The purpose of the study is to study if dose escalated proton radiotherapy can improve local controll for patients with inoperable soft tissue sarcomas. The standard treatment is photon-based radiation. By using proton radiotherapy instead, the hypothesis is that the dose can be increased to enhance treatment effectiveness without increasing side effects. The planned radiation dose is 56 Gy in 16 fractions (treatments) over 4 weeks (4 fractions per week), with a maximum dose escalation centrally in the tumor up to 80 Gy (5 Gy per fraction). At the same time, the study will investigate biomarkers that can predict treatment response, including changes in the tumor's genetic material (DNA), measurements of various molecules in the bloodstream, and the tumor's appearance on MRI scans. The primary endpoint is local control after 2 years, meaning that the treated tumor has not grown during this period. Secondary endpoints include overall survival, progression-free survival, radiological response rates, side effects, and quality of life. The study will be conducted in Norway, with a planned inclusion of 40 patients.
The objective of the PROSARC-2 trial is to investigate whether dose-escalated hypofractionated, definitive, proton beam therapy (PBT) can result in better local control in soft tissue sarcoma (STS). PROSARC-2 is a single arm, open-label, multicenter phase II clinical trial initiated at the Department of Oncology, Oslo University Hospital (OUS). The main inclusion criterion is patients with inoperable soft tissue sarcoma. The primary endpoint is 2-year local progression-free survival (LPFS). We expect to include 40 patients over three years and all patients will be followed for up to five years. All the sarcoma centers in Norway participate in the study: OUS; Haukeland University Hospital (HUH); St Olavs Hospital (SOH) and University Hospital of North-Norway (UNN). The indication for definitive radiotherapy (RT) will be decided in the sarcoma multidisciplinary (MDT) meeting at each center. A weekly/biweekly national sarcoma RT meeting will make the decision whether hypofractionated, dose-escalated PBT will be feasible after a careful clinical evaluation. For included patients PBT will be given at OUS and HUH. The prescribed dose is 56 Gray (Gy) in 16 fractions over 4 weeks (14 Gy per week) with a maximum dose-escalation to the tumor core of 80 Gy (5 Gy per fraction). The PROSARC-2 trial includes translational radiomic research, where we aim to elucidate underlying mechanisms related to RT effect. To facilitate future biomarker studies for personalized therapy we will collect excess tumor tissue, whole blood, plasma and serum.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
40
The prescribed dose is 56 Gray (Gy) in 16 fractions over 4 weeks (14 Gy per week) with a maximum dose-escalation to the tumor core of 80 Gy (5 Gy per fraction).
Haukeland University Hospital
Bergen, Norway
NOT_YET_RECRUITINGOslo University Hospital
Oslo, Norway
RECRUITINGLocal progression-free survival
Local progression-free survival is measured from the date of start of study treatment until date of local progression of the tumor that has undergone proton beam radiotherapy evaluated using RECIST v1.1 or date of death of any cause, whichever occurs first.
Time frame: 2 Year
Progression-free survival
Progression-free survival is measured from the date of start of study treatment until date of progressive disease (local and/or distant) as evaluated using RECIST v1.1 or date of death of any cause, whichever occurs first.
Time frame: Up to five years after radiation therapy
Overall survival
Overall survival is measured from the date of start of study treatment until date of death of any cause.
Time frame: Up to five years after radiation therapy.
Overall response rate, defined as partial or complete response using RECIST v1.1
Radiological response will be assessed using MRI and/or CT of the primary tumor.
Time frame: Up to five years after radiation therapy.
Health-related quality of life
Change from baseline in EORTC QLQ-C30 scores.
Time frame: Up to five years after radiation therapy.
To assess acute and late toxicity
Treatment-related toxicity during treatment and follow-up using CTCAE v5.0.
Time frame: Up to five years after radiation therapy.
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