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Proton and Proton-Photon Hybrid Partial Stereotactic Ablative Boost Radiotherapy (P-SABR) for Unresectable Large Tumors (LARGE-Proton)

9 septembre 2026 mis à jour par: Xian-shu Gao, Peking University First Hospital

A Prospective, Multicenter, Observational Cohort Study of Proton and Proton-Photon Hybrid Partial Stereotactic Ablative Boost Radiotherapy (P-SABR) for Unresectable Large Tumors

This prospective, multicenter, observational cohort study will enroll 60 adults with unresectable larege tumors (longest diameter > 5 cm) who receive one of two treatment modes: (A) proton P-SABR, in which both the proton partial-SABR boost (course 1) and the subsequent proton CFRT (course 2) are delivered at the proton center; or (B) proton-photon hybrid P-SABR, in which course 1 is delivered with protons at the proton center and course 2 CFRT is delivered with photons. The primary objective is to describe, in each cohort, the incidence of treatment-related grade ≥ 3 acute and late adverse events (CTCAE v5.0). Secondary objectives are dosimetric and the 1-year local control rate (RECIST 1.1, in-field). Participants are followed for up to 5 years.

Aperçu de l'étude

Description détaillée

BACKGROUND Large tumors (longest diameter > 5 cm) are often unresectable and respond poorly to conventionally fractionated radiotherapy (CFRT) because of their size and hypoxic core, while normal-tissue tolerance prevents delivering stereotactic ablative radiotherapy (SABR) to the whole tumor. Partial stereotactic ablative boost radiotherapy (P-SABR) delivers a SABR boost only to the central part of a large tumor, followed by CFRT to the whole target. Proton beams, with their Bragg-peak dose fall-off, may sharpen this "onion-skin" dose distribution and further increase the biologically effective dose (BED) within the tumor core.

DESIGN This prospective, multicenter, observational cohort study will enroll 60 adults with unresectable bulky tumors (longest diameter > 5 cm) who, as part of routine care, receive one of two treatment modes: (A) proton P-SABR, in which both the proton partial-SABR boost (course 1) and the subsequent proton CFRT (course 2) are delivered at the proton center; or (B) proton-photon hybrid P-SABR, in which course 1 is delivered with protons at the proton center and course 2 CFRT is delivered with photons (IMRT/VMAT) either at the same center or at Peking University First Hospital or one of six photon sub-centers, after central review of the composite plan. Cohort membership follows the patient's own choice and care pathway; the study does not assign treatment or intervene in clinical decisions, and no formal between-cohort hypothesis testing is planned.

OUTCOMES The primary objective is to describe, in each cohort, the incidence of treatment-related grade ≥ 3 acute and late adverse events (CTCAE v5.0). Secondary objectives are dosimetric (percentage of the GTV receiving BED10 ≥ 100 Gy, PTV V95% and V100%, organ-at-risk doses) and the 1-year local control rate (RECIST 1.1, in-field). Participants are followed for up to 5 years.

Type d'étude

Observationnel

Inscription (Estimé)

60

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Coordonnées de l'étude

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte
  • Adulte plus âgé

Accepte les volontaires sains

Non

Méthode d'échantillonnage

Échantillon non probabiliste

Population étudiée

Adults with histologically or cytologically confirmed, unresectable bulky solid tumors (at least one lesion with longest diameter > 5 cm) who present to the radiation oncology departments of the participating centers, and who elect to receive proton P-SABR (Cohort A) or proton-photon hybrid P-SABR (Cohort B). Eligible patients are enrolled consecutively after written informed consent.

La description

Inclusion Criteria:

  • Histologically or cytologically confirmed malignancy
  • At least one tumor with a longest diameter > 5 cm
  • Not amenable to curative surgical resection, or patient declines surgery, or surgery contraindicated because of medical comorbidities
  • Age ≥ 18 years
  • ECOG performance status 0-2
  • Life expectancy > 3 months
  • Written informed consent

Exclusion Criteria:

  • Prior radiotherapy to the same site
  • Severe cardiopulmonary insufficiency precluding radiotherapy
  • Concurrent other active malignancy
  • Uncontrolled acute infection or bowel obstruction
  • Pregnancy or breastfeeding
  • Intracranial lesion
  • Tumor directly invading the full thickness of the esophageal, gastric or intestinal wall with active ulceration, fistula or uncontrolled risk of perforation (tumors that only abut or displace a hollow organ without full-thickness invasion are not excluded)
  • Uncontrolled active tumor bleeding, or impending pathological fracture requiring orthopedic intervention
  • Any other condition that, in the investigator's judgment, makes the patient unsuitable for the study

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

Cohortes et interventions

Groupe / Cohorte
Intervention / Traitement
Cohort A: Proton P-SABR
Participants who receive the entire P-SABR course with protons at Hebei Yizhou Cancer Hospital: course 1, proton partial stereotactic ablative boost (intensity-modulated proton therapy, IMPT); course 2, proton conventionally fractionated radiotherapy (CFRT). Planned enrollment: 30.
Course 1 (proton partial-SABR boost, IMPT): CTV 1.8-3 Gy per fraction with a simultaneous boost to the boost volume within the GTV (GTVb) of 8 Gy × 3 fractions; in larger tumors the inner GTVb (GTVb shrunk by 1 cm) is further boosted to 12 Gy × 3 fractions; critical organs at risk < 3 Gy per fraction; robust optimization on the CTV. Course 2 (proton CFRT): CTV 1.8-3 Gy per fraction with robust optimization, to a cumulative PTV dose of 60-70 Gy on the summed plan, with GTVb BED10 ≥ 100 Gy. Proton dose is expressed with a constant RBE of 1.1. Both courses are delivered at Hebei Yizhou Cancer Hospital.
Autres noms:
  • Proton partial stereotactic ablative boost radiotherapy
  • Proton partial-SABR boost followed by proton conventionally fractionated radiotherapy
Cohort B: Proton-Photon Hybrid P-SABR
Participants who receive course 1 (proton partial stereotactic ablative boost, IMPT) at Hebei Yizhou Cancer Hospital, followed by course 2 photon conventionally fractionated radiotherapy (IMRT/VMAT with daily CBCT) delivered either at the same center (pathway A, same-center; planned n = 10) or at Peking University First Hospital or one of six photon sub-centers (pathway B, cross-center; planned n = 20) after central review of the composite plan. Planned enrollment: 30.
Course 1 identical to Cohort A: proton partial-SABR boost (IMPT) with GTVb 8 Gy × 3 fractions and inner GTVb 12 Gy × 3 fractions, delivered at Hebei Yizhou Cancer Hospital. Course 2 (photon CFRT): IMRT/VMAT with daily CBCT recommended, PTV 1.8-3 Gy per fraction to a cumulative PTV dose of 60-70 Gy on the summed plan, with GTVb BED10 ≥ 100 Gy, delivered at Hebei Yizhou Cancer Hospital (same-center) or at Peking University First Hospital or a photon sub-center (cross-center). For cross-center participants, DICOM-RT structure, plan and dose files of both courses are reviewed by the central radiotherapy QA committee, which performs deformable registration and dose summation (MIM; proton RBE = 1.1) before course 2 starts. Target interval between courses ≤ 3 working days (maximum 7 working days).
Autres noms:
  • Proton-photon hybrid partial stereotactic ablative boost radiotherapy
  • Proton partial-SABR boost followed by photon conventionally fractionated radiotherapy

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Incidence of treatment-related adverse events of grade ≥ 3 (CTCAE v5.0)
Délai: From the first fraction of radiotherapy to the end of the study
Up to 5 years after completion of radiotherapy (acute events: from the first fraction of radiotherapy through 90 days after completion; late events: from day 91 after completion through 5 years)
From the first fraction of radiotherapy to the end of the study

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Percentage of the gross tumor volume (GTV) receiving a biologically effective dose (BED10) ≥ 100 Gy
Délai: Up to 3 weeks after the first fraction of radiotherapy (when the composite plan of course 1 and course 2 is finalized)
Volume fraction (%) of the GTV receiving BED10 ≥ 100 Gy on the composite (summed) plan, extracted from the treatment planning system (proton dose converted with RBE = 1.1; dose summation in MIM ).
Up to 3 weeks after the first fraction of radiotherapy (when the composite plan of course 1 and course 2 is finalized)
Planning target volume (PTV) coverage: V95% and V100%
Délai: Up to 3 weeks after the first fraction of radiotherapy (when the composite plan of course 1 and course 2 is finalized)
Percentage of the PTV receiving ≥ 95% (V95%) and ≥ 100% (V100%) of the prescribed cumulative dose on the composite plan, reported per cohort as mean ± SD.
Up to 3 weeks after the first fraction of radiotherapy (when the composite plan of course 1 and course 2 is finalized)
Doses to organs at risk (OARs)
Délai: Up to 3 weeks after the first fraction of radiotherapy (when the composite plan of course 1 and course 2 is finalized)
Dose metrics of organs at risk (e.g., spinal cord maximum dose, esophagus, lung, bowel, brachial plexus) on the composite plan, and the proportion of participants meeting each OAR dose constraint, reported per OAR and per cohort with 95% CI.
Up to 3 weeks after the first fraction of radiotherapy (when the composite plan of course 1 and course 2 is finalized)
1-year local control (LC) rate
Délai: 12 months after the first fraction of radiotherapy
Local control is defined as the absence of progressive disease (RECIST 1.1) in in-field lesions; the in-field region is defined by the GTV/CTV/PTV projections exported from the treatment planning system (DICOM-RT) and confirmed by blinded central imaging review. Time to local progression is measured from the first fraction of radiotherapy. The 1-year LC rate and its Greenwood 95% CI are estimated per cohort with the Kaplan-Meier method; no between-cohort test is performed.
12 months after the first fraction of radiotherapy

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Publications et liens utiles

La personne responsable de la saisie des informations sur l'étude fournit volontairement ces publications. Il peut s'agir de tout ce qui concerne l'étude.

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Estimé)

1 octobre 2026

Achèvement primaire (Estimé)

1 décembre 2029

Achèvement de l'étude (Estimé)

1 décembre 2029

Dates d'inscription aux études

Première soumission

3 septembre 2026

Première soumission répondant aux critères de contrôle qualité

9 septembre 2026

Première publication (Réel)

14 septembre 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

14 septembre 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

9 septembre 2026

Dernière vérification

1 septembre 2026

Plus d'information

Termes liés à cette étude

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Description du régime IPD

Individual participant data will not be made publicly available because of Chinese regulations on health data and human genetic resources. De-identified data may be shared with qualified researchers on reasonable request to the principal investigator, subject to ethics committee approval.

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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