An observational study in Prostate Cancer, Prostate Cancer Metastatic Disease and Prostate Cancer Recurrent, sponsored by Maastricht Radiation Oncology. Recruiting at 3 sites in Netherlands. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-23.
Sponsored by Maastricht Radiation Oncology · Observational
For men with an aggressive form of prostate cancer, finding the right and effective treatment right away is challenging. Many of these men face a high risk of cancer recurrence: about half experience a relapse after surgery, and more than a third after undergoing radiation therapy. Men with metastatic prostate cancer have particularly poor prognoses, with a five-year survival rate of only 30% to 50%. In short, it is difficult to predict which treatment, or combination of treatments, will lead to longer survival for this group of men with aggressive (metastatic) prostate cancer.
In the laboratory, it is possible to grow small samples of tumors into 3D mini-tumors. These mini-tumors retain the characteristics of the patient's original tumor tissue. Various treatments can be tested on these 3D mini-tumors to determine which therapy is most effective for each individual case. There are currently two techniques available for creating these 3D mini-tumors in the lab. In this project, we aim to investigate which of these two techniques works best in order to test and personalize treatments.
The biological diversity of high-risk prostate cancer makes it difficult to find an effective first-line or second-line cancer treatment. Therapy failure is high for men with high-risk localized cancer, having a risk of a biochemical relapse between 42% and 50% following radical prostatectomy and 36-43% after radiation therapy. Moreover, very high-risk prostate cancers with distant metastasis, accounting for 22% of the prostate cancer diagnoses, have a worse prognosis with overall 5-year survival rates of only 30-45%. Personalized treatment plans based on ex vivo therapy testing on patient-derived prostate cancer cultures could offer a more tailored approach by predicting the most effective therapy for each patient's specific tumor profile.
Ex vivo patient-derived 3D cultures may be an excellent solution which is able to recapitulate histological characteristics of the original tumor and could be utilized to assess tumorigenesis, potential drug targets and patients' drug responsiveness. Aside from the preservation of histological characteristics of the original tumor, ex vivo patient-derived 3D cultures are able to maintain physiological tumor features by preservation of the tumor micro-environment which is essential for testing selected types of anti-cancer drugs. Ex vivo patient-derived 3D cultures are generated from small fragments of tumor tissue containing organ-specific (tumor) cell types, which are cultivated into miniature, self-organizing prostate tumors using one of two principal techniques: organoid (i.e., utilizing a basement membrane exact) or tumor replica technology (i.e., utilizing a suspension culture without matrix support). Success rates of culturing prostate cancer organoids based on left-over tissue after radical prostatectomy are excellent, varying between 90% and 98%, however, for the more high-risk (metastasized) prostate cancers, the success rates vary considerably from 16% to 44% based on the small amount of needle biopsy tissue and inherent low cellular yield, limited cell-cell interaction, or prostate cancer subtype specific growth factors.
To overcome the above-mentioned low success-rates, the high turnaround time, and challenges of deriving (metastasized) prostate cancer organoids, the tumor replica technology may be interesting to explore. The tumor replica technology is optimized by Rianne Vaes at the Maastro Lab in the IPON-3 study for lung cancer (NL79010.068.21) and has increased the success rate from 17% to 70% (unpublished). So far, only one study generated prostate cancer tumor replicas utilizing this technique and showed an excellent success rate of 100% after radical prostatectomy. However, the establishment and use of tumor replicas derived from high-risk (metastatic) prostate cancer biopsies have been described yet, nor have been from prostate cancer recurrence following initial radiation therapy (i.e. radioresistant prostate cancer). Moreover, only one study demonstrated the capability of predicting the therapy response for prostate cancer drugs as well as radiation therapy on patient-derived 3D organoids of treatment-naïve prostate cancer patients utilizing left-over prostatectomy tissue. The number of patients on which treatment responsiveness was tested, however, was low (3 patients tested for prostate cancer drugs and 2 for radiation therapy).
7,046 studies on the registry are indexed under Prostatic Neoplasms; 1,580 are open to participants now.
This study's planned enrollment of 600 is above the median of 200 across 1,310 observational studies indexed under Prostatic Neoplasms.
Browse Prostatic Neoplasms studies →Maastricht Radiation Oncology is the lead sponsor of 106 studies on the registry; 9 are open to participants now.
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Patients planned for HDR brachytherapy treatment for high-risk or recurrent prostate cancer or transperineal prostate biopsy with MRI-suspected metastatic prostate cancer with at least clinical stage T3-4.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
High-risk or recurrent prostate cancer patients that will undergo high dose rate (HDR) brachytherapy.
Procedure: HDR brachytherapy
Patients with MRI-suspected metastatic prostate cancer - with at least clinical stage T3-4 disease - that will undergo a diagnostic transperineal prostate biopsy procedure guided with ultrasound (i.e., targeted or template prostate cancer needle biopsies taken through the perineum guided with transrectal ultrasound)
Diagnostic Test: Diagnostic biopsy
High dose rate (HDR) brachytherapy for the treatment of high-risk or recurrent prostate cancer
Transperineal prostate biopsies guided with transrectal ultrasound for the diagnosis of (recurrent) prostate cancer
Success rate
Determine the success rate of the established ex vivo prostate cancer 3D cultures from patient-derived (tumor) tissue material in which at least one first-line or second-line prostate cancer treatment (encompassing radiation exposure or cancer drugs) has been tested for sensitivity within a clinically relevant timeframe (up to 2 months).
Time frame: 1 year
Most successful culturing technique per subtype
Evaluate the most successful culturing technique (organoid versus tumor replica) per prostate cancer subtype (e.g., different morphologies such as adenocarcinoma, carcinoid or neuroendocrine features; various tumor stages) for generating ex vivo patient-derived prostate cancer 3D cultures from biopsy tissue along with subsequent testing of first-line, second-line or novel/personalized prostate cancer treatments.
Time frame: 1 year
(epi)genetic and phenotypic tumor features
To investigate the stability of (epi-) genetic and phenotypic tumor features of patient-derived 3D prostate cancer cultures compared to the tumor of origin using, for example, H\&E staining or immunohistochemistry stainings.
Time frame: 1 year
Treatment response
Compare the preclinical ex vivo patient-derived prostate cancer 3D culture predicted treatment sensitivity to prostate cancer drugs and/or radiation therapy to the patient clinical response, if possible.
Time frame: 5 years
Plan to share: No — To protect participant privacy, individual patient-level data will not be shared. However, anonymized and de-identified data may be made available upon reasonable request, in accordance with applicable data protection regulations and institutional policies.
No publications or documents are linked to this record.
Started Mar 2026 (actual). Primary completion is estimated for Sep 2031, 66 months after the start.
Of 541 non-industry observational studies under Prostatic Neoplasms, half reached primary completion within 67 months of starting (the median), counting those still running; a quarter within 29 and three quarters within 162. This study's planned 66 months is close to that.
Counting every sponsor, half of 650 studies reached it within 60 months; a quarter within 29 and three quarters within 141.
How these figures are worked out, and which studies are left out of them.
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