Prospective Evaluation of 68-Ga-prostate Specific Membrane Antigen (PSMA)-Positron Emission Tomograph (PET) and Early Prostatic Specific Antigen (PSA) Kinetics During Salvage Radiotherapy for Personalizing the Management of Men With Relapse of Prostate Cancer After Radical Prostatectomy

Prospective Evaluation of 68-Ga-PSMA -PET and Early PSA Kinetics During Salvage Radiotherapy for Personalizing the Management of Men With Relapse of Prostate Cancer After Radical Prostatectomy

This is an open-label, phase II trial in patients with PSA recurrence after prostatectomy. Patients entering the study will all receive initial 50 Gray (Gy) radiotherapy (25 x 2Gy) to the prostate bed and thereafter be classified as either responders or non-responders depending on PSA response at fifth week of radiotherapy.

A 68-Ga- PSMA-PET is done before start of radiotherapy, and analyzed before fifth treatment week in order to identify cancer lesions in patients with poor PSA response. Patients with PSA response after 5 weeks of radiotherapy will not receive any subsequent therapy, whilst patients with poor PSA response may be in need for additional therapy such as radiotherapy to lymph node metastases and/or boost fractions to local recurrence. Patients with more than 3 lymph node metastases or distant metastases will not receive any more radiotherapy, but individualized systemic therapy will be started.

Inclusion Criteria:

• Histological evidence of prostate cancer in the radical prostatectomy specimen
• At least 2 rising PSA values, of which the last ≥ 0.15 ng/ml
• Tumor, regional nodes, metastasis (TNM): any T, N0/x, M0/x
• Age: 18 years or older
• World Health Organization (WHO) performance status 0-1
• Life expectancy > 10 years
• Adequate laboratory findings: hematological: hemoglobin > 90 g/L (may be transfused to maintain or exceed this level) absolute neutrophil count (ANC) ≥ 1,0 x 109/L, platelets ≥ 75 x 109/L hepatic: bilirubin ≤ 1.5 x upper limit of normal (ULN), alanine aminotransferase (ALAT) ≤ 5 x ULN renal: creatinine ≤ 1.5 x ULN
• Signed written informed consent
• The patient must be able to comply with the protocol

Exclusion Criteria:

• Evidence of metastasis on imaging or in specimen (e.g. N1 at lymph-node dissection)
• Prior or ongoing treatment with hormones (antiandrogens, GnRH)
• Prior radiotherapy to the pelvis
• Previous malignancy other than prostate cancer and basalioma the past 5 years.
• Clinically significant (i.e. active) cardiovascular disease e.g. myocardial infarction (≤ 6 months), unstable angina, New York Heart Association (NYHA) grade III-IV congestive heart failure
• Severe pulmonary disease e.g. pulmonary fibrosis
• Any other serious or uncontrolled illness which in the opinion of the investigator makes it undesirable for the patient to enter the trial