Advantages of prostate-specific antigen (PSA) clearance model over simple PSA half-life computation to describe PSA decrease after prostate adenomectomy.
OBJECTIVE
A population kinetic approach based on PSA clearance (CL(PSA)) may be a more rational strategy to characterize prostate-specific antigen (PSA) decrease profile after prostate surgery than the commonly used method (half-life from mono/bi-exponential models).


METHODS
We used 182 post-adenomectomy PSA concentrations from 56 benign prostatic hyperplasia patients to build, with NONMEM software, a multi-exponential and a CL(PSA) model for comparison.


RESULTS
The best multi-exponential model was PSA(t)=4.96e(-)(0.269t)+3.10e(-)(0.16t)+0.746e(+)(0.0002t) with a stable median residual PSA at 0.64 ng/mL. The best model parametrized with clearance was CL(PSA)=0.0229()(AGE/69)(3.78). Akaike information criteria and standard errors favored the CL(PSA) model. Median peripheral zone and transitional zone productions were 0.034 ng/mL/cm(3) and 0.136 ng/mL/g. A threshold at 2 ng/mL on day 90 allowed for a diagnostic of biochemical relapse diagnostic.


CONCLUSIONS
The population CL(PSA) model was superior to the multi-exponential approach for investigating individual post-adenomectomy PSA decreases.
You
Benoit
B
Université de Lyon, Lyon, F-69003, France. benoit.you@chu-lyon.fr
Perrin
Paul
P
Freyer
Gilles
G
Ruffion
Alain
A
Tranchand
Brigitte
B
Hénin
Emilie
E
Paparel
Philippe
P
Ribba
Benjamin
B
Devonec
Marian
M
Falandry
Claire
C
Fournel
Cécile
C
Tod
Michel
M
Girard
Pascal
P
D000236:Adenoma / Q000097:blood / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood / Q000378:metabolism; D001772:Blood Cell Count; D001798:Blood Proteins / Q000378:metabolism; D003404:Creatinine / Q000097:blood; D006801:Humans; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood / Q000378:metabolism*; D011470:Prostatic Hyperplasia / Q000097:blood / Q000601:surgery; D011471:Prostatic Neoplasms / Q000097:blood / Q000601:surgery*
D014408:Biomarkers, Tumor; D001798:Blood Proteins; D003404:Creatinine; D017430:Prostate-Specific Antigen