Population-based case-control study on cancer screening.

Matched case-control studies have recently been used to evaluate the effectiveness of cancer screening. They enable us to estimate the odds ratios of dying of cancer or of getting invasive cancer. The study compares people with various patterns of screening history with those who were not screened. Criteria for eligible cases, controls, and screening histories that are compared as exposures are discussed. The results from a case-control study for evaluating screening for cervical cancer are shown as an example. Also, a study design of a case-control study for evaluating lung cancer screening in Japan is discussed, along with biases and applications of case-control studies in evaluating cancer screening.