Screening digital rectal examination and prostate cancer mortality: a population-based case-control study

Although digital rectal examination (DRE) for the detection of prostate cancer has been recommended by many professional groups and has become part of the general physical examination, no randomized clinical trial has demonstrated the efficacy or effectiveness of this practice. We conducted a population-based case-control study to evaluate the association between DRE and prostate cancer mortality.

With the resources of the Rochester Epidemiology Project, all 173 men who died of prostate cancer in Olmsted County from 1976 to 1991, who were resident at the time of diagnosis, were identified. For each case, two control patients were drawn from the population, matched for residence at the time of diagnosis in the case, birth date, and duration of medical record in Olmsted County. Trained nurse abstractors reviewed the community medical records for up to 10 years before the date of diagnosis in the case for mention of DRE and specific findings associated with each mention.

Case subjects were less likely than control subjects to have had any DRE in the 10 years before diagnosis (matched odds ratio [OR] = 0.51; 95% confidence interval [CI] = 0.31, 0.84). When limited to DREs without mention of signs or symptoms that might raise suspicion of prostate cancer, the association was even stronger (OR = 0.31; 95% CI = 0.19, 0.49). Adjustment for educational attainment, marital status, and comorbid conditions did little to alter the associations.

These results demonstrate a strong inverse association between DRE and prostate cancer mortality. If further research concludes this association to be causal, screening DREs may have prevented as many as 50% to 70% of deaths due to prostate cancer that might have occurred in the absence of screening.