A Retrospective Multicenter Analysis of the Incidence of Bone-Only Disease at PSMA PET/CT in Castration Resistant Prostate Cancer Patients

SIMPLE SUMMARY: This study aimed to determine how often castration-resistant prostate cancer spreads only to the bones and to identify factors that predict this spread. The researchers looked at PSMA PET scans from 179 men. They found that 20% had cancer that had spread only to their bones, with the most common sites being the spine, ribs, and hips. Men who were diagnosed with lymph-node spread at diagnosis or who had only received hormone treatment were more likely to have bone-only spread. These findings suggest that men with bone-only disease could benefit from personalized treatment that specifically targets the bone. The study highlights the importance of PSMA PET scans in accurately detecting prostate cancer and helping doctors choose the best treatment. ABSTRACT: PSMA PET/CT has unprecedented accuracy for localization of initial or recurrent prostate cancer (PC), which can be applied in a metastasis-directed therapy approach. PSMA PET/CT (PET) also has a role in the selection of patients for metastasis-directed therapy or radioligand therapy and therapy assessment in CRPC patients. The purpose of this multicenter retrospective study was to determine the incidence of bone-only metastasis in CRPC patients who underwent PSMA PET/CT for restaging, as well as identifying potential predictors of bone-only PET positivity. The study analyzed data from 179 patients from two centers in Essen and Bologna. Results showed that 20.1% of the patients had PSMA uptake only in the bone, with the most frequent lesions located in the vertebrae, ribs, and hip bone. Half half of the patients showed oligo disease in bone and may benefit from a bone-metastasis-directed therapy. Initial positive nodal status and solitary ADT were shown to be negative predictors of osseous metastasis. The role of PSMA PET/TC in this patient population needs to be further explored in terms of its role in the evaluation and adoption of bone-specific therapies.