Focal Micro-boost Strategy in Patients With Intermediate- to High-risk Prostate Cancer (IR-HR PCa) Undergoing Hypofractionated Radiotherapy

NCT07792993 | Recruiting DMC

• 1 other identifier: RS383/IRE/25
• Study Type: observational
• Target: 82
• Locations: 1 country
• Sites: 1

Brief Summary

HYPO62 SPECIAL is a monocentric, prospective observational cohort study promoted by IFO-IRE/ISG, designed to evaluate a moderately hypofractionated radiotherapy strategy with focal micro-boost in patients with localized intermediate- or high-risk prostate cancer. Definitive radiotherapy is an established treatment option for localized prostate cancer. Over recent decades, technical advances such as 3D conformal radiotherapy, IMRT, and multiparametric MRI have enabled more precise dose delivery and better identification of dominant intraprostatic lesions. Since most local recurrences occur in the original tumor area, selective dose escalation to MRI-visible dominant lesions represents a rational strategy to improve biochemical control while limiting toxicity to surrounding organs at risk. The study is based on previous evidence, including FLAME and DELINEATE, showing that focal boosting of dominant intraprostatic lesions can improve biochemical outcomes without significantly increasing toxicity when organ-at-risk constraints are respected. At the Regina Elena National Cancer Institute, the standard moderately hypofractionated schedule consists of 62 Gy in 20 fractions to the prostate. In this protocol, visible dominant intraprostatic lesions receive a focal micro-boost up to 71.3 Gy, while seminal vesicles may receive 56 Gy according to clinical risk. The primary objective is to assess the oncological efficacy of this focal micro-boost strategy in terms of 3-year biochemical recurrence-free survival. Biochemical recurrence is defined according to the Phoenix criteria as PSA nadir plus 2 ng/mL or the start of salvage androgen deprivation therapy. Secondary and exploratory objectives include treatment-related toxicity assessed with CTCAE v5.0 at different timepoints, recurrence patterns, 3-year overall survival, and 3-year metastasis-free survival. Eligible patients are adults with histologically confirmed prostate adenocarcinoma, intermediate- or high-risk disease according to NCCN criteria, no regional or distant metastases, ECOG performance status 0-1, and at least one mpMRI-visible PI-RADS 4 or 5 lesion, or a PI-RADS 3 lesion confirmed by biopsy. All patients will provide written informed consent. Patients will be treated according to routine clinical practice with 20 fractions delivered five times per week. Treatment planning includes CT simulation and pre-treatment multiparametric MRI. The prostate, seminal vesicles when indicated, dominant lesions, and organs at risk will be contoured after CT-MRI registration. The planning target volume is generated from the clinical target volume with appropriate margins, while no additional margin is applied to the dominant intraprostatic lesion. Organ-at-risk constraints will take priority over full boost coverage. A total of 82 consecutive patients are planned for inclusion. This sample size is considered adequate to test whether the 3-year biochemical recurrence-free survival improves from 68% to 80%, with 80% probability and a one-sided 5% significance level. Statistical analyses will include Kaplan-Meier survival estimates, log-rank testing, and multivariable logistic and Cox regression models. The expected enrolment and data collection period is 36 months, with a minimum observational follow-up of 36 months and an estimated total study duration of 72 months.

Conditions

Localized Prostate Cancer

Keywords

moderately hypofractionated radiotherapy; simultaneous integrated boost; biochemical recurrence-free survival

Outcome Measures

Primary Outcomes (1)

• Assess the oncologic efficacy

  To assess the oncologic efficacy of a focal micro-boost strategy in patients with intermediate to highrisk prostate cancer (IR-HR PCa) undergoing hypofractionated radiotherapy, in terms of biochemical relapse free survival (bRFS) at 3 years.

  From the last day of radiotherapy treatment to 36 months after treatment completion.

Study Arms (1)

arm 1

The study population includes adult patients with histologically confirmed prostate adenocarcinoma who are eligible for moderately hypofractionated radiotherapy in 20 fractions and have at least one MRI-visible lesion suitable for focal boosting. Patients must have intermediate or high-risk prostate cancer according to NCCN risk stratification. Unfavourable intermediate-risk disease includes patients without high-risk features but with two or three intermediate-risk factors, Grade Group 3 disease and/or more than 50% positive biopsy cores. Intermediate-risk factors include clinical stage T2b-T2c, Grade Group 2-3 and PSA between 10 and 20 ng/mL. High-risk disease includes clinical stage T3a, Grade Group 4-5 or PSA greater than 20 ng/mL.

Eligibility Criteria

• Age: 18 Years - 99 Years
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population includes adult patients with histologically confirmed prostate adenocarcinoma who are eligible for moderately hypofractionated radiotherapy in 20 fractions and have at least one MRI-visible lesion suitable for focal boosting. Patients must have intermediate or high-risk prostate cancer according to NCCN risk stratification. Unfavourable intermediate-risk disease includes patients without high-risk features but with two or three intermediate-risk factors, Grade Group 3 disease and/or more than 50% positive biopsy cores. Intermediate-risk factors include clinical stage T2b-T2c, Grade Group 2-3 and PSA between 10 and 20 ng/mL. High-risk disease includes clinical stage T3a, Grade Group 4-5 or PSA greater than 20 ng/mL.

You may qualify if:

• Age 18 years or older.
• Histologically confirmed diagnosis of prostate adenocarcinoma.
• Intermediate or high-risk prostate cancer according to NCCN criteria.
• No regional or distant metastases.
• ECOG performance status 0-1.
• Eligibility for moderately hypofractionated radiotherapy in 20 fractions.
• Presence of at least one PI-RADS 4 or 5 lesion on multiparametric MRI, or a PI-RADS 3 lesion confirmed as positive at pathology.
• Ability to understand the Italian language and adhere to study procedures.
• Written informed consent for participation and data processing.

You may not qualify if:

• Previous local prostate treatment with radiotherapy, brachytherapy, cryosurgery, high-intensity focused ultrasound or cryotherapy.
• Previous pelvic radiotherapy.
• Presence of nodal or distant metastases confirmed by MRI or PET/CT.

Sponsors & Collaborators

• Regina Elena Cancer Institute: lead

Study Sites (1)

IRCCS Regina Elena National Cancer Institute

Rome, Lazio, 00144, Italy

RECRUITING

Related Publications (3)

• Tree AC, Satchwell L, Alexander E, Blasiak-Wal I, deSouza NM, Gao A, Greenlay E, McNair H, Parker C, Talbot J, Dearnaley D, Murray J. Standard and Hypofractionated Dose Escalation to Intraprostatic Tumor Nodules in Localized Prostate Cancer: 5-Year Efficacy and Toxicity in the DELINEATE Trial. Int J Radiat Oncol Biol Phys. 2023 Feb 1;115(2):305-316. doi: 10.1016/j.ijrobp.2022.09.058. Epub 2022 Sep 21.

  PMID: 36150450 BACKGROUND

• Kerkmeijer LGW, Groen VH, Pos FJ, Haustermans K, Monninkhof EM, Smeenk RJ, Kunze-Busch M, de Boer JCJ, van der Voort van Zijp J, van Vulpen M, Draulans C, van den Bergh L, Isebaert S, van der Heide UA. Focal Boost to the Intraprostatic Tumor in External Beam Radiotherapy for Patients With Localized Prostate Cancer: Results From the FLAME Randomized Phase III Trial. J Clin Oncol. 2021 Mar 1;39(7):787-796. doi: 10.1200/JCO.20.02873. Epub 2021 Jan 20.

  PMID: 33471548 BACKGROUND

• Menne Guricova K, Pos FJ, Schoots IG, Vogel WV, Kerkmeijer LGW, Monninkhof EM, de Boer JCJ, van der Voort van Zyp JRN, Kunze-Busch M, Smeenk RJ, Draulans C, Haustermans K, van Houdt PJ, van der Heide UA. Intra-prostatic recurrences after radiotherapy with focal boost: Location and dose mapping in the FLAME trial. Radiother Oncol. 2024 Dec;201:110535. doi: 10.1016/j.radonc.2024.110535. Epub 2024 Sep 13.

  PMID: 39278316 BACKGROUND

Central Study Contacts

Giuseppe Sanguineti, MD

CONTACT

Italy: +39 0652665031; giuseppe.sanguineti@ifo.it

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 36 Months
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: August 25, 2026
• First Posted: August 28, 2026
• Study Start: August 7, 2025
• Primary Completion (Estimated): December 30, 2027
• Study Completion (Estimated): June 30, 2028
• Last Updated: August 28, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)