Retroperitoneal SarcomaPET-RPSNCT04224948
The PET- Retroperitoneal Sarcoma Study
A study testing PET MRI scan in people with Retroperitoneal Sarcoma, run by University Health Network, Toronto at 1 site in Canada.
Trial summary
Retroperitoneal sarcoma(RPS) is a rare cancer that is difficult to cure as it typically presents as a very large abdominal mass, and complete removal with clear margins is challenging . This study will focus on improving the outcomes of surgery by treating RPS before surgery, to make resection more effective. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Retroperitoneal Sarcoma
- What is being tested?
- PET MRI scan
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteCanada
- Study dates
- 3 Jan 2020to 31 Dec 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Tumour-related criteria
- Primary soft tissue sarcoma of retroperitoneal space or infra-peritoneal spaces of pelvis
- Sarcoma not originated from bone structure, abdominal or gynecological viscera
- Unifocal tumour (not multifocal disease)
- Absence of extension through the sciatic notch or across the diaphragm
- Histologically-proven RPS (local pathologist/ imaging-guided or surgical biopsy), only including the following histological sub-types:
Show all 34Show fewer
- High grade Leiomyosarcoma
- High grade Dedifferentiated Liposarcoma
- Tumour not previously treated (no previous surgery -excluding diagnosis biopsy-, radiotherapy or systemic therapy)
- Tumour both operable and suitable for chemotherapy (This will be based on pretreatment CT scan/MRI and multidisciplinary consultation with surgeon medical oncologist and radiologist (anticipated macroscopically complete resection, R0/R1resection)
- Patients for whom surgery is expected to be R2 on the CT-scan before randomization are not eligible
- Patients must have American Society of Anesthesiologist (ASA) score ≤ 2 (see Appendix G)
- The criteria for non-resectability are:
- (i) involvement of superior mesenteric artery
- (ii) involvement of aorta
- (iii) involvement of bone
- distant metastatic disease
- Patient must have radiologically measurable disease (RECIST 1.1)
- Patient-related criteria
- ≥ 18 years' old
- WHO performance status ≤ 2 (see Appendix C)
- Absence of history of bowel obstruction or mesenteric ischemia or severe chronic inflammatory bowel disease
- Normal renal function:
- Calculated creatinine clearance within normal value Functional contra-lateral kidney to the side involved by the RPS as assessed by intravenous pyelogram (done during the baseline CT-scan) or differential renal isotope scan
- Normal bone marrow and hepatic function:
- White Blood cells ≥ 2.5 x10 9 cells/L
- Platelets ≥ 80 x10 9 cells/L
- Total bilirubin < 1.5 time the institutional upper limit normal of value (ULN)
- Adequate cardiac function: less or equal to NYHA II
- Normal 12 lead ECG (without clinically significant abnormalities)
- No co-existing malignancy within the last 5 years except for adequately treated basal cell carcinoma of the skin or carcinoma in situ of the cervix
- No prior abdominal or pelvic irradiation for other prior malignancy or other disease
- Absence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule
- Excluding patients who presented after incomplete resection and underwent immediate completion surgery.
Who cannot join
- Age< 18 years
- Recurrent tumour
- Benign retroperitoneal tumours
- Presence of second active cancer
- Serious psychiatric disease that precludes informed consent or limits compliance
- impossible to ensure adequate follow up
Trial locations and contacts
1 site in 1 country.
Canada1 site
University Health Network and The Sinai Health System
Toronto, Ontario, M5G 1X5
About this study
Official title: The PET-RPS Study: Utility of PET for Assessment of Response to Preoperative Chemotherapy in Primary Retroperitoneal Sarcoma (RPS)
Retroperitoneal sarcoma(RPS) is a rare cancer that is difficult to cure as it typically presents as a very large abdominal mass, and complete removal with clear margins is challenging . This study will focus on improving the outcomes of surgery by treating RPS before surgery, to make resection more effective. The role of chemotherapy as a preoperative treatment for RPS is highly controversial. Response to chemotherapy is unpredictable and if the patient's tumour progresses instead of responding, the window of opportunity for resection will be lost. Conventional cross sectional imaging (CT scan) is inadequate to measure response to chemotherapy until 5-6 cycles have been given, possibly with no improvement. Thus it is critical to develop an earlier and reliable way to assess response. Functional imaging by PET scan is used in other tumour types to identify early response to treatment. PET imaging may provide a more meaningful assessment of RPS response to systemic therapy much earlier in the course of treatment than conventional imaging, allowing timely modification of the treatment plan. This study will define the role of PET imaging in evaluating early response to systemic therapy in high grade RPS, improving patient treatment.
Read the detailed description
Soft tissue sarcomas (STS) are derived from mesenchymal cells, and can arise at any site. Retroperitoneal sarcomas (RPS) account for ~15% of STS, and patients have much worse survival outcomes than for extremity STS. Local (abdominal) recurrence of RPS is very common, due to the challenges of obtaining complete resection of these large masses that abut critical central compartment structures, such as the inferior vena cava and aorta. There is currently intense interest in using preoperative therapy to downsize/cytoreduce RPS and hopefully improve oncologic outcomes. Studies have shown that preoperative radiation does not cytoreduce these tumours. In this study, the potential of systemic therapy for cytoreduction will be examined.
The standard systemic therapy regimen for treatment of patients with STS remains Adriamycin/Ifosphamide, although side effects can be tolerated only by relatively young and fit patients. The use of this regimen preoperatively for extremity STS results in average response rates of about 30-40%, as judged by histologic assessment of the resected specimen. The international experience with preoperative chemotherapy for RPS is very limited, and there are no published reports.
Functional imaging may provide a more meaningful assessment of tumour response to systemic therapy. PET-MR is a newer modality that may hold promise in assessing solid tumour response and its potential utility is currently of rapidly growing interest. Conventional MRI can offer a more detailed assessment of tumour relationships to adjacent structures than can CT, particularly in STS. Integration of PET with MR has the potential to provide information about metabolic tumour volume (MTV) and to help guide surgical planning.There are no data available on the utility of PET-MR in evaluating tumour response to chemotherapy in STS.
At present, the role of chemotherapy as a preoperative treatment for retroperitoneal sarcoma (RPS) is undefined and controversial. The sarcoma group at Princess Margaret Cancer Centre (PMCC) has had some experience with this treatment paradigm, but like most sarcoma groups in Ontario, and Canada, has reserved preoperative chemotherapy for frankly unresectable and borderline resectable tumours for which downsizing would potentially render resection more feasible. At present, CT-scan imaging is performed after 2 cycles of chemotherapy, and if there is no frank progression of the cancer, chemotherapy is continued for another 3-4 cycles. By that point the tumour is smaller on CT scan in about 30% of patients. There are 2 main problems with this approach: 1)70% of the patients may have undergone 5-6 cycles of chemotherapy with no apparent benefit; and 2) there may be a metabolic response and associated benefit without a change in tumour size. The ability to reliably assess tumour response earlier on (i.e. after 1 cycle) would significantly influence the care of these patients as ineffective chemotherapy could be terminated after 1 cycle and the regimen could be modified, or surgery could happen right away before the window of resectability is lost.
- Conditions
- Retroperitoneal Sarcoma
- Being tested
- PET MRI scan
- Keywords
- Retroperitoneal Sarcoma, Retroperitoneal, Sarcoma, Neoadjuvant Chemotherapy, preoperative Chemotherapy
- Medical subject headings
- Sarcoma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PET MRI scanDevice
Standard of care includes a baseline PET-CT and conventional CT after 2 cycles of neoadjuvant chemotherapy, and after 5-6 cycles, of neoadjuvant chemotherapy, as per current practice/ standard of care.
Patients that enroll in the trial will receive two additional PET MRI scans- one at baseline and one after 1 cycle of chemotherapy
| Study group | Role | What they receive |
|---|---|---|
| PET-MR arm | Experimental | Every eligible patient will be scanned by PET-MR at baseline and following 1 cycle of chemotherapy. PET-CT at baseline will also be obtained as it is the current standard of care and will be used to determine trial eligibility (no evidence metastasis at baseline). Receives: Device: PET MRI scan |
What is being measured
The primary outcome is the main question the study is designed to answer.
Correlation of PET imaging with histologic response following preoperative chemotherapy.
Pathology of RPS specimens, resected following standard ifosfamide/doxorubicin chemotherapy every 3 weeks for 5-6 cycles, will be compared with PET response (FDG uptake) after cycle 1 of chemotherapy.
Measured: 3 years
Secondary outcomes (1)
Correlation of CT imaging with histologic response, and comparing prognostic accuracy of PET-MR vs.CT imaging for histologic response, recurrence status, and survival.
Pathology of resected RPS specimens, resected following standard ifosfamide/doxorubicin chemotherapy every 3 weeks for 5-6 cycles, will be compared with CT response after 2 and 5/6 cycles of preoperative chemotherapy. PET imaging and CT imaging will be compared as prognosticators of histological response, recurrence and survival.
Measured: 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Jan 2020
- Study start3 Jan 2020
- Primary completion31 Dec 2024
- Study completion31 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Retroperitoneal SarcomaStudies of the same condition, open and under way.
- More trials run by University Health Network, TorontoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Screening
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Health Network, Toronto
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Carol Swallow, MD, PhD, Principal investigator, Sinai Health System
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04224948
- Sponsor's protocol ID
- 19-5429
- Acronym
- PET-RPS
- Status last verified
- Nov 2025
- First submitted
- 4 Jul 2019
- Last updated
- 3 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The PET-RPS Study: Utility of PET for Assessment of Response to Preoperative Chemotherapy in Primary Retroperitoneal Sarcoma (RPS)
- ClinicalTrials.gov ID
- NCT04224948
- Acronym / sponsor ID
- PET-RPS / 19-5429
- Conditions
- Retroperitoneal Sarcoma
- Keywords
- Retroperitoneal Sarcoma, Retroperitoneal, Sarcoma, Neoadjuvant Chemotherapy, preoperative Chemotherapy
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- University Health Network, TorontoUniversity, hospital or other
- Study start
- 3 Jan 2020 (actual)
- Primary completion
- 31 Dec 2024 (actual)
- Study completion
- 31 Dec 2024 (actual)
- First posted
- 13 Jan 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Retroperitoneal sarcoma(RPS) is a rare cancer that is difficult to cure as it typically presents as a very large abdominal mass, and complete removal with clear margins is challenging . This study will focus on improving the outcomes of surgery by treating RPS before surgery, to make resection more effective. The role of chemotherapy as a preoperative treatment for RPS is highly controversial. Response to chemotherapy is unpredictable and if the patient's tumour progresses instead of responding, the window of opportunity for resection will be lost. Conventional cross sectional imaging (CT scan) is inadequate to measure response to chemotherapy until 5-6 cycles have been given, possibly with no improvement. Thus it is critical to develop an earlier and reliable way to assess response. Functional imaging by PET scan is used in other tumour types to identify early response to treatment. PET imaging may provide a more meaningful assessment of RPS response to systemic therapy much earlier in the course of treatment than conventional imaging, allowing timely modification of the treatment plan. This study will define the role of PET imaging in evaluating early response to systemic therapy in high grade RPS, improving patient treatment.
Detailed description
Soft tissue sarcomas (STS) are derived from mesenchymal cells, and can arise at any site. Retroperitoneal sarcomas (RPS) account for ~15% of STS, and patients have much worse survival outcomes than for extremity STS. Local (abdominal) recurrence of RPS is very common, due to the challenges of obtaining complete resection of these large masses that abut critical central compartment structures, such as the inferior vena cava and aorta. There is currently intense interest in using preoperative therapy to downsize/cytoreduce RPS and hopefully improve oncologic outcomes. Studies have shown that preoperative radiation does not cytoreduce these tumours. In this study, the potential of systemic therapy for cytoreduction will be examined.
The standard systemic therapy regimen for treatment of patients with STS remains Adriamycin/Ifosphamide, although side effects can be tolerated only by relatively young and fit patients. The use of this regimen preoperatively for extremity STS results in average response rates of about 30-40%, as judged by histologic assessment of the resected specimen. The international experience with preoperative chemotherapy for RPS is very limited, and there are no published reports.
Functional imaging may provide a more meaningful assessment of tumour response to systemic therapy. PET-MR is a newer modality that may hold promise in assessing solid tumour response and its potential utility is currently of rapidly growing interest. Conventional MRI can offer a more detailed assessment of tumour relationships to adjacent structures than can CT, particularly in STS. Integration of PET with MR has the potential to provide information about metabolic tumour volume (MTV) and to help guide surgical planning.There are no data available on the utility of PET-MR in evaluating tumour response to chemotherapy in STS.
At present, the role of chemotherapy as a preoperative treatment for retroperitoneal sarcoma (RPS) is undefined and controversial. The sarcoma group at Princess Margaret Cancer Centre (PMCC) has had some experience with this treatment paradigm, but like most sarcoma groups in Ontario, and Canada, has reserved preoperative chemotherapy for frankly unresectable and borderline resectable tumours for which downsizing would potentially render resection more feasible. At present, CT-scan imaging is performed after 2 cycles of chemotherapy, and if there is no frank progression of the cancer, chemotherapy is continued for another 3-4 cycles. By that point the tumour is smaller on CT scan in about 30% of patients. There are 2 main problems with this approach: 1)70% of the patients may have undergone 5-6 cycles of chemotherapy with no apparent benefit; and 2) there may be a metabolic response and associated benefit without a change in tumour size. The ability to reliably assess tumour response earlier on (i.e. after 1 cycle) would significantly influence the care of these patients as ineffective chemotherapy could be terminated after 1 cycle and the regimen could be modified, or surgery could happen right away before the window of resectability is lost.
Study design
- Primary purpose
- Screening
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| PET-MR arm | Experimental | Device: PET MRI scanEvery eligible patient will be scanned by PET-MR at baseline and following 1 cycle of chemotherapy. PET-CT at baseline will also be obtained as it is the current standard of care and will be used to determine trial eligibility (no evidence metastasis at baseline). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (34 listed)
- Tumour-related criteria
- Primary soft tissue sarcoma of retroperitoneal space or infra-peritoneal spaces of pelvis
- Sarcoma not originated from bone structure, abdominal or gynecological viscera
- Unifocal tumour (not multifocal disease)
- Absence of extension through the sciatic notch or across the diaphragm
Key exclusion criteria (6 listed)
- Age< 18 years
- Recurrent tumour
- Benign retroperitoneal tumours
- Presence of second active cancer
- Serious psychiatric disease that precludes informed consent or limits compliance
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PET MRI scanStandard of care includes a baseline PET-CT and conventional CT after 2 cycles of neoadjuvant chemotherapy, and after 5-6 cycles, of neoadjuvant chemotherapy, as per current practice/ standard of care. Patients that enroll in the trial will receive two additional PET MRI scans- one at baseline and one after 1 cycle of chemotherapy | Device | PET-MR arm |
Primary outcome
Correlation of PET imaging with histologic response following preoperative chemotherapy.
Time frame: 3 years
Pathology of RPS specimens, resected following standard ifosfamide/doxorubicin chemotherapy every 3 weeks for 5-6 cycles, will be compared with PET response (FDG uptake) after cycle 1 of chemotherapy.
1 secondary outcome
Correlation of CT imaging with histologic response, and comparing prognostic accuracy of PET-MR vs.CT imaging for histologic response, recurrence status, and survival.
Time frame: 3 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Dec 2025.
- Individual participant dataSharing planned: No
Related trials for Retroperitoneal Sarcoma
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Carol Swallow, MD, PhD principal investigator
Sinai Health System
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing PET MRI scan in people with Retroperitoneal Sarcoma, run by University Health Network, Toronto at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 34 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Correlation of PET imaging with histologic response following preoperative chemotherapy. (time frame: 3 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Dec 2025.