Timing of Radiographic Progression Relative to Prostate-Specific Antigen Kinetics in Patients with Metastatic Castration-Sensitive Prostate Cancer Receiving Upfront Androgen Receptor Signaling Inhibitor Therapy
Urology Journal,
Vol. 23 No. 04 (2026),
20 September 2026
,
Page 167-171
https://doi.org/10.22037/uj.v23i04.8771
Abstract
Purpose: Prostate-specific antigen (PSA) progression does not always coincide with radiographic progression in
patients with metastatic castration-sensitive prostate cancer (mCSPC) receiving upfront androgen receptor signaling inhibitor (ARSI) therapy. We evaluated the timing of radiographic progression according to predefined PSA
kinetic periods.
Materials and Methods: We retrospectively reviewed 82 consecutive patients with synchronous mCSPC treated
with upfront ARSI therapy between April 2018 and May 2024. The median follow-up duration was 23 months
(interquartile range [IQR], 14–38). PSA kinetics were categorized into three predefined periods: pre-PSA nadir
(treatment initiation to PSA nadir), post-PSA nadir/before PSA progression (PSA nadir to PSA progression), and
post-PSA progression. Radiographic progression events were classified according to these PSA kinetic periods.
Results: During follow-up, 33 patients (40%) experienced PSA progression and 26 (31.7%) developed radiographic
progression. Among the 26 radiographic progression events, 1 (3.8%) occurred during the pre-PSA nadir
period, 7 (26.9%) during the post-PSA nadir/before PSA progression period, and 18 (69.2%) during the post-
PSA progression period. Overall, 25 of 26 radiographic progression events (96.2%; 95% confidence interval [CI]:
81.1%–99.3%) occurred after PSA nadir. The only patient who developed radiographic progression before PSA
nadir was subsequently diagnosed with small-cell carcinoma of the prostate. PSA nadir levels and time to PSA nadir
were comparable between patients who developed radiographic progression before and after PSA progression.
Conclusion: Radiographic progression before PSA nadir was uncommon in this cohort, whereas a substantial
proportion of progression events occurred after PSA nadir but before PSA progression. These findings suggest
that PSA nadir may serve as a useful temporal reference point for radiographic surveillance during upfront ARSI
therapy. However, these observations should be considered hypothesis-generating and require validation in larger
prospective multicenter studies.
- androgen receptor signaling inhibitors
- metastatic castration-sensitive prostate cancer
- prostate-specific antigen kinetics
- radiographic progression
- upfront therapy
How to Cite
References
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