Observational Study on Extreme Hypofractionation for Localized Prostate Cancer
OBELIX PCa
1 other identifier
observational
246
1 country
1
Brief Summary
Radiotherapy (RT) is an established treatment option for localized prostate cancer (PCa), with cure rates similar to those of radical prostatectomy. In the last decade, conventionally fractionated RT (1.8-2.0 Gy per fraction to 78-80 Gy) has been replaced by moderately hypofractionated RT (2.3-3.65 Gy per fraction to 56-70 Gy). The rationale behind this change is the scientific level 1 evidence that a higher dose per fraction may improve the cost-benefit of RT due to the specific radiobiology of PCa (a lower alpha/beta than that of adjacent healthy tissues). Additionally, there is a practical advantage both for patients and the radiation department due to a reduced number of fractions. More recently, extreme hypofractionation or stereotactic body radiotherapy (SBRT) (7-9.5 Gy per fraction to 36-43 Gy in 4-7 fractions) has been introduced as RT modality, and proved to be an effective and safe treatment option for patients with low and intermediate clinically-localized PCa, with similar incidence of late toxicity and 5-year disease free survival outcomes when compared to hypofractionated and conventional radiotherapy regimens. International guidelines endorse extreme hypofractionated SBRT as routine treatment option for low and intermediate risk PCa patients. For high-risk prostate cancer, preliminary results of ongoing prospective studies are promising, but these data are not yet mature enough to recommend extreme hypofractionated SBRT in high-risk prostate cancer. Upon this, ongoing prospective trials handle strict eligibility criteria hereby selecting patients with few comorbidities. This may not necessarily fully reflect the real life patient population. Indeed, patients with a large prostate size, a history of transurethral resection of the prostate (TURP), or 'significant' urinary baseline symptoms may be at risk for experiencing increased toxicity. Based on this concern, these patients were excluded from ongoing clinical trials. However, whether these patients will really develop more toxicity, is a theoretical concern, not yet based on clinical evidence. It is our hypothesis that using modern radiotherapy such as volumetric arc therapy (VMAT) and image-guided radiotherapy (IGRT) - both standard technologies at the Radiation-Oncology department in Leuven University Hospitals - extreme hypofractionated SBRT can be successfully implemented in the treatment of intermediate risk and a select group of high-risk PCa patients and/or patients with pre-existing urinary morbidity.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for all trials
Started Apr 2022
Longer than P75 for all trials
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
April 12, 2022
CompletedFirst Posted
Study publicly available on registry
April 25, 2022
CompletedStudy Start
First participant enrolled
April 25, 2022
CompletedPrimary Completion
Last participant's last visit for primary outcome
April 1, 2027
ExpectedStudy Completion
Last participant's last visit for all outcomes
April 1, 2032
March 30, 2025
March 1, 2025
4.9 years
April 12, 2022
March 25, 2025
Conditions
Outcome Measures
Primary Outcomes (1)
acute toxicity
acute gastrointestinal (GI) and genitourinary (GU) Common Terminology Criteria for Adverse Events version 5.0 (CTCAE 5.0)
toxicity occurring within 90 days after the first SBRT session
Secondary Outcomes (4)
late toxicity
90 days to 5 years after the last radiation treatment
impact on quality if of life
until month 60
(Biochemical and Clinical) Relapse-free survival
until month 60
Dose-volume parameters
until month 60
Interventions
stereotactic radiotherapy of the primary prostate
Eligibility Criteria
localized intermediate or high risk prostate cancer (Roach formule \< 35%) (cT1-3a/b cN0 M0)
You may qualify if:
- men ≥ 18 years
- histologically confirmed clinically localized adenocarcinoma of the prostate
- intermediate- or high-risk PCa, defined as
- OR at least one of the following criteria:
- clinical stage: cT2a-c, cT3a or cT3b (AJCC 7th edition)
- Gleason Score ≥ 7 (ISUP grade group 2 or higher)
- OR at least two of the following criteria:
- clinical stage: cT1c (AJCC 7th edition)
- Gleason Score ≥ 7 (ISUP grade group 2 or higher)
- calculated risk for lymph node involvement (Roach formula) \<35%.
- no evidence of disease spread beyond the prostate and/or seminal vesicles
- imaging with mpMRI of the prostate and pelvis (compliant with the PIRADS v2.1 guidelines) within 90 days prior to registration, or required to be performed after registration to the trial
- ability to understand, and willingness to sign, the written informed consent
- willingness to comply with scheduled visits, treatment, and other procedures
You may not qualify if:
- prior pelvic irradiation (external beam radiotherapy or brachytherapy)
- previous radical prostatectomy, cryosurgery, or HIFU for prostate cancer
- previous or concurrent cytotoxic chemotherapy for prostate cancer
- patients with neuroendocrine or small cell carcinoma of the prostate
- clinical stage cT4 (invasion of adjacent organ like bladder or rectum, visualized on mpMRI and/or ultrasound and endoscopy) (AJCC 7th edition)
- significant urinary obstruction of other voiding symptoms (IPSS \> 18) is allowed, however should be discussed with the principal investigator and left to the discretion of the treating physician
- high risk of lymph node involvement, as calculated with the Roach formula ≥ 35% (https://www.evidencio.com/models/show/1144) Of note, in case of ambiguity of regional lymph node involvement on CT or MRI findings (when Roach formula is \< 35%, and all other eligibility criteria are met), dedicated imaging with PSMA PET-CT or extended pelvic lymph node dissection must be obtained to rule out lymph node involvement
- evidence of distant metastases (based on CT scan, MRI of the pelvis, bone scan within 90 days prior to registration; if the bone scan is suspicious but not unequivocal, dedicated X-ray and/or MRI must be obtained to rule out metastasis)
- contraindications to MRI according to the Radiology Department guidelines (metal implants, noncompatible cardiac device, deep brain stimulators, cochlear implants, metallic foreign body in the eye or aneurysm clips in the brain, severe claustrophobia).
- World Health Organization (WHO) performance score \> 2
- patients with severe inflammatory bowel disease rendering radiotherapy impossible (active Crohn's Disease or Ulcerative Colitis), or patients known with ataxia telangiectasia
- implanted hardware or other material that would prohibit appropriate treatment planning or treatment delivery, in the investigator's opinion
- prior or concurrent invasive malignancy (except non-melanomatous skin cancer) or lymphomatous/hematogenous malignancy unless continually disease-free for a minimum of 5 years.
- (carcinoma in situ of the bladder or oral cavity is permissible)
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
UZ Leuven
Leuven, Vlaams Brabant, 3000, Belgium
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Gert De Meerleer, MD, PhD
UZ Leuven
Central Study Contacts
Study Design
- Study Type
- observational
- Observational Model
- COHORT
- Time Perspective
- PROSPECTIVE
- Target Duration
- 5 Years
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
April 12, 2022
First Posted
April 25, 2022
Study Start
April 25, 2022
Primary Completion (Estimated)
April 1, 2027
Study Completion (Estimated)
April 1, 2032
Last Updated
March 30, 2025
Record last verified: 2025-03
Data Sharing
- IPD Sharing
- Will not share
no sharing of IPD due to GDPR