Reoperation rate of ductal carcinoma in situ: impact of tomosynthesis (3D) and spot magnification.

BACKGROUND: Surgical planning depends on precise preoperative assessment of the radiological extent of ductal carcinoma in situ (DCIS). Despite different modalities used, reoperation rates for DCIS due to involved margins are high. PURPOSE: To evaluate the impact of additional imaging views (spot magnification, tomosynthesis) on surgical reoperation rate of DCIS. MATERIAL AND METHODS: The retrospective single institute study includes 157 patients with biopsy-proven pure DCIS seen on mammogram as microcalcifications and treated with breast-conserving surgery. Patients have been divided into three groups according to additional imaging performed: spot magnification, tomosynthesis, and none. All breast images (mammograms, spot magnification, tomosynthesis) were reviewed and the maximum extent of pathological microcalcifications was recorded. Radiological size was compared to final histopathological size. Reoperation rate due to inadequate margins was recorded. RESULTS: Reoperation rates (25%) due to inadequate margins were as follows: spot (18%), tomosynthesis (27%), none (31%); P = 0.488. Spot magnification, tomosynthesis, and digital zoom of full-field digital mammography predicted similarly the final histopathological size. Reoperation group had a significantly greater preoperative radiological median size (26 mm vs. 20 mm; P = 0.014) as well as median size of disease on final histopathological report (29 mm vs. 14 mm; P < 0.001). Discrepancy between radiological and final histopathological size became greater with increasing DCIS extent. CONCLUSION: The main factors for reoperations are DCIS size and discordance between radiological and histopathological sizes. The use of additional imaging views (spot magnification, tomosynthesis) did not reduce reoperation rate.