PSA doubling time confirmed as predictor of mortality after prostatectomy
MedWire News: The time it takes for a man's prostate-specific antigen (PSA) level to double after radical prostatectomy can be an early indication of whether he is at increased risk for overall or prostate cancer-specific mortality (PCSM), say researchers.
In a cohort of racially diverse men, older than those included in previous studies of PSA doubling time (PSADT), participants whose PSADT was under 3 months had an increased overall mortality risk compared with those whose PSADT was more than 3 months.
"The post-radical prostatectomy PSADT is a well-established prognostic variable that has been demonstrated to be associated with prostate cancer-specific mortality," explain Stephen Freedland (Duke University Medical Center, Durham, North Carolina, USA) and colleagues.
"However, many of these studies were performed at tertiary care centers and included relatively homogenous men," they add, in the journal Urology.
Therefore, the team tested whether PSADTs could predict survival in 345 post-prostatectomy patients who experienced biochemical recurrence (BCR; a single PSA level >0.2 ng/ml, two PSA levels equal to 0.2 ng/ml, or secondary treatment), from four US Veterans Affairs Medical Centers.
In all, 51% of the cohort were White, 41% Black, and 7% of other races. The median age of the men at surgery was 63 years.
PSADTs were stratified as less than 3.0 months (n=12), 3.0-8.9 months (n=84), 9.0-14.9 months (n=77), and 15.0 months or more (n=172). During the mean follow-up of 85 months after BCR, 88 patients died, 16 of prostate cancer; the median interval between BCR and death was 165 months.
After adjustment for confounding factors, multivariate analysis revealed that men with a PSADT of less than 3 months were a significant 5.48 times more likely to have a worse overall survival compared with men whose PSADT was more than 15 months.
A similar trend was also seen for men with a PSADT of 3.0-8.9 months, who were 1.70 times more likely to have worse overall survival compared with men with a PSADT of more than 15 months.
Furthermore, PCSM was associated with a short PSADT; the risk for PCSM increased a significant 544-fold among patients whose PSADT was less than 3 months compared with those whose PSADT was more than 15 months.
However, "the limited number of prostate cancer deaths in our study made assessing the exact risk difficult," note Freedland et al.
"These findings have validated previous results from tertiary care referral centers regarding the prognostic importance of PSADT," they conclude.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Sarah Guy