Short-term follow-up in 6 months is unnecessary for asymptomatic breast lesions with benign concordant results obtained at ultrasonography-guided 14-gauge core needle biopsy

Background We investigated whether short-term follow-up in 6 months was appropriate for asymptomatic benign concordant lesions on ultrasonography-guided core needle biopsy (ultrasonography-guided CNB). Methods Of 1,111 lesions, 944 underwent follow-up within 4 to 9 months after CNB, and 359 of 944 underwent a 2nd follow-up within 9 to 15 months. One hundred sixty-seven underwent a 1st follow-up within 9 to 15 months. Follow-up intervals were classified according to an interval of 6 and 12 months with 2 different methods. First, 944 and 167 lesions were classified into the 6- and 12-month groups. Second, 944 and 526 lesions (sum of 167 and 359 lesions) were classified into the 6- and 12-month groups. Clinicopathologic factors were compared between the 2 groups. Results None of the benign concordant lesions were malignant; 1.4% of the lesions showed progression in the 6-month group, not significantly different from 1.2% and.8% of the 12-month group. Mean age, mean lesion size, final assessments, and specific or nonspecific pathologies were not different between the 2 groups. Conclusions Short-term follow-up in 6 months is unnecessary for asymptomatic benign concordant breast lesions at ultrasonography-guided CNB.