The practice of breast self-examination results in the earlier detection and better clinical course of Japanese women with breast cancer.

Using a questionnaire survey, we analyzed the relationship between the frequency of breast self-examination (BSE) and the clinical stage and course of breast cancer in Japanese patients. BSE had been performed monthly by only 5.4% of the patients (M group), occasionally by 35.4% (O group), and not at all by 59.2% (N group). There was a positive relationship between more frequent BSE and an earlier clinical stage, the percentages of Tis/stage 0 and I for the M, O, and N groups being 83%, 44%, and 36%, respectively (P < 0.05). The mean maximum tumor diameters for the three groups were 1.7 cm, 2.5 cm, and 3.0 cm, respectively. The tumor size in the M and O groups was significantly smaller than that in the N group at P < 0.01 and P < 0.05, respectively. The percentages of patients in the M, O, and N groups who underwent breast-conserving therapy were 42%, 11%, and 19%, respectively, with patients who had performed monthly, BSE more frequently undergoing breast-conserving therapy (P < 0.05). At a median follow-up time of 34 months, 0%, 3.8%, and 7.6% of the patients from the M, O, and N groups, respectively, had died of breast cancer, the overall survival curve of the M group being significantly better than that of the N group (P < 0.01). This retrospective study suggests the positive correlation of BSE frequency with earlier detection, and a more favorable clinical course in Japanese breast cancer patients.