Tumor-directed Radiation Therapy for Patients With the Highest Risk Category of Localized Prostate Cancer

HYPO-RT-PC boost is is an open-label, multicentre, phase II trial evaluating safety and efficacy of real-time image-guided tumor-directed ultra-hypofractionated radiation boost and lymph node irradiation for patients with node-negative high risk localized prostate cancer. 76 participants will be enrolled in the study.

Specific aims of the study are:

• To study the feasibility of ultra-hypofractionation target lesion boost for node-negative very high-risk prostate cancer together with lymph node irradiation (primary outcome).
• To study the effectiveness of ultra-hypofractionated target lesion boost for high-risk prostate cancer.
• To study the feasibility of defining focal boost during concomitant androgen deprivation therapy with advanced functional imaging methods.

Inclusion criteria

• Life expectancy >5 years
• Age ≥18 years
• World Health Organization (WHO) performance status 0-2
• Histological evidence of prostate cancer
• Classified as very high-risk according to national guidelines (2-3 of following high risk criteria: T3 / Gleason grade 8 /Prostate-specific antigen (PSA) 20-49 μg/L or and/or Gleason score 9-10 and/or PSA ≥40 μg/L
• At least one Prostate Imaging-Reporting and Data System (PI-RADS) 4-5 lesion on diagnostic Magnetic resonance imaging (MRI)
• Patients must be able to comply with the protocol
• Signed informed consent
• Adequate laboratory findings: haemoglobin (Hb) >90 g/L, absolute neutrophil count >1.0x10^9/l, platelets >75x10^9/l, bilirubin <2.0 x upper limit of normal (ULN), alanine aminotransferase (ALAT) <5x ULN and creatinine <2.0x ULN)

Exclusion criteria

• Regional or distant metastasis
• Any contraindications for MRI
• PSA >150 ng/ml
• Previous pelvic radiotherapy
• Prior prostate surgery including transurethral resection of the prostate (TURP)
• Endocrine treatment (past or present)
• Other malignancies than prostate cancer and basalioma in the past five years
• Serious disease state that makes study inclusion and treatment unsuitable
• Severe lower urinary tract symptoms (International Prostate Symptom Score (IPSS) ≥20)