Is Adaptive SBRT for Prostate vs Image-guided Radiotherapy a True Evolution (ASPIRE) (ASPIRE)

The ASPIRE study is a Phase III randomized, single-center study designed to evaluate whether adaptive stereotactic body radiotherapy (SBRT) offers superior clinical benefits compared to standard image-guided SBRT for patients with localized prostate cancer. It aims to explore whether adaptive SBRT can improve urinary outcomes while maintaining effective cancer control.

This interventional study is randomized, single-institution, and includes 320 participants with localized prostate cancer. Patients will be stratified based on fractionation schedules (5 vs. 7 fractions), use of rectal spacers, androgen deprivation therapy (ADT), and baseline alpha receptor antagonist use. Participants will be randomized to receive either adaptive SBRT or standard image-guided SBRT, with both arms adhering to established dosing protocols.

Inclusion criteria includes an age greater than 18 years, diagnosed with localized prostate adenocarcinoma, and an ECOG performance status of 0-1, Eligible for prostate SBRT. The exclusion criteria includes patients who plan for elective nodal irradiation and contraindications to radiotherapy or MRI (for MR-Linac patients).

Study Overview

• Status: Recruiting
• Conditions: Stereotactic Body Radiotherapy; Localized Prostate Cancer
• Intervention / Treatment: Radiation: SBRT

• Study Type: Interventional
• Enrollment (Estimated): 320
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Rachel Glicksman, MD; Phone Number: 4961 416-946-4559; Email: rachel.glicksman@uhn.ca

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G 2M9
      • Recruiting
      • Princess Margaret Cancer Center
      • Contact: Rachel Glicksman, MD; Phone Number: 4961 416-946-4559; Email: rachel.glicksman@uhn.ca

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age >18 years
2. Histologic diagnosis of prostate adenocarcinoma
3. Localized prostate cancer
4. Low risk, intermediate risk, or high risk allowed
5. Patient planned for prostate SBRT

Exclusion Criteria:

1. Planned for elective nodal irradiation
2. Contraindications to radiotherapy
3. Patients with bilateral hip replacements, as they are ineligible for adaptive treatments at present time (either MR-guided or CT-guided)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Non-adaptive image-guided SBRT; Patients will receive prostate SBRT. A dose of either 36.25 Gy in 5 fractions (per PACE-B trial) or 42.7 Gy in 7 fractions (per HYPO-RT-PC trial) will be prescribed as per standard practice at PMH. Patients will receive SBRT every other day, excluding weekends and holidays, as per standard practice. Patients will undergo radiotherapy simulation as per standard practice with CT and MR simulation (or without MR if contraindication).	Radiation: SBRT; Standard of care SBRT (36.25 Gy in 5 fractions or 42.7 Gy in 7 fractions) for localized prostate cancer, delivered either via an adaptive or a non-adaptive image-guided treatment. Androgen deprivation therapy use and duration is at the discretion of the treating physician and patient, in accordance with standard practice based on patients' prostate cancer risk group.
Other: Adaptive SBRT; Patients will receive prostate SBRT. A dose of either 36.25 Gy in 5 fractions (per PACE-B trial) or 42.7 Gy in 7 fractions (per HYPO-RT-PC trial) will be prescribed as per standard practice. Patients will receive SBRT every other day, excluding weekends and holidays, as per standard practice. Patients will undergo radiotherapy simulation as per standard practice with CT and MR simulation (or without MR if contraindication).	Radiation: SBRT; Standard of care SBRT (36.25 Gy in 5 fractions or 42.7 Gy in 7 fractions) for localized prostate cancer, delivered either via an adaptive or a non-adaptive image-guided treatment. Androgen deprivation therapy use and duration is at the discretion of the treating physician and patient, in accordance with standard practice based on patients' prostate cancer risk group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To determine whether adaptive SBRT can significantly reduce the proportion of patients experiencing a minimal clinically important difference in patient reported urinary domain changes when compared to the non adaptive image guided SBRT group.	To determine whether adaptive SBRT can significantly reduce the proportion of patients experiencing a minimal clinically important difference (MCID; defined as >10-point change) in patient reported urinary domain changes by EPIC-26 (The Expanded Prostate Cancer Index Composite) questionnaire. within 3-months following radiation when compared to the non-adaptive image guided SBRT group	Within 3 months following radiation therapy

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different rates of patient reported outcomes, acute toxicity.	Patient reported bowel via EPIC-26 (The Expanded Prostate Cancer Index Composite) questionnaire.	Within 3 months of radiation therapy
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different rates of patient reported outcomes, acute toxicity.	Patient reported sexual outcomes via EPIC -26 (The Expanded Prostate Cancer Index Composite) questionnaire.	Within 3 months of radiation therapy
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different rates of patient reported outcomes, acute toxicity.	Patient reported urinary outcomes via EPIC-26 (The Expanded Prostate Cancer Index Composite) questionnaire.	Within 3 months of radiation therapy
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different rates of patient- reported outcomes, acute toxicity.	Patient reported urinary outcomes via I-PSS (International Prostate Symptom Score).	Within 3 months of radiation therapy
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different rates of patient- reported outcomes at 2 years, late toxicity.	Patient reported bowel, sexual, and urinary outcomes via EPIC-26 (The Expanded Prostate Cancer Index Composite) at 2 years.	2 years following radiation.
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different rates of patient- reported outcomes at 2 years, late toxicity.	Patient reported urinary outcomes via I-PSS (International Prostate Symptom Score) questionnaire at 2 years.	2 years following radiation
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different cumulative incidence of biochemical failure and distant metastases.	Determine the acute toxicity at 3 months via CTCAE v5.0 (Common Terminology Criteria for Adverse Events).	Within 3 months of radiation therapy
To determine whether adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate results in different cumulative incidence of biochemical failure and distant metastases.	To determine the late toxicity at 2 years via the CTCAE v5.0 (Common Terminology Criteria for Adverse Events).	2 years following radiation
To determine the economic impact of adaptive SBRT to prostate compared to non adaptive image guided SBRT to prostate.	The cumulative incidence of biochemical failure and distant metastases, economic impact.	2 years following radiation

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
To determine the impact of magnetic resonance-based adaptive SBRT (e.g., MR-Linac) versus CT-based adapted SBRT (e.g., Ethos) across each of the primary and secondary objectives.	MR-based vs CT-based adaptive SBRT across each of the primary and secondary endpoints.	within 2 years following radiation
Tertiary endpoints: To determine whether cumulative dosimetric differences between adaptive and non adaptive prostate SBRT correlate with each of the primary and secondary objectives.	Adaptive vs non-adaptive target and organ-at-risk dosimetric differences.	within 2 years following radiation

Collaborators and Investigators

• Sponsor: University Health Network, Toronto

Study record dates

Study Major Dates

• Study Start (Actual): February 4, 2025
• Primary Completion (Estimated): February 4, 2030
• Study Completion (Estimated): February 4, 2030

Study Registration Dates

• First Submitted: January 26, 2025
• First Submitted That Met QC Criteria: February 7, 2025
• First Posted (Actual): February 13, 2025

Study Record Updates

• Last Update Posted (Actual): June 2, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms
• Other Study ID Numbers: 24-5757

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No