Case-control study of digital-rectal screening in relation to mortality from cancer of the distal rectum.

The authors conducted a case-control study to examine the benefit of digital-rectal examination in reducing mortality from distal rectal cancer. The Kaiser Permanente Medical Care Program provides prepaid medical services to approximately 30 percent of the residents in its northern California service area. Members of the program aged 45 years and over who were diagnosed with fatal cancer of the distal rectum during the period 1971-1986 and who died before 1988 as a result of their cancer (n = 172) and matched controls were selected for the study. Information on digital-rectal examinations received in the absence of recorded symptoms during the 10 years prior to the diagnosis date of the case was obtained from medical charts. Similar proportions of cases (20.9%) and controls (23.3%) had been screened during the year before the diagnosis of the case (adjusted odds ratio = 0.96, 95% confidence interval 0.56-1.7) and during longer intervals throughout the 10 years before the diagnosis date of the case. These results suggest no efficacy of digital-rectal examination for preventing mortality from rectal cancer, although a modest effect cannot be ruled out.