Imaging More, Changing Nothing: Are There Predictors of Unchanged Management After [18F]PSMA-1007 PET/CT in Primary Staging of High-Risk Prostate Cancer?

Background PSMA PET/CT outperforms conventional imaging (CI) in diagnostic accuracy and management impact in prostate cancer (PCa); however, in nearly three-quarters of patients undergoing primary staging, it does not alter management compared with CI. Improved patient selection is needed to prioritize this modality, particularly where access is limited. Methods This single-center ambispective study included 232 high-risk PCa patients who underwent CI (pelvic mpMRI, bone scintigraphy, and contrast-enhanced CT acquired with PET/CT) and [ 18 F]PSMA-1007 PET/CT for primary staging. Management changes were assessed using five predefined guideline-derived treatment workflows: Age, PSA, ISUP Grade Group, and pelvic mpMRI-based T, N, and M stages were evaluated as predictors of unchanged management. Results No management changes were observed in 77.2% (179/232) of patients. In the overall cohort, none of the baseline features were significantly associated with unchanged management (post hoc minimum detectable odds ratios 3.0–5.0); in a sensitivity analysis restricted to workflows #1–4 ( n = 181), pelvic mpMRI-based T3–4 stage was associated with lower odds of unchanged management (OR 0.41, 95% CI 0.20–0.82). All 17 patients with upfront pelvic mpMRI-based M1 disease and more than five lesions (9.5% of unchanged cases) underwent design-driven stratification to a systemic therapy-only workflow, where additional lesion detection cannot affect treatment decisions. Conclusion Our findings align with previous data, showing that PSMA PET/CT led to no change in imaging-based management in approximately three-quarters of PCa patients undergoing primary staging. No clinically usable predictors of unchanged management were identified; the moderate mpMRI-based T stage association in the sensitivity analysis was insufficient to guide prioritization. Upfront pelvic mpMRI-based polymetastatic disease defines, as an a priori consequence of current guideline-derived treatment workflows, a subgroup with no possibility of management change. Where access to PSMA PET/CT is limited and PSMA-targeted radioligand therapy is not being considered, this criterion could inform a prioritization strategy; prospective validation trials are needed.