The effect of PSA doubling time (PSADT) and Gleason score on the PSA at the time of initial metastasis in men with biochemical recurrence after prostatectomy.

Abstract

16 Background: We previously reported on a cohort of men with biochemical recurrence after prostatectomy (n=430) who underwent observation until metastatic progression. Here, we describe the PSA at metastasis for those patients who developed metastatic disease. Methods: PSA at metastasis was defined as the PSA value collected at the time of the first occurrence of metastasis as determined by CT or bone scan. We calculated the median PSA at metastasis and the interquartile range (IQR) for the entire cohort of men with metastatic progression, and also across different strata of PSADT (≤3 vs 3-9 vs 9-15 vs ≥15 mo) and Gleason score (≤7 vs 8-10). We used Pearson's correlation coefficient (r) to examine the relationship between PSADT or Gleason score and PSA at metastasis. Results: With a median follow-up of 4 years after biochemical recurrence, 126/430 men (29.3%) had developed metastases. Sites of first metastasis included bone in 114 men (90.5%), extra-pelvic lymph nodes in 5 men (4.0%), lung in 3 men (2.4%), liver in 3 men (2.4%), and brain in 1 man (0.8%). The median PSA at the time of initial metastasis was 31.4 ng/mL (IQR, 8.8–87.5). Median PSA at metastasis across different PSADT strata is shown below (Table). There was a weak but statistically significant correlation between PSADT and 1/PSA at metastasis (r=0.20, P=0.02). There was no correlation between Gleason score and PSA at metastasis (r=0.01, P=0.83). Median PSA at metastasis was 30.3 ng/mL (IQR, 8.6–74.9) for men with Gleason ≤7 (n=69) and 34 ng/mL (IQR, 7.9–115) for men with Gleason 8-10 (n=57). Conclusions: In patients with biochemical recurrence after prostatectomy, there is an inverse correlation between PSADT and PSA at metastasis, while Gleason sum has no effect on PSA at metastasis. These data may be used by clinicians to estimate at what PSA level metastases are likely to first develop across different strata of PSADT, helping to determine when/if to initiate therapy. [Table: see text] No significant financial relationships to disclose.