PRIAPUS-PCa Study: Stereotactic Body Radiation Therapy (SBRT) and Androgen Deprivation Therapy (ADT) Impact on Sexual Function on Men With Unfavorable Intermediate Risk Prostate Cancer (PRIAPUS-PCa)

A Single Arm Prospective Study to Investigate the Impact of Stereotactic Body Radiation Therapy (SBRT) and Androgen Deprivation Therapy (ADT) on Sexual Dysfunction in Unfavorable Intermediate Risk Prostate Cancer

This study looks at how combined radiation and hormone therapy affects sexual function in men with a specific type of prostate cancer, before and after treatment.

Study Overview

• Status: Not yet recruiting
• Conditions: Prostate Cancer (Adenocarcinoma); Sexual Dysfunction Male; Erectile Abnormalities
• Intervention / Treatment: Combination product: SBRT combined with ADT

Detailed Description

This study examines how two standard combination treatment for prostate cancer - a highly targeted form of radiation called Stereotactic Body Radiation Therapy (SBRT) and a hormone-blocking treatment called Androgen Deprivation Therapy (ADT) - impact sexual function in men with unfavorable intermediate risk prostate cancer. Participants will complete study questionnaires before treatment or Baseline, and after treatment, on Month 3, 9, 15, and 24.

• Study Type: Observational
• Enrollment (Estimated): 130

Contacts and Locations

• Study Contact: Name: Zoe Ignacio, RN, BN (BScN); Phone Number: 1-204-787-2955; Email: ccmb_manitoba_prostate_centre_research@cancercare.mb.ca

Study Locations

• Canada
  • Manitoba
    • Winnipeg, Manitoba, Canada, R3E 0V9
      • Manitoba Prostate Centre
      • Contact: Zoe Ignacio, RN, BN (BScN); Phone Number: 1-204-787-2955; Email: ccmb_manitoba_prostate_centre_research@cancercare.mb.ca
      • Principal Investigator: Vibhay Pareek, MD, FRCPC

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Favorable and unfavorable intermediate risk prostate cancer patients

Description

Inclusion Criteria:

• Men aged 18-80 years with biopsy-proven UIR-PCa (National Comprehensive Cancer Network [NCCN] criteria: Gleason score 7 (4+3), PSA 10-20 ng/mL, or clinical stage T2b-T2c)
• Planned treatment with SBRT (36.25-37.5 Gy in 5 fractions) and ADT (6 months)
• Baseline sexual function assessment available (International Index of Erectile Function [IIEF-5, also known as SHIM] score ≥ 12 or pre-selection erection status score of 1-3: erection insufficient for intercourse, sufficient but not optimal, or normal)
• Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
• Written informed consent to participate.

Exclusion Criteria:

• Prior pelvic radiotherapy, prostate surgery, ADT, or chemotherapy
• Pre-existing severe sexual dysfunction (IIEF-5 score < 12 or pre-selection erection status score of 0: no erection)
• Hypogonadism at presentation (baseline testosterone below normal range)
• Contraindications to SBRT or ADT
• Metastatic disease, second malignancy, or previous malignancies.
• Benign or malignant penile diseases.
• Use of medications altering ejaculation (e.g., 5-alpha reductase inhibitors)
• Psychiatric conditions affecting questionnaire completion or QoL assessment
• Severe comorbidities affecting QoL assessments (e.g., advanced cardiovascular disease).

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Observational; Prostate cancer patients receiving SBRT and ADT	Combination product: SBRT combined with ADT; SBRT combined with Zoladex

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in erectile dysfunction severity from baseline to 24 months, as measured by the change in International Index of Erectile Function 5-item version (IIEF-5) score.	Outcome Measure Title: Change in Erectile Function Score as Measured by the International Index of Erectile Function-5 (IIEF-5 / SHIM) Measurement Tool: International Index of Erectile Function-5 (IIEF-5, also known as SHIM) Unit of Measure: Total IIEF-5 score (range 1-25; higher scores indicate better erectile function) Derived Unit: Change in IIEF-5 score from baseline to 24 months (continuous variable, points)	Baseline, 3, 9, 15, and 24 months post-SBRT

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of patients with clinically significant (moderate to severe) erectile dysfunction	Measurement Tool: IIEF-5 (SHIM) Unit of Measure: Percentage (%) of patients with IIEF-5 score ≤ 11	Baseline, 3, 9, 15, and 24 months
Change in sexual function, as measured by the Expanded Prostate Cancer Index Composite 26-item version (EPIC-26) sexual domain score	Measurement Tool: EPIC-26 Questionnaire - Sexual Domain Unit of Measure: Standardized domain score (0-100 scale; higher scores indicate better sexual function)	Baseline, 3, 9, 15, and 24 months
Hormonal Domain Score of the Expanded Prostate Cancer Index Composite (EPIC-26)	Measurement Tool: EPIC-26 Questionnaire - Hormonal Domain Unit of Measure: Standardized domain score (0-100 scale; higher scores indicate better hormonal function)	Baseline, 3, 9, 15, and 24 months
Ejaculatory Function Score as Measured by the Male Sexual Health Questionnaire - Ejaculation Scale (MSHQ-ES-8)	Measurement Tool: Male Sexual Health Questionnaire - Ejaculation Scale (ES-8) Unit of Measure: Total ES-8 score (range 3-40; higher scores indicate worse ejaculatory function)	Baseline, 3, 9, 15, and 24 months
Health-Related Quality of Life Score as Measured by EORTC QLQ-ELD14	Measurement Tool: European Organization for Research and Treatment of Cancer Quality of Life Questionnaire - Elderly Module (EORTC QLQ-ELD14) Unit of Measure: Standardized subscale scores (0-100 scale): Functional scales (higher = better functioning) Symptom scales (higher = greater symptom burden)	Baseline, 3, 9, 15, and 24 months (for patients >70 years)

Collaborators and Investigators

• Sponsor: CancerCare Manitoba
• Collaborators: TerSera Therapeutics LLC

Publications and helpful links

General Publications

• Vickers AJ, Elkin EB. Decision curve analysis: a novel method for evaluating prediction models. Med Decis Making 2006;26:565. https://doi.org/10.1177/0272989X06295361.
• Balachandran VP, others. Nomograms in oncology: more than meets the eye. Lancet Oncol 2006;2015:e173-80. https://doi.org/10.1016/S1470-2045(14)71116-7.
• Kennady EH, Bryk DJ, Ali MM, Ratcliffe SJ, Mallawaarachchi I V, Ostad BJ, et al. Low-intensity shockwave therapy improves baseline erectile function: a randomized sham-controlled crossover trial. Sex Med 2023;11:1-5. https://doi.org/10.1093/sexmed/qfad053.
• Skolarus TA, Dunn RL, Sanda MG, Chang P, Greenfield TK, Litwin MS, et al. Minimally important difference for the expanded prostate cancer index composite short form. Urology 2015;85:101-6. https://doi.org/10.1016/j.urology.2014.08.044.
• Laviana AA, Hernandez A, Huang LC, Zhao Z, Koyama T, Conwill R, et al. Interpretation of Domain Scores on the EPIC-How Does the Domain Score Translate into Functional Outcomes? J Urol 2019;202:1150-8. https://doi.org/10.1097/JU.0000000000000392.
• Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)-A metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform 2009;42:377-81. https://doi.org/10.1016/j.jbi.2008.08.010.
• Alayed Y, Davidson M, Quon H, Cheung P, Chu W, Chung HT, et al. Dosimetric predictors of toxicity and quality of life following prostate stereotactic ablative radiotherapy. Radiother Oncol 2020;144:135-40. https://doi.org/10.1016/j.radonc.2019.11.017.
• Matsushima M, Kikuchi E, Matsumoto K, Kosaka T, Mizuno R, Ohashi T, et al. Erectile function status is highly associated with prostate-specific antigen bounce in localized prostate cancer patients treated with permanent prostate brachytherapy. Int J Urol 2016;23:247-52. https://doi.org/10.1111/iju.13029.
• Alemozaffar M, Regan MM, Cooperberg MR, Wei JT, Michalski JM, Sandler HM, et al. Prediction of Erectile Function Following Treatment for Prostate Cancer. JAMA 2011;306:1205-14. https://doi.org/10.1001/jama.2011.1333.
• Wheelwright S, Darlington AS, Fitzsimmons D, Fayers P, Arraras JI, Bonnetain F, et al. International validation of the EORTC QLQ-ELD14 questionnaire for assessment of health-related quality of life elderly patients with cancer. Br J Cancer 2013;109:852-8. https://doi.org/10.1038/bjc.2013.407.
• Sholklapper T, Creswell M, Cantalino J, Markel M, Zwart A, Danner M, et al. Ejaculatory Function Following Stereotactic Body Radiation Therapy for Prostate Cancer. J Sex Med 2022;19:771-80. https://doi.org/10.1016/j.jsxm.2022.02.018.
• Ramanathan R, Mulhall J, Rao S, Leung R, Martinez Salamanca JI, Mandhani A, et al. Predictive correlation between the international index of erectile function (IIEF) and sexual health inventory for men (SHIM): Implications for calculating a derived SHIM for clinical use. J Sex Med 2007;4:1336-44. https://doi.org/10.1111/j.1743-6109.2007.00576.x.
• Santana MJ, Feeny D, Johnson JA, McAlister FA, Kim D, Weinkauf J, et al. Assessing the use of health-related quality of life measures in the routine clinical care of lung-transplant patients. Qual Life Res 2010;19:371-9. https://doi.org/10.1007/s11136-010-9599-3.
• Detmar SB, Muller MJ, Schornagel JH, Wever LDV, Aaronson NK. Health-related quality-of-life assessments and patient-physician communication: A randomized controlled trial. Jama 2002;288:3027-34. https://doi.org/10.1001/jama.288.23.3027.
• Ray ME, Thames HD, Levy LB, Horwitz EM, Kupelian PA, Martinez AA, et al. PSA nadir predicts biochemical and distant failures after external beam radiotherapy for prostate cancer: A multi-institutional analysis. Int J Radiat Oncol Biol Phys 2006;64:1140-50. https://doi.org/10.1016/j.ijrobp.2005.07.006.
• Dixon SC, Knopf KB, Figg WD. The control of prostate-specific antigen expression and gene regulation by pharmacological agents. Pharmacol Rev 2001;53:73-91
• Ong WL, Romero T, Roy S, Nikitas J, Joseph D, Zapatero A, et al. Testosterone Recovery Following Androgen Suppression and Prostate Radiotherapy (TRANSPORT): A Pooled Analysis of Five Randomized Trials from the Meta-Analysis of Randomized Trials in Cancer of the Prostate (MARCAP) Consortium. Eur Urol 2024. https://doi.org/10.1016/j.eururo.2024.09.009.
• Shore ND, Saad F, Cookson MS, George DJ, Saltzstein DR, Tutrone R, et al. Oral Relugolix for Androgen-Deprivation Therapy in Advanced Prostate Cancer. N. Engl. J. Med., vol. 382, 2020, p. 2187-96. https://doi.org/10.1056/NEJMoa2004325.
• Pai HH, Pickles T, Keyes M, Jones S, Mcdonald RE, Lesperance M, et al. Randomized study evaluating testosterone recovery using shortversus long-acting luteinizing hormone releasing hormone agonists. J Can Urol Assoc 2011;5:173-9. https://doi.org/10.5489/cuaj.10102.
• Wilke DR, Parker C, Andonowski A, Tsuji D, Catton C, Gospodarowicz M, et al. Testosterone and erectile function recovery after radiotherapy and long-term androgen deprivation with luteinizing hormone-releasing hormone agonists. BJU Int 2006;97:963-8. https://doi.org/10.1111/j.1464-410X.2006.06066.x.
• D'Amico A V., Chen MH, Renshaw AA, Loffredo M, Kantoff PW. Interval to Testosterone Recovery After Hormonal Therapy for Prostate Cancer and Risk of Death. Int J Radiat Oncol Biol Phys 2009;75:10-5. https://doi.org/10.1016/j.ijrobp.2008.10.082.
• Gulley JL, Aragon-Ching JB, Steinberg SM, Hussain MH, Sartor O, Higano CS, et al. Kinetics of Serum Androgen Normalization and Factors Associated With Testosterone Reserve After Limited Androgen Deprivation Therapy for Nonmetastatic Prostate Cancer. J Urol 2008;180:1432-7. https://doi.org/10.1016/j.juro.2008.06.017.
• Inoue T, Mizowaki T, Kabata D, Shintani A, Terada N, Yamasaki T, et al. Recovery of Serum Testosterone Levels and Sexual Function in Patients Treated With Short-term Luteinizing Hormone-releasing Hormone Antagonist as a Neoadjuvant Therapy Before External Radiotherapy for Intermediate-risk Prostate Cancer: Preliminary Prospec. Clin Genitourin Cancer 2018;16:135-141.e1. https://doi.org/10.1016/j.clgc.2017.09.009.
• Mahmood J, Shamah AA, Creed TM, Pavlovic R, Matsui H, Kimura M, et al. Radiation-induced erectile dysfunction: Recent advances and future directions. Adv Radiat Oncol 2016;1:161-9. https://doi.org/10.1016/j.adro.2016.05.003.
• Paduch DA, Polzer P, Morgentaler A, Althof S, Donatucci C, Ni X, et al. Clinical and Demographic Correlates of Ejaculatory Dysfunctions Other Than Premature Ejaculation: A Prospective, Observational Study. J Sex Med 2015;12:2276-86. https://doi.org/10.1111/jsm.13027.
• Barnas J, Parker M, Guhring P, Mulhall JP. The utility of tamsulosin in the management of orgasm-associated pain: A pilot analysis. Eur Urol 2005;47:361-5. https://doi.org/10.1016/j.eururo.2004.10.020.
• Merrick GS, Wallner K, Butler WM, Lief JH, Sutlief S. Short-term sexual function after prostate brachytherapy. Int J Cancer 2001;96:313-9. https://doi.org/10.1002/ijc.1028.
• Sullivan JF, Stember DS, Deveci S, Akin-Olugbade Y, Mulhall JP. Ejaculation profiles of men following radiation therapy for prostate cancer. J Sex Med 2013;10:1410-6. https://doi.org/10.1111/jsm.12101.
• Yoon FH, Perera F, Fisher B, Stitt L. Alterations in Hormone Levels After Adjuvant Chemoradiation in Male Rectal Cancer Patients. Int J Radiat Oncol Biol Phys 2009;74:1186-90. https://doi.org/10.1016/j.ijrobp.2008.09.027.
• Yau I, Vuong T, Garant A, Ducruet T, Doran P, Faria S, et al. Risk of Hypogonadism From Scatter Radiation During Pelvic Radiation in Male Patients With Rectal Cancer. Int J Radiat Oncol Biol Phys 2009;74:1481-6. https://doi.org/10.1016/j.ijrobp.2008.10.011.
• Tomic R, Bergman B, Damber JE, Littbrand B, Löfroth PO. Effects of external radiation therapy for cancer of the prostate on the serum concentrations of testosterone, follicle-stimulating hormone, luteinizing hormone and prolactin. J Urol 1983;130:287-9. https://doi.org/10.1016/S0022-5347(17)51110-6.
• Tinkler SD, Howard GCW, Kerr GR. Sexual morbidity following radiotherapy for germ cell tumours of the testis. Radiother Oncol 1992;25:207-12. https://doi.org/10.1016/0167-8140(92)90270-5.
• Fuller DB. Testicular Dose From Prostate CyberKnife: A Cautionary Note in Regard to King et al. Int J Radiat Oncol Biol Phys 2009;73:637. https://doi.org/10.1016/j.ijrobp.2008.09.003.
• Petersen PM, Giwercman A, Daugaard G, Rørth M, Petersen JH, Skakkebæk NE, et al. Effect of Graded Testicular Doses of Radiotherapy in Patients Treated for Carcinoma-In-Situ in the Testis. J Clin Oncol 2002;20:1537-43. https://doi.org/10.1200/jco.2002.20.6.1537.
• Shapiro E, Kinsella TJ, Makuch RW, Fraass BA, Glatstein E, Rosenberg SA, et al. Effects of fractionated irradiation on endocrine aspects of testicular function. J Clin Oncol 1985;3:1232-9. https://doi.org/10.1200/JCO.1985.3.9.1232.
• King CR, Lo A, Kapp DS. Testicular Dose From Prostate CyberKnife: A Cautionary Note. Int J Radiat Oncol Biol Phys 2009;73:636-7. https://doi.org/10.1016/j.ijrobp.2008.09.004.
• Shah S, Pepin A, Forsthoefel M, Burlile J, Collins BT, Simeng S, et al. Testosterone as a Biomarker for Quality of Life (QOL) Following Androgen Deprivation Therapy (ADT) and Stereotactic Body Radiotherapy (SBRT). Cureus 2023;31:15. https://doi.org/10.7759/cureus.44440.
• Obayomi-Davies O, Chen LN, Bhagat A, Wright HC, Uhm S, Kim JS, et al. Potency preservation following stereotactic body radiation therapy for prostate cancer. Radiat Oncol 2013;8. https://doi.org/10.1186/1748-717X-8-256.
• Siglin J, Kubicek GJ, Leiby B, Valicenti RK. Time of decline in sexual function after external beam radiotherapy for prostate cancer. Int J Radiat Oncol Biol Phys 2010;76:31-5. https://doi.org/10.1016/j.ijrobp.2009.01.070.
• Pinkawa M, Gagel B, Piroth MD, Fischedick K, Asadpour B, Kehl M, et al. Erectile dysfunction after external beam radiotherapy for prostate cancer. Eur Urol 2009;55:227-34. https://doi.org/10.1016/j.eururo.2008.03.026.
• van der Wielen GJ, van Putten WL, Incrocci L. Sexual function after three-dimensional conformal radiotherapy for prostate cancer: results from a dose-escalation trial. Int J Radiat Oncol Biol Phys 2007;68:479-84. https://doi.org/10.1016/j.ijrobp.2006.12.015.
• Incrocci L. Radiotherapy for prostate cancer and sexual health. Transl Androl Urol 2015;4:124-30. https://doi.org/10.3978/j.issn.2223-4683.2014.12.08.
• Flynn KE, Lin L, Bruner DW, Cyranowski JM, Hahn EA, Jeffery DD, et al. Sexual Satisfaction and the Importance of Sexual Health to Quality of Life Throughout the Life Course of U.S. Adults. J Sex Med 2016;13:1642-50. https://doi.org/10.1016/j.jsxm.2016.08.011.
• Canadian Cancer Statistics Advisory Committee. Canadian Cancer Statistics. Canadian Cancer Statistics; 2023.
• National Comprehensive Cancer Network. Prostate Cancer (Version 4.2023). 2023. https://doi.org/https://www.nccn.org/professionals/physician_gls/pdf/prostate.pdf.
• American Society for Radiation Oncology. Model Policies. 2014. https://doi.org/https://www.astro.org/Daily-Practice/ Reimbursement/Model-Policies.

Study record dates

Study Major Dates

• Study Start (Estimated): March 16, 2026
• Primary Completion (Estimated): March 16, 2028
• Study Completion (Estimated): December 31, 2029

Study Registration Dates

• First Submitted: February 25, 2026
• First Submitted That Met QC Criteria: March 4, 2026
• First Posted (Actual): March 10, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 4, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Prostate cancer; SBRT; ADT; sexual function
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Mental Disorders; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Carcinoma; Sexual Dysfunction, Physiological; Sexual Dysfunctions, Psychological; Prostatic Neoplasms; Adenocarcinoma; Erectile Dysfunction; Physiological Effects of Drugs; Hormones, Hormone Substitutes, and Hormone Antagonists; Hormone Antagonists; Pharmacologic Actions; Chemical Actions and Uses; Androgen Antagonists
• Other Study ID Numbers: 1219

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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