Background: The objective of this study was to develop a new AS protocol and compare it with the existing selected published AS protocols by examining the pathological characteristics of post-RARP specimens in patients eligible for AS. Materials and Methods: From a database of 1046 patients, 344 post-RARP patients with biopsy Gleason scores ≤ 6 prostate cancer (PCa) without neoadjuvant therapy were included. Six AS protocols were identified and evaluated for pathological and oncological end points. Four new AS criteria were proposed and evaluated. The probabilities of each end point were estimated using logistic regression modeling. Areas under the receiver operating curve were calculated for each protocol and end point. Results: Across all the selected protocols, biochemical recurrence occurred in 0 to 1.9% of patients; extracapsular extension (ECE) in 0 to 5.9%; lymph node involvement (LNI) in 0 to 1.3%; and upgrading to Gleason score ≥ 7 in 12.9% to 36.4%. We found that our new AS criteria: cT1-cT2 PCa; biopsy Gleason score ≤ 6; prostate-specific antigen ≤ 10 ng/mL; ≤ 1 positive biopsy core; and ≤ 50% core involvement compared favorably with other protocols. Area under the receiver operating curve analyses showed good predictive power of our AS criteria for the pathological and oncological end points of our study. Conclusion: Existing AS protocols do not satisfactorily predict insignificant PCas in our cohort, hence necessitating the need for new AS criteria in the era of robotic and local ablative surgeries. No patients in our cohort had biochemical recurrence, LNI, or ECE of their PCas when our protocol was applied.
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