Whole Versus Partial Gland Boost During Prostate SBRT

University of Nebraska

Status and phase: Not yet enrolling; Phase 3; Phase 2

Conditions: Prostate Adenocarcinoma; Prostate Cancer

Treatments: Radiation: Prostate stereotactic body radiotherapy with DIL boost; Radiation: Prostate stereotactic body radiotherapy with whole gland boost

Study type: Interventional

Funder types: Other

Identifiers

NCT07574489

Gland Boost

Details and patient eligibility

About

This phase 2/3 randomized trial evaluates whether dose escalation to the dominant intra-prostatic lesion (DIL) compared to whole gland dose escalation during prostate stereotactic body radiotherapy (SBRT) results in differences in genitourinary (GU) and gastrointestinal (GI) toxicities.

Full description

This is a phase 2/3 randomized clinical trial evaluating two dose escalation strategies during prostate stereotactic body radiotherapy (SBRT). A total of 186 patients with prostate adenocarcinoma will be enrolled and randomized in a 1:1 ratio to one of two treatment arms.

In both arms, patients will receive 3625 cGy delivered to the planning target volume (PTV) over 5 fractions. In Arm A, patients will receive a boost to the prostate gland. In Arm B, patients will receive a boost to the dominant intra-prostatic lesion (DIL) identified on pre-treatment magnetic resonance imaging (MRI).

The primary objective is to evaluate chronic genitourinary (GU) and gastrointestinal (GI) toxicities grade 2 or higher from 6 months to 2 years post-treatment using the Common Terminology Criteria for Adverse Events (CTCAE). Secondary objectives include evaluation of acute and chronic GU and GI toxicities using CTCAE, Radiation Therapy Oncology Group (RTOG), and Expanded Prostate Cancer Index Composite (EPIC) domains, as well as biochemical progression-free survival at 5 years.

Participants will be followed for up to 5 years after completion of treatment.

Enrollment: 186 estimated patients

Sex: Male

Ages: 19+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Adults ≥19 years of age
2. Patients with a diagnosis of prostate adenocarcinoma for which stereotactic body radiotherapy (SBRT) to the prostate ± proximal seminal vesicles is being offered
3. Prostate gland volume <100 cc prior to initiation of androgen deprivation therapy (ADT), as reported at time of biopsy or by imaging (e.g., ultrasound, MRI, or CT)
4. PI-RADS 4 or 5 lesion seen on pre-treatment MRI
5. IPSS/AUA symptom score less than 16

Exclusion criteria

1. Prior treatment for prostate cancer
2. Prior solid cancer diagnosis within the last 5 years
3. Any history of anal or rectal cancer
4. Any history of invasive carcinoma of the bladder
5. History of prior circumferential resection of the rectum (such as LAR or APR)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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186 participants in 2 patient groups

Arm A: boost to prostate alone

Active Comparator group

Description:

Participants assigned to Arm A will receive external beam radiation therapy consisting of 3625 cGy to the planning target volume (PTV), plus a boost of 4000 cGy to the clinical target volume (CTV), consisting of the prostate alone without a margin. Treatment will be delivered over 5 fractions with at least 36 hours between fractions via simultaneous integrated boost (SIB).

Treatment:

Radiation: Prostate stereotactic body radiotherapy with whole gland boost

Arm B: boost to dominant intra-prostatic lesion (DIL)

Experimental group

Description:

Participants assigned to Arm B will receive external beam radiation therapy consisting of 3625 cGy to the planning target volume (PTV), plus a boost of 4500 cGy to the dominant intra-prostatic lesion (DIL). Treatment will be delivered over 5 fractions with at least 36 hours between fractions via simultaneous integrated boost (SIB).

Treatment:

Radiation: Prostate stereotactic body radiotherapy with DIL boost