A Comparison of Mass Screening for Breast Cancer Using Mammography and Physical Examination Alone in Japan.

To compare the sensivity of breast cancer screening methods by conventional physical examination and film mammography, a trial of mass screening for breast cancer using mammography was principlly carried out in asymptomatic women over 50 years of age in Tokushima Prefecture. In this trial craniocaudal and mediolateral oblique imagings of the breast using two-view film mammography and physical examination, using inspection and palpation of the breasts were performed independently. Breast cancer was detected in 8 of a total of 950 examinees by mammography alone, and no cases of breast cancer were detected by physical examination. The detection rate of breast cancer was 0.84%, that is 7 times higher than that (0.12%) obtained by conventional mass screening using physical examination alone. The detection rate increased especially in the sixth and seventh decades of life. The stage of the detected breast cancer was stage 0 (Tis) in 5 cases and stage I, with a tumor size of 1.0 cm or less, in 3 cases. All 8 cases were in the early stage, and they underwent breast conservation therapy. Based on these results, it is recommended to employ mammography in breast cancer screening for asymptomatic women aged over 50 years. We consider mammography alone may be sufficient for mass screening for breast cancer in these subjects.