Radiometabolic Therapy (RMT) With 177Lu PSMA 617 in Advanced Castration Resistant Prostate Cancer (CRPC)

Inclusion Criteria: 1. Male, Age \> 18 years. 2. Patients must have histologically or cytologically confirmation of advanced prostate cancer castration resistant defined according to PCWG3 criteria 3. Measurable disease according to RECIST 1.1. criteria; also patients with bone lesions only could be enrolled 4. Patients with documented disease will be admitted to therapeutic phase only if the diagnostic PET/CT 68Ga-PSMA images demonstrate a significant uptake (tumor to background ratio \>2.5) at metastatic tumour site (or in the primary when present, or both) 5. Patients with documented radiological progression (in soft tissue and / or bone) and / or biochemical progression (sequence of 3 PSA rising values from a screening PSA value ≥ 2 ng / ml) according to PCWG3 in pre-study period, refractory or unfit to conventional standard treatments (hormonal or chemotherapeutic treatment such as abiraterone, enzalutamide and docetaxel) 6. Concomitant LHRH analogs assumption is allowed 7. Life expectancy greater than 6 months. 8. ECOG performance status \<2 9. Adequate haematological, liver and renal function: haemoglobin \>= 9 g/dL, absolute neutrophil count (ANC) \>= 1.5 x 109 /L, platelets \>= 100 x 109 /L, bilirubin ≤1.5 X upper normal limit (UNL), alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) \<2.5 X UNL (\< 5 X UNL in presence of liver metastases, creatinine \< 2 mg/dL). 10. Participant is willing and able to give informed consent for participation in the study 11. Other known malignant neoplastic diseases in the patient's medical history with a disease-free interval of less than 3 years (except for previously treated basal cell carcinoma). Exclusion Criteria: 1. Patients treated with chemotherapy and 223Ra radiotherapy within 4 weeks and treated within 2 weeks with palliative radiotherapy. 2. All acute toxic effects of any prior therapy (including surgery, radiation therapy, chemotherapy) must have resolved to a grade ≤ 1 according to National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.03 (CTCAE) 3. ECOG performance status \>2 4. Participation in another clinical trial with any investigational agents within 30 days prior to study screening. 5. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. 6. Assessed bone marrow invasion \> 50%