The aim of this research was to reduce the interval of breast cancer by reviewing and analyzing its occurrence.

Of the 311 breast cancer patients observed at our clinic between 1998 and 2002, the 14 that had developed breast cancer within the 24 months of their previous screening examination were the subjects of this study.

Ductal carcinoma in situ (DCIS) was found in 3 patients revealing changes of, or newly developed, microcalcification. 5 patients, believed to have benign lesion, where follow-up checking was recommended, were later found to have breast cancer. There were 3 failed cases from early diagnosis of cancer due to a dense breast. In 2 cases, the cancer was thought to have progressed due to the lack of an active recommendation for a biopsy, even after suspicious abnormal findings were observed. For all the other cases, the cancer was detected early during routine follow-ups.

In case of dense breast, intense and thorough examinations including ultrasonography should be recommended because dense breast may prevent the detection of small masses. Especially, it is a fact in Korean women who carry dense breasts in many cases. Even if mass or microcalcification is thought to be benign, a biopsy should be encouraged. For a suspicious lesion, a biopsy should be recommended to a greater extent than the other follow-up measures. Routine screening examinations should be recommended once a year, but can be performed between 6 months and 2 years depending on the patients' age or degree of dense breast.