After prostate cancer comes back, how high the PSA is when you start radiation therapy matters more for your survival than how aggressive the cancer looked when it was first diagnosed.
Scientific Claim
The PSA level at the initiation of salvage radiotherapy is a stronger predictor of long-term survival than preoperative PSA, Gleason score, or clinical stage in men with prostate cancer recurrence after radical prostatectomy.
Original Statement
“In the study by Kinoshita et al. only the PSA nadir had a p value < 0.0001 for the prediction of outcome. In comparison, the preoperative PSA, clinical stage, and Gleason score had higher but still significant p values: 0.001 to 0.04.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim accurately reflects the comparative statistical strength of PSA vs. traditional factors as reported in the study, using appropriate associative language.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Prospective Cohort StudyLevel 2aIn EvidenceThe relative predictive power of PSA at SRT vs. preoperative factors for 10-year survival.
The relative predictive power of PSA at SRT vs. preoperative factors for 10-year survival.
What This Would Prove
The relative predictive power of PSA at SRT vs. preoperative factors for 10-year survival.
Ideal Study Design
A prospective cohort of 5,000 men with PSA recurrence after prostatectomy, with preoperative data (Gleason, stage, PSA) and postoperative ultrasensitive PSA measurements, using multivariable Cox regression to compare hazard ratios for death from prostate cancer between PSA at SRT and preoperative variables.
Limitation: Cannot prove PSA is causally more important—only that it correlates more strongly.
Systematic Review & Meta-AnalysisLevel 1aIn EvidenceThe pooled relative importance of PSA at SRT vs. preoperative factors across all published studies.
The pooled relative importance of PSA at SRT vs. preoperative factors across all published studies.
What This Would Prove
The pooled relative importance of PSA at SRT vs. preoperative factors across all published studies.
Ideal Study Design
A meta-analysis of individual patient data from 15+ studies (n≥30,000) comparing the C-statistic (discrimination) and net reclassification improvement of PSA at SRT vs. preoperative clinical variables for predicting 10-year prostate cancer-specific mortality.
Limitation: May be confounded by differences in PSA assay sensitivity across studies.
Cross-Sectional StudyLevel 3In EvidenceWhether PSA at SRT correlates more strongly with metastasis than preoperative factors.
Whether PSA at SRT correlates more strongly with metastasis than preoperative factors.
What This Would Prove
Whether PSA at SRT correlates more strongly with metastasis than preoperative factors.
Ideal Study Design
A cross-sectional analysis of 1,000 men with PSA recurrence, comparing PSA at SRT and preoperative factors against PSMA PET/CT findings of metastatic disease, using logistic regression to determine which variable best predicts positive imaging.
Limitation: Does not assess long-term survival outcomes.
Evidence from Studies
Supporting (1)
When prostate cancer comes back after surgery, doctors use a very sensitive blood test to check PSA levels before giving radiation. This study found that the lower the PSA level is at that point, the better the chance the patient will live longer — more than what the original cancer’s features (like PSA before surgery or how aggressive it looked under a microscope) could predict.