title: The effect of colonoscopy on serum prostate specific antigen levels.
abstract: OBJECTIVE
  To evaluate, in a prospective trial, the effect of colonoscopy on serum prostate specific antigen (PSA) levels (which are known to increase after cystoscopy and prostatic needle biopsy) in men aged 50-70 years, as they commonly undergo colonoscopy and PSA screening together.
  
  
  METHODS
  Twenty-four consecutive men (mean age 61 years, range 37-78) were enrolled in the study. All subjects had their serum PSA measured 24-72 h before undergoing colonoscopy. Further values were obtained 24 h, 7 and 30 days after the procedure. The values before and after colonoscopy were compared to evaluate the effect of colonoscopy on serum PSA levels.
  
  
  RESULTS
  Of 24 patients, seven (35%) had insignificant increases at 24 h after colonoscopy; 12 (50%) patients had an insignificant increase in PSA level 30 days after the procedure. None of the 24 patients had a significant increase after colonoscopy when compared with baseline values.
  
  
  CONCLUSIONS
  Flexible colonoscopy does not adversely affect serum PSA levels. Although individuals may have a 30% daily fluctuation in serum values, this study detected no significant change in serum PSA levels after prolonged transrectal prostatic manipulation with a colonoscope.
authors.affiliation: University of California Medical School, San Francisco, CA.
authors.forename: B F
authors.initials: BF
authors.lastname: Schwartz
authors.forename: J
authors.initials: J
authors.lastname: Faught
authors.forename: J R
authors.initials: JR
authors.lastname: Jezior
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003113:Colonoscopy; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D017430:Prostate-Specific Antigen