SummaryIt is widely recognized that early detection of malignant cancer is associated with increased survival prospects. If regular examinations are given, then in the case of breast cancer, there is a high chance of locating lesions before they would normally be found by the patient. Such examinations are called screenings and may involve several detection modalities. The two main parameters in the design of a screening program are the frequency of examination and the sensitivity of the detection modality. Models are developed in this paper to examine the effect of screening on the sue of tumors at the time of detection. They are then used to assess the effect of the frequency and sensitivity of the screening program on the non‐recurrence rate for breast cancer. As a result of the modelling, various recommendations on screening design are give