Treatment planning with protons for pediatric retinoblastoma, medulloblastoma, and pelvic sarcoma: How do protons compare with other conformal techniques?

Lee, Catherine T.; Bilton, Stephen; Famiglietti, Robin; Riley, B.; Mahajan, Anita; Chang, Eric L.; Maor, Moshe; Woo, Shiao Y.; Cox, James D.; Smith, Alfred R.

doi:10.1016/j.ijrobp.2005.01.060

Cited by 223 publications

(151 citation statements)

References 20 publications

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“…IMRT, however, exposed 50% of the volumes of lung and kidney to significantly higher doses than with conventional photon irradiation. Similar findings have been recently described by Lee et al 10 Yuh et al 11 from Loma Linda University reported on the outcome of exclusive proton irradiation in young children with medulloblastoma. Treatment consisted of 36 CGE to the craniospinal axis followed by an 18 CGE boost to the posterior fossa.…”

Section: Central Nervous System Tumorssupporting

confidence: 89%

“…In patients with hereditary retinoblastoma, this risk has been reported to be as high as 51% at 50 years. 12 Lee et al, 10 in a comparative planning study, demonstrated that proton therapy provides superior target coverage with optimal sparing of orbital bone compared with 3D-CRT and IMRT. Retrospective research has indicated 5 Gy as a significant threshold for an increased risk of in-field sarcoma occurrence.…”

Section: Retinoblastomamentioning

confidence: 99%

“…16 Yock et al 17 compared proton dosimetry to 3D-CRT photon plans (but not IMRT) for patients with orbital rhabdomyosarcoma and found that protons were superior because of reduced exposure to orbital structures, brain, and pituitary gland. In a treatment-planning comparison Lee et al 10 analyzed 3 cases of childhood pelvic sarcomas treated to doses ranging between 36 and 45 Gy. The single most important advantage found with the use of protons was the sparing of the ovaries.…”

Section: Pediatric Sarcomasmentioning

confidence: 99%

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Current status of radiotherapy with proton and light ion beams

Greco

Wolden

2007

Cancer

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Several model studies have shown potential clinical advantages with charged particles (protons and light ions) compared with 3D-conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) in many disease sites. The newly developed intensity-modulated proton therapy (IMPT) often yields superior dose distributions to photon IMRT, with the added advantage of a significant reduction in the volume of healthy normal tissues exposed to low-to-medium doses. Initially, the major emphasis in clinical research for proton and light ion therapy was dose escalation for inherently radioresistant tumors, or for lesions adjacent to critical normal structures that constrained the dose that could be safely delivered with conventional x-ray therapy. Since the advent of IMRT the interest in particle therapy has gradually shifted toward protocols aimed at morbidity reduction. Lately the emphasis has mostly been placed on the potential for reduced risk of radiation-induced carcinogenesis with protons. Compared with 3D-CRT, a 2-fold increase has been theoretically estimated with the use of IMRT due to the larger integral volumes. In the pediatric setting, due to a higher inherent susceptibility of tissues, the risk could be significant, and the benefits of protons have been strongly emphasized in the literature. There is a significant expansion of particle therapy facilities around the world. Increasing public awareness of the potential benefits of particle therapy and wider accessibility for patients require that treating physicians stay abreast of the clinical indications of this radiotherapy modality. The article reviews the available literature for various disease sites in which particle therapy has traditionally been considered to offer clinical advantages and to highlight current lines of clinical research. The issue of radiation-induced second malignancies is examined in the light of the controversial epidemiological evidence available. The cost-effectiveness of particle therapy is also discussed. Cancer 2007;109: 1227-38. 2007 American Cancer Society.KEYWORDS: radiotherapy, proton therapy, light ions, intensity modulated radiotherapy, second cancers. C harged particles (protons and light ions) have a finite range in tissues. The interaction probability to cause ionization increases as they lose velocity traversing through tissues, so that a peak of dose occurs at a depth proportional to the energy of each particle. Beyond this peak no further dose deposition occurs. This phenomenon was described by William Bragg over 100 years ago.1 The dose peak may be 'spread out' to achieve a plateau of uniform dose to precisely cover the target while sparing adjacent normal structures. Passively scattered beams of a certain aperture can be produced by means of range-shifting modulators of variable thickness providing spread-out Bragg peaks (SOBP) for clinical use. The recent introduction of the spot scanning method represents a major advance in particle therapy.2 In this method, small pencil beams of a certain

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Section: Central Nervous System Tumorssupporting

confidence: 89%

Section: Retinoblastomamentioning

confidence: 99%

Section: Pediatric Sarcomasmentioning

confidence: 99%

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Current status of radiotherapy with proton and light ion beams

Greco

Wolden

2007

Cancer

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“…The clinical target volume (CTV) was contoured to include the entire leptomeningeal region and the cranial contents (brain and meninges) and the spinal canal as described in previous studies [11,16]. The PTV was created by adding a uniform 5-mm volumetric margin to the CTV.…”

Section: Target Volume and Objectivesmentioning

confidence: 99%

Volumetric modulated arc therapy planning method for supine craniospinal irradiation

Chen¹,

Chen²,

Atwood³

et al. 2012

J Radiat Oncol

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Background The purpose of this study is to propose a volumetric modulated arc therapy (VMAT) treatment planning technique for supine craniospinal irradiation (CSI) in order to improve dose conformity and homogeneity, as well as the reliability of the matching of abutting fields. Methods and materials CT datasets of a 9-year-old child and a 24-year-old adult treated with supine CSI were identified. The planning target volume (PTV) was contoured to include the whole contents of the brain and spinal canal with a uniform margin of 5 mm. RapidArc plans were generated with two partial arcs covering the brain and the superior portion of the spinal cord and a single partial arc covering the remaining inferior portion of the spinal cord. Conformity and heterogeneity indexes (CI and HI) and organs at risk (OAR) dose-volume histograms were evaluated. The effect of treatment inaccuracy was simulated with intentional patient shifts of ±3 mm. Results The CI for the pediatric and adult cases was 1.0 and 0.99, respectively, and the HI for the two cases was 12.7 and 11.8 %, respectively. The mean dose to the PTV was 102.5 and 102.1 %, respectively, while the mean doses to the OARs were all low. The simulated ±3-mm shift in patient position generated an error of less than ±10 % of the calculated dose in the spinal cord. Conclusions VMAT CSI was able to achieve highly conformal and homogeneous dose distributions, with minor doses to the surrounding normal tissues. Setup errors of ±3 mm were shown to have little effect on the intended dose distribution.

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“…Proton radiotherapy is employed for delivery of craniospinal radiation in pediatric malignancies at several centers; this type of treatment allows radiation to be delivered to the brain and spinal cord with minimal exit dose through the heart, lungs and gastrointestinal and genitourinary organs. 74,75 Potential exists for the target volume to be expanded to include all of the skeletal bones as well as lymphoid groups and organs. To our knowledge, the dosimetric feasibility of this type of treatment has not been explored.…”

Section: Potential Use Of Proton Beam Radiotherapymentioning

confidence: 99%

TBI during BM and SCT: review of the past, discussion of the present and consideration of future directions

Hill‐Kayser

Plastaras

Tochner

et al. 2010

Bone Marrow Transplant

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TBI has been used widely in the setting of BMT over the past 3 decades. Early research demonstrated feasibility and efficacy in the myeloablative setting, in preparation first for allogenic BMT and later for autologous stem cell rescue. As experience with TBI increased, its dual roles of myeloablation and immunosuppression came to be recognized. Toxicity associated with myeloablative TBI remains significant, and this treatment is generally reserved for younger patients with excellent performance status. Reduced intensity conditioning regimens may be useful to provide immunosuppression for patients who are not candidates for myeloablative treatment. Efforts to reduce toxicity through protection of normal tissue using methods of normal tissue blocking and use of TLI, rather than TBI, continue. In the future, modalities such as helical tomotherapy, proton radiotherapy and radioimmunotherapy, may have roles in delivery of radiation to the BM and lymphoid structures with reduced normal tissue toxicity. With further investigation, these efforts may expand the therapeutic ratio associated with TBI, allowing safer delivery to a broader range of patients.

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Treatment planning with protons for pediatric retinoblastoma, medulloblastoma, and pelvic sarcoma: How do protons compare with other conformal techniques?

Cited by 223 publications

References 20 publications

Current status of radiotherapy with proton and light ion beams

Current status of radiotherapy with proton and light ion beams

Volumetric modulated arc therapy planning method for supine craniospinal irradiation

TBI during BM and SCT: review of the past, discussion of the present and consideration of future directions

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