Specificity of serum prostate-specific antigen determination in the Finnish prostate cancer screening trial.

Specificity of serum prostate-specific antigen determination in the
Finnish prostate cancer screening trial.
http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=17213825&cmd=showdetailview&indexed=google

Br J Cancer. 2007 Jan 15;96(1):56-60.Click here to read Links
Specificity of serum prostate-specific antigen determination in the
Finnish prostate cancer screening trial.
Määttänen L, Hakama M, Tammela TL, Ruutu M, Ala-Opas M, Juusela H,
Martikainen P, Stenman UH, Auvinen A.

Finnish Cancer Registry, Liisankatu 21 B, FIN-00170 Helsinki, Finland.

Specificity constitutes a component of validity for a screening test.
The number of false-positive (FP) results has been regarded as one of
major shortcomings in prostate cancer screening.
We estimated the specificity of serum prostate-specific antigen (PSA)
determination in prostate cancer screening using data from a randomised,
controlled screening trial conducted in Finland with 32 000 men in the
screening arm.

We calculated the specificity as the proportion of men with negative
findings (screen negatives, SN) relative to those with negative and FP
results (SN/(SN+FP)).
A SN finding was defined as either PSA</=4 ng ml(-1) or PSA 3.0-3.9 ng
ml(-1) combined with a negative ancillary test (digital rectal
examination, DRE or free/total, F/T PSA ratio). False positives were those
with positive screening test followed by a negative diagnostic
examination.
Of the 30 194 eligible men, 20 794 (69%) attended the first screening
round and 1968 (9.5%) had a screen-positive finding.
A total of 508 prostate cancers were detected at screening (2.4%).
Hence, the number of SN findings was 18 825 and the number of FP results
1358. Specificity was estimated as 0.933 (18 825 out of 20 183) with 95%
confidence interval (CI) 0.929-0.936.
Specificity decreased with age.
Digital rectal examination as ancillary examination had similar or higher
specificity than F/T PSA. In the second screening round, specificity was
slightly lower (0.912, 95% CI 0.908-0.916).
The specificity of PSA screening in the Finnish screening trial is
acceptable.
Further improvement in specificity could, however, improve acceptability
of screening and decrease screening costs.

PMID: 17213825 [PubMed - indexed for MEDLINE]


.