99mTc-MIBI scintimammography and digital mammography in the diagnosis of multicentric breast cancer.

Abstract

To compare diagnostic accuracy of scintimammography (SMG) and digital mammography (DS) in the diagnosis of multicentric breast cancer. Three hundred and sixty seven women with histologically confirmed breast cancer were included in this analysis. All patients were candidates for conservative breast surgery and had cT1-3N0-1 stage of disease. Scintimammography was performed in prone position 5-10min after intravenous injection of 740MBq of technetium-99m-methoxy-isobtyl-isonitrile (99mTc-MIBI) with acquisition time of 10min for every lateral and anterior projection. Digital mammography was done in all women according to a standard clinical protocol. Final diagnosis was established by histopathology. Multicentric breast cancer was defined as 2 or more distinct invasive tumors located in more than one quadrant or additional lesions from the primary tumor of more than 4cm in size. According to histopathological examinations multicentric breast cancer was diagnosed in 47 of 367 (12.8%) patients. Scintimammography was more effective than mammography in detecting multicentric breast cancer: sensitivity: 83.0% vs 40.4% (P<0.001), specificity: 97.8% vs 95.3% (P=0.4), accuracy: 95.9% vs 88.3% (P<0.001), positive and negative predictive values: 84.8% vs 55.9% (P=0.004) and 97.5% vs 91.6% (P<0.001), respectively. Combination of DM and SMG was characterized by increased sensitivity (93.6%), worse specificity (93.4%), accuracy (93.4%) and worse predictive value (67.7%) as compared to only SMG. Scintimammography was significantly much better by all statistical parameters than DM in the detection of multicentric breast cancer. High positive predictive value of scintimammography (84.8%) advocates it as a tool for surgery and radiotherapy planning.