Does pretreatment PSA add to predicting long-term survival from prostate cancer?
Theodore Robnett, MD
OncoLink Assistant Editor
Last Modified: May 21, 2000
Presenter: M. Roach III
Affiliation: Univ of California San Francisco, Univ of Michigan
Numerous prognostic indicators, such as Gleason
score and tumor stage are known to be significant
in assessing risk of recurrence of or death from
prostate cancer. Although prostate specific antigen (PSA) is useful in predicting recurrence,
its role as an independent prognostic indicator
relative to other staging is less clear, given
the relatively short time PSA has been in use
compared to the long natural history of this
disease. This study was performed to determine
whether pre-treatment PSA level helped predict
Materials and Methods:
- Pre-established risk groups from RTOG criteria
based on T stage and Gleason score were analyzed
for 4 year freedom from biochemical failure
(FFBCF) based on PSA stratification.
- 4 RTOG risk groups were examined: 1. T1-2,
Gleason Score (GS) 2-6; 2. T3, GS 2-6 or T1-2, GS
7; 3. T1-2, GS 8-10 or T3, GS 7; 4. T3, GS 8-10.
4 year FFBCF was then examined for pre-treatment
PSA (pPSA) < 10 versus pPSA > 20.
- Patients from UCSF and U of Michigan treated
with radiation therapy alone with pPSAs available
- Four FFBCF rates when stratified by RTOG risk
group matched the 15-year disease specific
survival in the larger RTOG group.
- In risk groups 1,2, and 3, pPSA added
prognostic information. The 4-year FFBCF for low
and high pPSA were 83% versus 47% in group 1.,
76% versus 45% in group 2, and 65% versus 25% in
group 3 (p < 0.001). Group 4 was not significant
(27% versus 28%).
- The ASTRO consensus definition for FFBCF at 4
years is strongly correlated with the expected 15
year DSS stratified by RTOG risk groups.
- Incorporating pPSA should improve our ability
to predict death due to prostate cancer.
- Risk group 4 patients are candidates for
systemic therapy regardless of PSA.
- This analysis supports pPSA as an independent
prognostic indicator in all but the highest risk
- Many patients with higher risk disease are
receiving pre-treatment, concurrent, or post-
treatment androgen ablation, or a combination of
these. How this therapy will effect disease
outcome and the significance of each prognostic
variable is uncertain.