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Online Adaptive Stereotactic Body Radiotherapy for Localized Prostate Cancer

Online Adaptive Stereotactic Body Radiotherapy for Localized Prostate Cancer in Patients With Lower Urinary Tract Symptoms and/or Prostate Hyperplasia (X-SMILE)

Status
Recruiting
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT06834152
Acronym
X-SMILE
Enrollment
75
Registered
2025-02-19
Start date
2024-03-01
Completion date
2031-06-30
Last updated
2026-07-06

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Localized Prostate Carcinoma, Lower Urinary Track Symptoms, Prostate Cancer (Adenocarcinoma), Prostate Hyperplasia

Keywords

radiotherapy, SBRT, MRI, CT, stereotactic radiotherapy, localized prostate cancer, lower urinary tract symptoms, prostate hyperplasia, prostate cancer

Brief summary

The aim of this phase II international multicenter study is to evaluate the safety, feasibility, and efficacy of CT or MRI-adaptive SBRT, delivered in five weekly fractions, in patients with newly diagnosed localized prostate cancer who have lower urinary tract symptoms and/or prostatic hyperplasia.

Detailed description

Background: Stereotactic body radiotherapy (SBRT) for localized prostate cancer has demonstrated non-inferior oncological outcomes and toxicity profiles to conventionally or moderately hypofractioned radiotherapy regimens, while offering the advantage of shorter treatment durations. However, SBRT may not be suitable for all patients, particularly those with lower urogenital tract symptoms and/or prostatic hyperplasia. Methods: This study aims to evaluate the safety and efficacy of weekly computed tomography (CT) or magnetic resonance image-guided (MRI) online adaptive SBRT in patients with intermediate to (very) high-risk localized prostate cancer who present with lower urinary tract symptoms (International Prostate Symptom Score \[IPSS\] \> 12) and/or have prostate hyperplasia (prostate volume \>60 mL). The primary outcome measure is urogenital toxicity grade ≥3 within 3 months after completion of SBRT (according to CTCAE V5.0 and RTOG) or discontinuation of therapy. Our aim is to show that the event rate is at 3% below a clinically acceptable threshold, which is set at 20%. Under the null hypothesis, this design with an alpha of 0.05 and power of 80% results in an expected number of cases of 30. In our validation cohort we assume that around 3% of patients will have grade 3 long-term urogenital toxicity (i.e. 2 patients). The rate of treatment discontinuation within 3 months is considered negligible. Our aim is to show with high probability, that the event rate is below a clinically acceptable threshold, which is set at 12%. Under the null hypothesis, this design with an alpha of 0.05 and power of 80% results in an expected number of cases of 75.

Interventions

RADIATIONradiotherapy

Patients with prostate cancer in the medium or high risk range who are planned to receive definitive CT or MRI-adaptive SBRT.

Sponsors

University of Zurich
Lead SponsorOTHER

Study design

Observational model
CASE_ONLY
Time perspective
PROSPECTIVE

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* histologically confirmed localized prostate cancer * planned treatment is SBRT according to standard of care and consists of definitive CT or MRI online adaptive SBRT of the prostate according to the PACE trial which includes a total dose to clinical target volume 1 (CTV1, i.e. prostate and proximal 1 cm of the seminal vesicle) of 40.0 Gy in 5 weekly fractions (single dose of 8.0 Gy) and total dose to planning target volume 1 (PTV1) of 37.5 Gy in 5 weekly fractions (single dose of 7.5 Gy) with a compromise for bowel sparing allowed. For patients with unfavorable intermediate to very high-risk disease (according to NCCN guidelines) a total dose to the planning target volume 2 (PTV2, i.e. proximal 1-2 cm of the seminal vesicle) of 32.5 Gy in 5 weekly fractions (single dose of 6.5 Gy) will be delivered. * intermediate to (very) high risk localized prostate cancer (≤ cT3a and Gleason score ≤ 9 and/or PSA ≤ 20 ng/ml) * prostate volume \> 60 cc and/or IPSS \> 12;

Exclusion criteria

* Very high risk localized prostate cancer with indication for ADT and ARPI (i.e. Gleason ≥ 8 and cT3a) * Involvement of seminal vesicles (cT3b) * Contraindications against definitive CT or MRI-adaptive radiotherapy of the prostate, e.g. inflammatory bowel disease (IBD); previous radiotherapy in the pelvis, previous local radiotherapy of the prostate, contraindication for MRI or CT; * Patients with severe genitourinary symptoms (e.g. recent urinary retention ≥ grade 3 according CTCAE v.5.0); * Lymph node metastases or distant metastases (i.e. no localised prostate cancer); * Participation in a clinical trial which might influence the results of this project.

Design outcomes

Primary

MeasureTime frameDescription
acute grade ≥ III urogenital toxicity≤ 3 months after completion of radiotherapyThe primary endpoint is acute grade ≥ III urogenital toxicity ≤3 months after completion of radiotherapy (according to the NCI CTCAE V5 or RTOG) or treatment discontinuation related to treatment.

Secondary

MeasureTime frameDescription
Gastrointestinal toxicity of grade ≥3≤ 3 months after completion of radiotherapyGastrointestinal toxicity of grade ≥3 within 3 months after completion of radiotherapy (according to CTCAE V5.0 and RTOG)
Mortality≤1 year after initiation of radiotherapyMortality (related to treatment and/or disease).
Urogenital and gastrointestinal toxicities≤ 5 years after completion of radiotherapyNumber of urogenital and gastrointestinal toxicities within 5 years after completion of radiotherapy and their severity.
Biochemical progression-free survival≤ 5 years after completion of radiotherapyBiochemical progression-free survival (determined from the start of therapy until the occurrence of PSA recurrence according to the Phoenix criteria i.e. post- therapeutic PSA nadir + 2 ng/ml),
Hormonal therapy-free survival≤ 5 years after completion of radiotherapyHormonal therapy-free survival (determined from the start of therapy until the start of hormonal therapy,
Overall survival5 years after completion of radiotherapyoverall survival (defined from the start of therapy until death or censoring)
Quality-of-life questionnaire C-30 from the European Organisation for Research and Treatment of Cancer≤ 5 years after completion of radiotherapyQuality-of-life measured using the EORTC QLQ-C30 questionnaire during and after treatment All of the scales and single-item measures range in score from 0 to 100. A high scale score represents a higher response level. Thus a high score for a functional scale represents a high/healthy level of functioning, a high score for the global health status/QoL represents a high QoL, but a high score for a symptom scale/item represents a high level of symptomatology/problems.
Uroflowmetry (optional)Uroflowmetry ≤ 6 weeks prior to the start of radiotherapyUroflowmetry prior to the start of radiotherapy (optional study procedure)
Quality-of-life questionnaire PR25 of the European Organisation for Research and Treatment of Cancer≤ 5 years after completion of radiotherapyQuality-of-life measured using the QLQ-PR25 questionnaire during and after treatment All of the scales and single-item measures range in score from 0 to 100. A high score for the Sexual Activity and Sexual Functioning scales represents a high level of functioning, whereas a high score for the Urinary, Bowel, and Hormonal Treatment-Related symptoms scales and Incontinence Aid item represents a high level of symptomatology or problems.

Countries

Germany, Switzerland

Contacts

CONTACTRadiation Oncology Study Office
RAO_akademischesoffice@usz.ch+41442554108
STUDY_CHAIRMatthias Guckenberger, Prof. Dr. med.

University of Zurich

PRINCIPAL_INVESTIGATORTiuri E. Kroese, MD, PhD

University of Zurich

PRINCIPAL_INVESTIGATORMatthias Guckenberger

University of Zurich

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jul 7, 2026