title: Prostate specific antigen--a screening test for prostatic cancer?
abstract: A series of 287 patients referred by their family doctors with symptoms of bladder outflow obstruction were asked to attend the hospital for "pre-clinic" screening for carcinoma of prostate (CaP). Blood samples were collected from 211 patients and analysed for serum prostate specific antigen (PSA) and prostatic acid phosphatase (PAP). Thirty-six patients had a serum PSA greater than 10 micrograms/l and 7 had PAP levels greater than 5 iu/l. In no instance was the PAP elevated without an associated increase in PSA concentration. Patients with raised markers underwent further investigations which included prostatic biopsy and/or resection; 17 patients were proved to have carcinoma of the prostate, 9 of whom had distant metastases. The specificity of PSA for detecting prostate cancer in this study was 90% with a sensitivity of 89.5%, in contrast to values for PAP of 100% and 36.8%. The routine use of PAP as a marker for prostatic cancer should be abandoned. The use of PSA as a screening test in a group of patients with prostatism appears justified, but with a positive predictive value of only 47%, its use in a mass unselected screening programme is not recommended.
authors: Department of Urology, Morriston Hospital, Swansea.
authors: C S
authors: CS
authors: Powell
authors: A M
authors: AM
authors: Fielding
authors: K
authors: K
authors: Rosser
authors: A C
authors: AC
authors: Ames
authors: K C
authors: KC
authors: Vaughton
mesh_terms: D000135:Acid Phosphatase / Q000097:blood; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011467:Prostate / Q000032:analysis; D017430:Prostate-Specific Antigen; D011471:Prostatic Neoplasms / Q000175:diagnosis*
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D000135:Acid Phosphatase; D017430:Prostate-Specific Antigen