Radical prostatectomy (RP) is one of the main treatment options for localized prostate cancer (PCa), aiming to achieve complete tumor removal and cancer control. PSA kinetics following RP is of the great interests and defenitively related to oncological outcomes. Prior studies from Western population have reported that PSA levels typically become undetectable within 6 to 10 weeks after surgery. However, data concerning the timing of nadir PSA following RP in Asian populations remain scarce. Therefore, the purpose of this study is to investigate time to PSA nadir in patients after RP and potential factors associated with the time span

We retrospectively analyzed patients who underwent RP at Far Eastern Memorial Hospital between 2017 and 2024. Patients who lost to follow-up, experienced PSA persistence, received immediate initiation of hormone therapy postoperatively, and who had irregular PSA follow-up were excluded from the study. The patient demographics such as total prostate volume (TPV)( <40 vs. >40 ml), initial PSA (<20 vs. >20 ng/ml), clinical tumor stage (cT1+cT2 vs. cT3), pathology tumor stage (pT1+pT2 vs. pT3), and Gleason score (ISUP Grade Group 1-3 vs. 4-5) were reviewed. Student's t-test was used to compare the time to PSA nadir among different subgroups. Statistical analysis was performed with IBM SPSS version 27

A total of 101 patients were included in the initial dataset, and finally 74 patients were selected for analysis. The mean age was 66.19±6.73 years. Patient has median TPV 33.9 ml and initial PSA (IPSA) 9.7 ng/ml. The median time to PSA nadir was 77.0 days. There were no statistically significant differences in time to PSA nadir, regarding to different subgroups of TPV, IPSA, clinical stage, pathology stage, and ISUP Grade Group. (Figure)The observed median time to nadir aligns with previous reports from non-Asian cohorts, indicating that our local population may follow similar PSA dynamics following RP. Our current study is limited by its small sample size, and larger multi-center analyses are warranted to validate these findings

In our cohort, PSA nadir was generally reached within 2 to 3 months following RP, which is consistent with published data from Western populations. Such time span was not associated to TPV, IPSA, stage or Gleason score. Future work may focus on incorporating patients with biochemical recurrence to explore whether earlier or delayed PSA nadir may serve as a predictive factor for long-term outcomes.