Potential benefits of adaptive intensity‐modulated proton therapy in nasopharyngeal carcinomas

Minatogawa, Hideki; Yasuda, Kôichi; Dekura, Yasuhiro; Sugiyama, Takao; Matsuura, Tetsuya; Yoshimura, Takaaki; Suzuki, Ryusuke; Yokota, Isao; Fujima, Noriyuki; Onimaru, Rikiya; Shimizu, Satoru; Aoyama, Hidefumi; Shirato, Hiroki

doi:10.1002/acm2.13128

Cited by 14 publications

(24 citation statements)

References 29 publications

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“…All recurrences were observed in the high dose region [ 12 ]. Minatogawa et al compared the results of adaptive IMRT with adaptive IMPT and showed a statistically significant reduction in the

of the right parotid gland, both temporomandibular joints, the oral cavity, the larynx (all with

) and thyroid gland (

) when using adaptive IMPT [ 18 ]. The retrospective study by Placidi et al reported about plan adaptations in 5.5% of the studied cases, which were treated with PBS, as a result of anatomical changes during the PT course.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, the need for adaptive proton therapy (APT) planning needs to be evaluated. Previous studies pointed out the need to account for anatomical changes during the course of RT [ 10 , 12 , 13 , 14 ] and particularly PT treatment [ 15 , 16 , 17 , 18 ], especially for tumors of the head and neck. There is clearly less corresponding evidence for PT of pediatric patients.…”

Section: Introductionmentioning

confidence: 99%

“…The current study can add its early experiences to Refs. [ 10 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ] by prospectively evaluating adaptive high precision PT in children with head and neck or base of skull tumors. The aim of the study is to explore the potential benefits of APT based on sCTs, which are generated with verification MRIs.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Proton Therapy of Pediatric Head and Neck Cases Using MRI-Based Synthetic CTs: Initial Experience of the Prospective KiAPT Study

Bäumer

Frakulli

Kohl

et al. 2022

Cancers

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Background and Purpose: Interfractional anatomical changes might affect the outcome of proton therapy (PT). We aimed to prospectively evaluate the role of Magnetic Resonance Imaging (MRI) based adaptive PT for children with tumors of the head and neck and base of skull. Methods: MRI verification images were acquired at half of the treatment course. A synthetic computed tomography (CT) image was created using this MRI and a deformable image registration (DIR) to the reference MRI. The methodology was verified with in-silico phantoms and validated using a clinical case with a shrinking cystic hygroma on the basis of dosimetric quantities of contoured structures. The dose distributions on the verification X-ray CT and on the synthetic CT were compared with a gamma-index test using global 2 mm/2% criteria. Results: Regarding the clinical validation case, the gamma-index pass rate was 98.3%. Eleven patients were included in the clinical study. The most common diagnosis was rhabdomyosarcoma (73%). Craniofacial tumor site was predominant in 64% of patients, followed by base of skull (18%). For one individual case the synthetic CT showed an increase in the median D2 and Dmax dose on the spinal cord from 20.5 GyRBE to 24.8 GyRBE and 14.7 GyRBE to 25.1 GyRBE, respectively. Otherwise, doses received by OARs remained relatively stable. Similarly, the target volume coverage seen by D95% and V95% remained unchanged. Conclusions: The method of transferring anatomical changes from MRIs to a synthetic CTs was successfully implemented and validated with simple, commonly available tools. In the frame of our early results on a small cohort, no clinical relevant deterioration for neither PTV coverage nor an increased dose burden to OARs occurred. However, the study will be continued to identify a pediatric patient cohort, which benefits from adaptive treatment planning.

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“…All recurrences were observed in the high dose region [ 12 ]. Minatogawa et al compared the results of adaptive IMRT with adaptive IMPT and showed a statistically significant reduction in the

of the right parotid gland, both temporomandibular joints, the oral cavity, the larynx (all with

) and thyroid gland (

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Adaptive Proton Therapy of Pediatric Head and Neck Cases Using MRI-Based Synthetic CTs: Initial Experience of the Prospective KiAPT Study

Bäumer

Frakulli

Kohl

et al. 2022

Cancers

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“…The key role played by RT has been recently strengthened by the introduction of proton therapy (PT) as a RT treatment option for head and neck cancer (HNC), including NPC [ 8 ]. In particular, intensity-modulated proton therapy (IMPT) has the possibility to reduce radiation-induced side-effects to organs-at-risk (OARs) while guaranteeing highly conformal coverage of the target compared to advanced photon-based RT techniques, such as volumetric modulated arc therapy (VMAT) [ 9 ]. Planned comparison studies between IMPT and IMRT techniques have suggested that lower (mean) doses can be delivered to several organs at risk (OARs) in patients with NPC [ 10 , 11 , 12 , 13 ], without significant difference in target coverage, conformity, or homogeneity indexes [ 10 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Proton Radiation Therapy for Nasopharyngeal Cancer Patients: Dosimetric and NTCP Evaluation Supporting Clinical Decision

Vai

Molinelli

Rossi

et al. 2022

Cancers

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(1) Background: we proposed an integrated strategy to support clinical allocation of nasopharyngeal patients between proton and photon radiotherapy. (2) Methods: intensity-modulated proton therapy (IMPT) plans were optimized for 50 consecutive nasopharyngeal carcinoma (NPC) patients treated with volumetric modulated arc therapy (VMAT), and differences in dose and normal tissue complication probability (ΔNTCPx-p) for 16 models were calculated. Patient eligibility for IMPT was assessed using a model-based selection (MBS) strategy following the results for 7/16 models describing the most clinically relevant endpoints, applying a model-specific ΔNTCPx-p threshold (15% to 5% depending on the severity of the complication) and a composite threshold (35%). In addition, a comprehensive toxicity score (CTS) was defined as the weighted sum of all 16 ΔNTCPx-p, where weights follow a clinical rationale. (3) Results: Dose deviations were in favor of IMPT (ΔDmean ≥ 14% for cord, esophagus, brainstem, and glottic larynx). The risk of toxicity significantly decreased for xerostomia (−12.5%), brain necrosis (−2.3%), mucositis (−3.2%), tinnitus (−8.6%), hypothyroidism (−9.3%), and trismus (−5.4%). There were 40% of the patients that resulted as eligible for IMPT, with a greater advantage for T3–T4 staging. Significantly different CTS were observed in patients qualifying for IMPT. (4) Conclusions: The MBS strategy successfully drives the clinical identification of NPC patients, who are most likely to benefit from IMPT. CTS summarizes well the expected global gain.

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“…Nonetheless, a predictive replan approach can offer advantages in improving clinical workflow efficiency. Intensity modulated proton therapy (IMPT) offers the potential to limit dose to normal tissues for head and neck (H&N) cancer patients [1][2][3][4][5]. However, this precise delivery technique has inherent sensitivity to uncertainties.…”

Section: Introductionmentioning

confidence: 99%

Improving workflow for adaptive proton therapy with predictive anatomical modelling: A proof of concept

Zhang

Alshaikhi

Amos

et al. 2022

Radiotherapy and Oncology

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Potential benefits of adaptive intensity‐modulated proton therapy in nasopharyngeal carcinomas

Cited by 14 publications

References 29 publications

Adaptive Proton Therapy of Pediatric Head and Neck Cases Using MRI-Based Synthetic CTs: Initial Experience of the Prospective KiAPT Study

Adaptive Proton Therapy of Pediatric Head and Neck Cases Using MRI-Based Synthetic CTs: Initial Experience of the Prospective KiAPT Study

Proton Radiation Therapy for Nasopharyngeal Cancer Patients: Dosimetric and NTCP Evaluation Supporting Clinical Decision

Improving workflow for adaptive proton therapy with predictive anatomical modelling: A proof of concept

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