[Breast cancer detected by mass screening using physical examination alone]

In Tokushima prefecture, mass screening for breast cancer has been conducted using physical examination alone since 1970. Breast cancer was detected in 108 of 141,116 screened women up until 1986. The detection rate was 0.08% among total examinees, 0.12% among initial examinees, and 0.04% among subsequent examinees. Patients with breast cancer were divided into three groups. Group I consisted of 70 patients whose cancers were detected by initial screening examination. Group II consisted of 38 patients whose cancers were discovered by subsequent periodic screenings. Group III included "interval" patients, whose cancers were found in the interval within 2 years between a negative screening examination and the next screening; 19 patients were classified into this group. Serving as controls were 615 breast cancer patients who visited our outpatient clinic, independently of the screening program, during the same period as that of the mass screening. Of the 108 patients in Groups I and II, 51 patients (47%) had noticed a lump in the breast themselves by the time of the mass screening. The stage classification and nodal involvement showed significant differences between the mass screening group and the control group, but no significant differences among the three groups. The Group III cases (interval cases) were detected at an early stage, but some of these cases included patients with fast-growing tumors. When compared with cumulative survival curves according to age-matched case-control study, there was no significant difference between the patients whose tumors were detected in the mass screening and the controls.