title: Serendipity in detecting disease in low prostate-specific antigen ranges.
abstract: OBJECTIVE
  To assess the magnitude of prostate cancer detection by serendipity (the coincidental detection of prostate cancer during the evaluation of an abnormal screening test result) when a digital rectal examination (DRE) and transrectal ultrasonography (TRUS) are used as initial screening tests for prostate cancer in men with low levels of prostate-specific antigen (PSA; 0.0-3.9 ng/mL).
  
  
  METHODS
  In all, 117 participants of a population-based screening study were diagnosed with prostate cancer after a standard evaluation of an abnormal screening test result; 49 underwent radical prostatectomy. Serendipity was defined as either: (i) the presence of prostate cancer opposite to the side that raised suspicion for cancer on DRE and/or TRUS; (ii) a negative lesion-directed biopsy while cancer was present in one or more of the cores of the sextant biopsy; (iii) a tumour volume of < 0.5 mL on radical prostatectomy.
  
  
  RESULTS
  Depending on the definition, 27-63% of prostate cancers detected at low PSA values were detected coincidentally and not as a result of a true-positive test result. The proportion of cancers detected by serendipity was inversely correlated with serum PSA level.
  
  
  CONCLUSIONS
  A relatively high proportion of prostate cancers diagnosed in men with low PSA levels, and in which a biopsy was prompted by a suspicious DRE and/or TRUS, are considered to be detected by chance only. As these cancers are mostly small (< 0.5 mL), with potentially low biological aggressiveness, relying on serendipity seems disadvantageous in prostate-cancer screening. The level of serendipity in prostate cancer detection, the poor performance of the screening test, and high inter-observer variability, casts further doubt on the utility of DRE (and TRUS) as initial screening tests for prostate cancer in population-based screening.
authors.affiliation: Department of Pathology, Josephine Nefkens Institute, Erasmus University Rotterdam, The Netherlands. vis@path.azr.nl
authors.forename: A N
authors.initials: AN
authors.lastname: Vis
authors.forename: R
authors.initials: R
authors.lastname: Kranse
authors.forename: M
authors.initials: M
authors.lastname: Roobol
authors.forename: Th H
authors.initials: TH
authors.lastname: van der Kwast
authors.forename: F H
authors.initials: FH
authors.lastname: Schröder
mesh_terms: D000368:Aged; D001706:Biopsy / Q000379:methods; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods / Q000592:standards; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D014463:Ultrasonography
chemical_list: D017430:Prostate-Specific Antigen