LAUSR

INTRODUCTION Supplementary ultrasound surveillance in breast cancer patients can detect additional cancers but is associated with unnecessary biopsies and follow-ups. We aim to determine, in patients with ductal carcinoma in situ (DCIS), the prevalence and factors associated with second breast cancers and the usefulness of supplementary ultrasound surveillance. This is the first study which focused on the usefulness of ultrasound surveillance in DCIS patients. METHODS DCIS patients were retrospectively analyzed to determine the prevalence and factors associated with second breast cancers. The prevalence of patients with benign biopsies, additional ultrasound follow-ups and second breast cancers, resulting from ultrasound surveillance, were calculated. RESULTS Three hundred and thirty- two patients were included. 25 (7.5%) patients developed second breast cancers after a mean follow-up of 77.7 months. Breast conservation (P= .0218), involved margins after lumpectomy (P = .0003) and shortened hormonal therapy (P= 0.0369) were associated with second cancers. Of the 314 patients who had ultrasound surveillance, ipsilateral, and contralateral ultrasounds yielded 1.7%/1.3% cancer detection, 5.8%/6.7% benign biopsies and 10.4%/15.3% additional follow-ups. Patients with involved margins after lumpectomy have ipsilateral cancer detection, benign biopsies and additional follow-ups of 4.5%, 4.5%, and 9.1% respectively. A total of 85.4% patients had mammographically dense breasts. CONCLUSION In DCIS patients, the rate of second breast cancers was 7.5%. Breast conservation, involved margins after lumpectomy and shortened hormonal therapy were associated with second cancers. Patients with involved margins after lumpectomy have the highest cancer detection rate and minimal unnecessary biopsies and follow-ups. Hence, ipsilateral breast ultrasound surveillance could be personalized for this high-risk group with mammographically dense breasts.