Evaluation of RECIST, PERCIST, EORTC, and MDA Criteria for Assessing Treatment Response with Ga68-PSMA PET-CT in Metastatic Prostate Cancer Patient with Biochemical Progression: a Comparative Study.

Purpose: The aim of the study was to compare response evaluation criteria in solid tumours 1.1 (RECIST 1.1), positron emission tomography response criteria in solid tumours (PERCIST), European organisation for research and treatment of cancer (EORTC), and MD Anderson (MDA) criteria for response assessment by Gallium 68-prostate-specific membrane antigen positron emission tomography-computed tomography (Ga68-PSMA PET-CT) in metastatic adenocarcinoma prostate cancer (mPCa) patients with biochemical progression.

Methods: Eighty-eight mPCa patients with pre and post treatment Ga68-PSMA PET-CT were included. A ≥ 25% increase and ≥ 2 ng/ml above the nadir if prostate specific antigen (PSA) drop or ≥ 2 ng/ml above the baseline if PSA does not drop was considered as biochemical progression. RECIST 1.1 and MDA criteria for morphology and PERCIST and EORTC criteria for molecular response were investigated. Percentages of progressive disease (PD), partial response (PR), and stable disease (SD) were calculated. Chi-square test was used for statistical significance.

Results: Proportion of PD, SD, and PR by RECIST 1.1 and MDA criteria were 44 (50.57%), 39 (44.83%), 4 (4.6%), and 33 (39.76%), 48 (57.83%), 2 (2.41%) respectively. Proportion of PD, SD, and PR by PERCIST and EORTC criteria were 71 (80.68%), 11 (12.50%), 6 (6.82%), and 74 (84.09%), 8 (9.09%), 6 (6.82%) respectively. Chi-square test showed statistically significant ( P  < 0.05) higher proportion of progression detected by both molecular criteria as compare to both morphological criteria.

Conclusion: We concluded that for Ga68-PSMA PET-CT response evaluation, molecular criteria performed better than morphological criteria in mPCa patient with PSA progression.