Limitations of the study
Our study is not without limitations. First, this is a retrospective analysis and selection bias could be an issue like all studies of this kind. Second, this is a multi-institutional study and there are more than one operating surgeons who performed the operations and uro-pathologists who assessed RP specimens. Both surgeon experience and surgical technique (open, robot assisted or laparoscopic) might have influenced patient outcomes. Our study marked the date of prostate biopsy as the reference point to calculate the time to surgery, but this may not always reflect the actual duration of the disease, since patients’ first admission to the physician and timing of the prostate biopsy may differ between various institutions even within the same hospital system. An attempt to overcome bias, we stratified patients based on their D’Amico risks groups in order to provide more balanced distribution between cohorts. The median delay time in patient cohort waited longer than 90 days was nearly 4 months in our study. This is a limiting factor for this study in order to comment on longer delay times and specify a safe surgical time cut-off.