Image-Guided Biopsies to Identify Mechanisms of Resistance in Patients With Metastatic Castration Resistant Prostate Cancer Treated With 177Lu-PSMA Radioligand Therapy

Inclusion Criteria:

* Volunteer patient
* Histologically confirmed prostate cancer
* Eligible for 177Lu-PSMA-617 under expanded access protocol (IRB# 21-5010) or as part of an approved trial
* Based on positron emission tomography (PET)/computed tomography (CT) images: Evidence of lymph node or soft tissue metastatic disease amenable to image-guided biopsy
* Platelets \> 75,000/ul within 14 days prior to biopsy
* Prothrombin time (PT) or International normalized ratio (INR) and a partial thromboplastin time (PTT) \< 1.5 times the institutional upper limit normal (ULN) within 14 days prior to biopsy
* Patients on warfarin, aspirin, or other anti-coagulants are eligible provided they are deemed able to tolerate discontinuation of anti-coagulation for one week prior to the biopsy. Conversion to low molecular weight heparin prior to biopsy is permitted per local standard operating procedures, provided there is agreement regarding the procedure between the treating physician, the interventional radiologist and the principal investigator (PI)

Exclusion Criteria:

* Patients with significant congenital or acquired bleeding disorders (e.g. von Wildebrand's disease, acquired bleeding factor inhibitors) are not eligible