A Study of MRI-guided High-dose Radiation Therapy in Prostate Cancer

One of the usual approaches to treating intermediate-risk prostate cancer is a type of radiation therapy called SBRT (stereotactic body radiation therapy). SBRT delivers higher than standard doses of radiation over a lower number of treatment sessions. However, there is a 20% chance that intermediate-risk prostate cancer will come back after this treatment. The purpose of this study is to find out whether giving an even higher dose (a "boost" dose) of radiation directly to the main tumor and the standard dose of radiation to the rest of the prostate may cure the cancer or prevent it from coming back for a longer period of time while causing few side effects.

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Key information

Conditions

Prostate Cancer Genital Diseases Genital Diseases, Male Genital Neoplasms, Male Male Urogenital Diseases Neoplasms Neoplasms by Site Prostatic Diseases Prostatic Neoplasms Urogenital Diseases Urogenital Neoplasms

Age range

18 year and older

Sex eligibility

Male

Study type

Interventional

Phase

Phase 2

Primary location

Memorial Sloan Kettering at Basking Ridge (Limited Protocol Activities), Basking Ridge, New Jersey, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Intermediate-risk prostate cancer patients will be eligible for this study. Risk groups will be assigned as per NCCN guidelines. Intermediate-risk patients will be defined as:

PSA 10-20 ng/ml or
Gleason score = 7 or
Clinical stage T2b/T2c or
Additionally, patients will be required to meet all of the following criteria:

Age ≥ 18
Karnofsky Performance Status (KPS) ≥ 80 (Appendix 1)
Prostate size ≤ 80 cc
Presence of a T2-visible prostatic lesion with maximum dimension of ≥ 0.5 cm and no more than one additional disease focus
MRI findings: Lesion may contact the capsular edge, possible extracapsular extension (ECE) permitted
International Prostate Symptom Score ≤ 15
Satisfy all MRI screening criteria and be willing to fill out the standard MRI screening form

Exclusion criteria

Patient will be excluded if they meet any one of the following criteria:

Gleason score >7
PSA >20
Prior or concurrent androgen deprivation therapy for prostate cancer MRI findings: suspicious for/probable ECE
MRI findings: >2 disease foci identifiable
Evidence of metastatic disease on bone scan or MRI/CT
MRI ineligibility due to: the presence of a cardiac pacemaker, defibrillator, or other implanted metallic or electronic device which is considered MR unsafe; severe claustrophobia; inability to lie flat for the duration of the study; etc.
Metallic implant or device in the pelvis that might distort the local magnetic field and compromise quality of mp-MRI
Lateral pelvic separation greater than 50 cm and/or anterior-posterior separation greater than 35 cm which are incompatible with MRCAT reconstruction
Contra-indications to receiving gadolinium contrast
KPS < 80
Pelvic or prostate MRI or CT (MRI preferred) evidence of radiographic T3, T4, or N1 disease
Prior history of transurethral resection of the prostate
Prior history of urethral stricture
Prior history of pelvic irradiation
History of inflammatory bowel disease
Unable to give informed consent
Unable to complete quality of life questionnaires
Abnormal complete blood count, including any of the following:

Platelet count less than 75,000/ml
Hb level less than 10 gm/dl
WBC less than 3.5/ml
Abnormal renal function tests (creatinine > 1.5)

Treatment and study plan

radiation therapy

Radiation

Patients enrolled in this study will undergo ultra-hypofractionated radiation utilizing MR guided, daily online adaptive planning. Patients will receive a standard dose of 8 Gy/fraction for five fractions for a total dose of 40 Gy to the prostate with a simultaneously-delivered boost of 9 Gy for five fractions (clinically non-standard dose of 45 Gy total) to a single dominant lesion with a maximum dimension of at least 0.5 cm, as determined on the pretreatment diagnostic T2 MRI imaging. In the setting of two similarly-sized "dominant" lesions, both will be boosted.

Other names: SBRT

Primary outcomes

Comparison of pretreatment biopsy with post-treatment biopsy

Time frame: 24 months

The primary outcome of efficacy will be studied using post -treatment biopsies. To demonstrate efficacy of dose escalation to the DIL, the investigators aim to reduce the positive post-treatment biopsy rates at 24 months for intermediate risk disease from 20% to 10%.

Sponsors and collaborators

Lead sponsor

Memorial Sloan Kettering Cancer Center

Other

Registry information

Official study title

A Phase II Study of Radiotherapy to the Prostate and Dose Intensification to the Dominant Intra- Prostatic Lesion (DIL) Using Ultra-Hypofractionated, MR-Guided Radiotherapy

Important dates

Study start: 2021
Primary completion: 2026
Study completion: 2026
First posted: Aug 9, 2021
Registry last updated: Jan 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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