Prostate Oncologic Therapy While Ensuring Neurovascular Conservation (POTEN-C)

NCT03525262 | Active Not Recruiting Phase 2 DMC

• 1 other identifier: STU 092017-018
• Study Type: interventional
• Target: 124
• Locations: 1 country
• Sites: 8

Brief Summary

Reduction of dose to or 'sparing' of neurovascular structures during stereotactic ablative body radiotherapy (SAbR) for localized prostate cancer will improve retention of sexual potency, while retaining excellent oncologic control and other secondary health-related quality of life (HRQOL) endpoints. Primary Objectives:

• To compare the decline in patient health-related quality of life (HRQOL) instrument-defined erectile dysfunction following stereotactic ablative body radiotherapy (SAbR) with or without neurovascular sparing Secondary Objectives:
• Assess acute (within 3 months of treatment) and chronic (\>3 months after treatment) SAbR related GU and GI toxicities, as well as serial impact on HRQOL metrics over time
• Assess biochemical progression free survival, local recurrence, distant recurrence, and survival
• Evaluate simplified 'practical' secondary HRQOL sexual potency endpoints that can be compared to prior literature. Exploratory Objectives:
• Evaluate feasibility of MRI BOLD/TOLD to be integrated as hypoxia monitoring sequences to standard already planned diagnostic and/or treatment planning MRI on the study in five patient pilot.
• Evaluate quality of spacer placement and its effect on dose to neurovascular structures
• Evaluate rate local recurrence in the area of sparing adjacent to the neurovascular elements by biopsy in those with biochemical progression.

Conditions

Prostate Cancer Adenocarcinoma

Keywords

Erectile dysfunction, Neurovascular, Prostate, Rectal spacer, Radiotherapy

Outcome Measures

Primary Outcomes (1)

• To compare the decline in patient health-related quality of life.

  To compare the decline in patient health-related quality of life (HRQOL) instrument-defined erectile dysfunction following stereotactic ablative body radiotherapy (SAbR) with or without neurovascular sparing. The Expanded Prostate Cancer Index Composite (EPIC) health-related quality of life (HRQOL) instrument includes four sub-scales like urinary function, bowel habits, sexual function, and hormonal function. The primary outcome (sexual function) which has a range score of 0-100 from 9 questions related to ability to achieve an erection with or without aids and participate in intercourse. Higher the score represents the better outcome. Individual responses are summed for a total score of sexual function.

  Mean 24-Months

Secondary Outcomes (6)

• Acute & Chronic Genitourinary (GU) and Gastrointestinal (GI) toxicity

  Mean 24-Months

• Biochemical progression free survival.

  60 Months

• Time to local recurrence.

  60 Months

• Time to distant recurrence.

  60 Months

• Overall survival.

  60 Months

Study Arms (2)

SAbR WITHOUT Neurovascular sparing

NO INTERVENTION

* GTV represents MR defined dominant radiographic disease, if identifiable. * CTV encompasses the full prostate. At physician's discretion, the insertion of the seminal vesicle upon the prostate on slices containing prostate may be included. * PTV1\_30Gy will not be used or created on this arm * PTV2\_SAbR40Gy OR PTV2\_SAbR45Gy will be generated by a 3mm expansion on the CTV. PTV2\_SAbR will receive 8-9 Gy per fraction for 5 fractions (40-45 Gy).

SAbR WITH Neurovascular sparing

EXPERIMENTAL

* GTV represents MR defined dominant radiographic disease, if identifiable. * CTV encompasses the full prostate. At physician's discretion, the insertion of the seminal vesicle upon the prostate on slices containing prostate may be included. * PTV1\_30Gy represents a 3mm expansion on the CTV, excluding the neurovascular structures on the side to be spared (left or right). PTV1 will receive 6 Gy per fraction for 5 fractions (30 Gy). * PTV2\_SAbR40Gy OR PTV2\_SAbR45Gy will be generated by subtracting a 5mm expansion around the neurovascular elements to be spared (at least one side, left or right) from PTV1. These neurovascular structures consist of the neurovascular bundle, penile bulb, and internal pudendal arteries (see 4.1.5.2.16). PTV2 will receive 8-9 Gy per fraction for 5 fractions (40-45 Gy).

Radiation: 30Gy (Gray) planning target volume (PTV)

Interventions

30Gy (Gray) planning target volume (PTV) RADIATION

PTV1\_30Gy represents a 3mm expansion on the prostate (and proximal seminal vesicle per physician discretion), excluding the neurovascular structures on the side to be spared (left or right). PTV1 will receive 6 Gy per fraction for 5 fractions (30 Gy).

SAbR WITH Neurovascular sparing

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 18 years.
• Appropriate staging studies identifying patient as AJCC 7th edition clinical stage T1 (a, b, or c) or T2 (a, b, or c) adenocarcinoma of the prostate gland. The patient should not have direct evidence of regional or distant metastases after appropriate staging studies. See Appendix I for details on AJCC 7th Edition staging criteria. Histologic confirmation of cancer will be required by biopsy performed within 12 months of registration. T-staging may be assessed by multi-parametric imaging alone if digital rectal examination was deferred.
• The patient's Zubrod performance status must be 0-2 (see Appendix II for definition).
• The Gleason summary score should be less than or equal to 7 \[Grade group 1 (Gleason 3+3=6), group 2 (Gleason 3+4=7), and group 3 (Gleason 4+3=7) are allowed\]. See Appendix III for details on definitions. While a template biopsy is recommended, it is not required in the case of MRI fusion biopsy performed on all dominant MR lesions (defined as PIRADS v2 4-5).
• Baseline AUA symptom score ≤19 (see Appendix IV for questionnaire) without need for maximum medical therapy (specifically, not on tamsulosin 0.8mg daily).
• EPIC sexual domain composite score 60-100 (see Appendix V).
• Multi-parametric MRI evaluation of the prostate is required for this study within 12 months of registration. Gross radiographic disease on MRI (defined as PIRADS v2 score 3-5) must be \> 5mm at minimum distance from at least one side's neurovascular bundle, which is typically the closest of the neurovascular elements to the prostate.
• The serum PSA should be less than or equal to 20 ng/ml within 90 days of registration.
• Study entry PSA must not be obtained during the following time frames: (1) 10-day period following prostate biopsy; (2) following initiation of ADT or anti-androgen therapy; (3) within 30 days after discontinuation of finasteride; (4) within 90 days after discontinuation of dutasteride; (5) within 5 days of a digital rectal examination (which is not a required exam on the protocol).
• Ultrasound or MRI based volume estimation of prostate gland ≤ 80 grams. Cytoreduction therapy (finasteride or dutasteride only) may be considered for those with \>60 gram size.
• All patients must be willing and capable to provide informed consent to participate in the protocol within the 30 days prior to registration.

You may not qualify if:

• Subjects with clinical (digital rectal examination) evidence of extraprostatic extension (T3a) or seminal vesicle involvement (T3b). MRI evidence of equivocal/potential but not definite extraprostatic extension is allowed, as long as it is unilateral and not on the side of the gland proposed for neurovascular element sparing. In equivocal cases of potential extracapsular extension on MRI only, discretion is left to the treating physician.
• MRI evidence of gross disease (defined as PIRADS v2 score 3-5 lesions) ≤5mm of BOTH neurovascular bundles, which are the most proximate of the neurovascular elements planned for sparing on this protocol.
• Patients with all three intermediate risk factors (PSA \>10 and ≤ 20, Gleason 7, clinical stage T2b-T2c) who ALSO have ≥50% of the number of their template biopsy cores positive for cancer are ineligible.
• Inability to undergo multi-parametric MRI.
• Evidence of metastatic disease. Note bone scan is not required for this study given the low-intermediate NCCN risk cohort to be enrolled.
• Evidence of clinical nodal involvement of the pelvis. Biopsy is required for lymph nodes over ≥1.5cm in short-axis measured size.
• No currently active ADT or anti-androgen therapy at time of registration is allowed. Further, no more than 3 cumulative months of prior ADT or anti-androgen therapy is allowed. If either has been used by the patient, there must be a demonstration of testosterone recovery (\>50ng/dL serum blood level), EPIC sexual domain score ≥60, and at least 1 month between demonstration of testosterone recovery and study registration (any one measurement of testosterone recovery suffices).
• Subjects who have had previous pelvic radiotherapy or have had chemotherapy or surgery for prostate cancer.
• Subjects who have plans to receive other concomitant or post treatment adjuvant antineoplastic therapy while on this protocol including surgery, cryotherapy, conventionally fractionated radiotherapy, hormonal therapy, or chemotherapy given as part of the treatment of prostate cancer.
• Subjects who have undergone previous transurethral resection of the prostate (TURP) within 1 year of enrollment or ablative procedures to the prostate for benign prostatic hyperplasia or other conditions (i.e. cryotherapy, HIFU).
• Subjects who have baseline severe urinary symptoms, as defined by AUA symptom score \>19 (alpha-blocker medication allowed except if taking tamsulosin 0.8mg daily at baseline which indicates compensated severe symptoms and also can affect sexual function).
• Subjects who have a history of significant psychiatric illness that would confound informed consent.
• Severe, active co-morbidity, defined as follows:
• Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months
• Myocardial infarction within the last 6 months

Sponsors & Collaborators

• University of Texas Southwestern Medical Center: lead
• Boston Scientific Corporation: collaborator

Study Sites (8)

UCSF ( Department of Radiation Oncology University of California San Francisco)

San Francisco, California, 94143, United States

Location

University of Colorado Hospital

Aurora, Colorado, 80045, United States

Location

Penrose Hospital

Colorado Springs, Colorado, 80907, United States

Location

University of Michigan- Michigan Medicine

Ann Arbor, Michigan, 48109, United States

Location

Stony Brook University Cancer Center

Stony Brook, New York, 11794, United States

Location

Cleveland Clinic

Cleveland, Ohio, 44195, United States

Location

Penn Medicine Radiation Oncology

Philadelphia, Pennsylvania, 19104, United States

Location

UT Southwestern Cancer Center

Dallas, Texas, 75235, United States

Location

MeSH Terms

Conditions

Erectile Dysfunction

Condition Hierarchy (Ancestors)

Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Sexual Dysfunction, Physiological; Male Urogenital Diseases; Sexual Dysfunctions, Psychological; Mental Disorders

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor of Medicine

Study Record Dates

• First Submitted: April 23, 2018
• First Posted: May 15, 2018
• Study Start: April 24, 2018
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2029
• Last Updated: June 4, 2025

Record last verified: 2025-05

Locations

US (8)