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.
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
Prior radiotherapy to the same site
Severe cardiopulmonary insufficiency precluding radiotherapy
Concurrent other active malignancy
Uncontrolled acute infection or bowel obstruction
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.
Cohort
Prospective
Proton P-SABR
RadiationCourse 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.
Proton-Photon Hybrid P-SABR
RadiationCourse 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).
Incidence of treatment-related adverse events of grade ≥ 3 (CTCAE v5.0)
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)
Percentage of the gross tumor volume (GTV) receiving a biologically effective dose (BED10) ≥ 100 Gy
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 ).
Planning target volume (PTV) coverage: V95% and V100%
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.
Doses to organs at risk (OARs)
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.
1-year local control (LC) rate
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.
Click on the lead sponsor to view all of their trials.
This trial is not recruiting at the moment. You can still explore other options:
