Temporal Trends of Metastatic Prostate Cancer in the Prostate‐Specific Membrane Antigen Positron Emission Tomography Era in the United States

INTRODUCTION: Temporal trends of metastatic prostate cancer (mPCa) in the prostate-specific membrane antigen positron emission tomography (PSMA PET) era in the United States are not known. METHODS: In the Surveillance, Epidemiology, and End Results (SEER) database (2018-2022), all PCa patients were identified. Estimated annual percentage change (EAPC) and multivariable logistic regression (MLR) models tested the effect of the PSMA PET era (2021-2022) on mPCa rate and its substages (M1a, M1b, M1c) rates. RESULTS: Overall, 236,723 PCa patients were identified. Of those, 20,450 (8.6%) harbored mPCa. mPCa rate increased from 7.9% in 2018 to 9.4% in 2022 (EAPC: +4.7%, p = 0.019). In MLR model, PSMA PET era independently predicted 1.1-fold (p < 0.001) increase in mPCa. Within mPCa patients, 1,564 (8.0%), 14,806 (72.0%), and 4,080 (20.0%) harbored M1a, M1b, and M1c substages. M1a and M1b substages rates increased in PSMA PET era (M1a: from 6.3% in 2018 to 9.1% in 2022, EAPC: +9.3%, p = 0.009; M1b: from 70.3% in 2018 to 74.7% in 2022, EAPC: +1.7%, p = 0.043), but not M1c (from 23.3% in 2018 to 16.2% in 2022, EAPC: -8.7%, p = 0.036). In MLR models, PSMA PET era independently predicted 1.3-fold increase (p < 0.001) in M1a, 1.2-fold increase (p < 0.001) in M1b, but 0.7-fold (p < 0.001) decrease in M1c. CONCLUSION: The introduction of PSMA PET resulted in an increase in the proportion of mPCa patients in the United States. Within those, M1a and M1b substages increased, but M1c decreased. These observations suggest a stage migration phenomenon, where low burden mPCa (M1a and M1b) is diagnosed more frequently at the expense of high burden mPCa (M1c).