RT Journal Article SR Electronic T1 Occult Prostate Cancer Effects the Results of Case-Control Studies Due to Verification Bias JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 3007 OP 3010 VO 28 IS 5B A1 TARO IGUCHI A1 CHING Y. WANG A1 NICOLAS B. DELONGCHAMPS A1 ROBERT SUNHEIMER A1 TATSUYA NAKATANI A1 GUSTAVO DE LA ROZA A1 GABRIEL P. HAAS YR 2008 UL http://ar.iiarjournals.org/content/28/5B/3007.abstract AB Background: Epidemiological studies of prostate cancer (PCA) which are based on case control comparisons may be effected by verification bias. Verification bias exists when the experimental group has verified PCA, while the control group is presumed to be cancer free, but this is not histologically verified. Materials and Methods: Review of the literature and our recent experience with case-control studies of PCA in an autopsy model. Results: When autopsied prostates were evaluated for cancer based on prostatic specific antigen <4 ng/ml, negative biopsy or both criteria, the contamination rate was 22%, 15% or 12%, respectively. The effect of contamination by occult PCA alters the odds ratio and p-value of the results. Conclusion: It is important to recognize that contamination of the control population by occult carcinomas reduces the reliability of the results. Rigorous characterization of the experimental and control groups is needed in order to preserve the integrity of the conclusions. Copyright© 2008 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved