose of radiation was 75.2 Gy (range, 40-79.2 Gy). Six patients had received prior proton therapy, and the remainder had received photon radiation. The median gross tumor volume at the time of reirradiation was 71 cm3 (range, 0-701 cm3). Reirradiation occurred at a median interval of 37 months after prior radiation (range, 12-129 months), and the median dose of reirradiation was 75.6 Gy (relative biological effectiveness [RBE]) (range. 71.2-79.2 Gy [RBE]), given in standard daily fractionation (n=14) or hyperfractionation (n=2). Results The median follow-up time was 23 months (range, 6-63 months); it was 26 months in patients alive at the last follow-up visit (range, 12-63 months). The 2-year estimate for local control was 85%, overall survival 80%, chordoma-specific survival 88%, and development of distant metastases 20%. Four patients have had local progression: 3 in-field and 1 marginal. Late toxicity included grade 3 bitemporal lobe radionecrosis in 1 patient that improved with hyperbaric oxygen, a grade 4 cerebrospinal fluid leak with meningitis in 1 patient, and a grade 4 ischemic brainstem stroke (out of radiation field) in 1 patient, with subsequent neurologic recovery. Conclusions Full-dose proton reirradiation provided encouraging initial disease control and overall survival for patients with recurrent or progressive chordoma, although additional toxicities may develop with longer follow-up times. © 2013 The Authors. Published by Elsevier Inc. All rights reserved. Source

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