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[A case-control study on the efficacy and the optimum interval of mass screening for prostatic cancer].

PURPOSE
The efficacy and the optimum interval of mass screening for prostatic cancer were investigated by a case-control study.


MATERIALS AND METHODS
A matched pairs analysis by 1:5 was conducted between 31 cases of advanced prostatic cancer in stage C and D detected by mass screening and 155 controls of normal subjects selected at random. In all cases and controls, the history of taking part of the mass screening for last 3 years, then the estimates of odds ratios (OR) and 95% confidence intervals (95% CI) were calculated on discordant pairs of the matched analysis.


RESULTS
OR to suffer from advanced prostatic cancer was 0.22 (95% CI: 0.07-0.70) in the group to submit to mass screening 1 year ago in comparison with the group not to submit once for 3 years. According to the analysis on the interval of submission to mass screening, the effect of screening to prevent the progression to advanced stages might be valied for 1 year.


CONCLUSION
Mass screening for prostatic cancer every year might be efficient to reduce the number of patients progressing to advanced stages.