Proposal for Systemic-Therapy Response-Assessment Criteria at the Time of PSMA PET/CT Imaging: The PSMA PET Progression Criteria

PPP for appearance of more than 2 new distant lesions, with other lesion disappearing, in 63-y-old patient with history of previous nephrectomy due to clear cell renal cell carcinoma. In 2011, patient underwent radical prostatectomy (pT3bpN0 Mx; Gleason score, 4 + 5; initial prostate-specific antigen, 11 ng/mL) plus adjuvant external-beam radiation therapy. In 2016, patient experienced biochemical recurrence, which was treated with androgen deprivation therapy. (A) Castration resistance was diagnosed in 2018, with evidence of PSMA-positive bone lesions at dorsal and lumbar spine. (B) After external-beam radiation therapy to these lesions, previously evident lesions disappeared almost completely, but other new lesions appeared. Because there were more than 2 new PSMA–positive lesions, progression was diagnosed according to PPP.

PPP for appearance of more than 2 new distant lesions in 70-y-old patient who had radical prostatectomy (Gleason score, 5 + 4; initial prostate-specific antigen, 7 ng/mL) plus adjuvant external-beam radiation therapy in 2009. In 2013, biochemical recurrence was treated with lymphadenectomy plus androgen deprivation therapy. (A) Castration resistance occurred in 2017, with evidence of multiple bone lesions on PSMA PET. (B) After enzalutamide treatment, previously evident lesions were persistent, with appearance of a few new lesions fulfilling criteria for progression according to PPP.