A comparison between short-interval and regular-interval follow-up for BI-RADS category 3 lesions.

INTRODUCTION The aim of this study was to compare the short-interval and regular-interval follow-up in women with Breast Imaging Reporting and Data System (BI-RADS) category 3 screen imaging studies. The image stability, rate of image-detected breast cancer and stage of cancer are studied. METHODS Women who had BI-RADS 3 screen imaging studies (mammography and ultrasonography) conducted between the period January 2003 and December 2005 were retrospectively identified using the computerised database at the Department of Radiology, Ramathibodi Hospital, Thailand. Women who had known breast cancer status at two years after screening were included in the study and divided into two groups: short-interval (six months after screening) or regular-interval (one year after screening) follow-up. The two groups were compared in terms of the baseline clinicoradiologic characteristics and outcomes, including the image stability, image-detected breast cancer and the cancer stage at detection. RESULTS A total of 10,086 women underwent screen imaging studies within the study period. Of these, 1,541 (15 percent) were categorised as BI-RADS 3. Only 1,036 women (67 percent) had follow-up images done six to 12 months after screening, and 846 (82 percent of 1,036 women) also had known cancer status two years after the screening. Breast cancer was noted in seven women (a positive predictive value of 0.7 percent). There were no significant differences between the two groups of women in terms of their baseline characteristics, image stability at the initial follow-up, the rate of image-detected breast cancer and the stage of cancer at detection. CONCLUSION There were no significant differences in the effectiveness of short-interval versus regular-interval follow-up in women with BI-RADS 3 screen imaging studies.