The role of digital mammography, scintimammography with <sup>99m </sup>Tc-methoxyisobutylisonitrile (MIBI) and ultrasound in the diagnosis of multicentric breast cancer

Abstract

Background. The development of effective methods for diagnosing multicentric breast cancer patients (BC) is of great clinical importance, because it determines the tactics of surgical and radiation treatment. The aim of study: to compare diagnostic accuracy of scintimammography (SMG), digital mammography (MMG) and ultrasound (US) in the diagnosis of multicentric BC. Materials and methods . 410 women with histologically confirmed BC were included in this analysis. SMG was performed with dual detector SPECT unit Forte (Philips, Netherlands). Mammographic digital images were obtained on Senographe DS unit (GE Healthcare, USA). In 319 of 410 evaluated women we were able to determine results of preoperative US with high-frequency (7—18 MHz), high resolution linear array transducer. The pathological report was used as the gold standard. Multicentric BC was defined as 2 or more distinct invasive tumors occupying more than one quadrant. Detection of additional grouped calcifications of malignant type occupying a small portion of breast tissue (more than 15 pieces per 1 sq. cm) was considered as another mammographic sign of multicentric BC. Results. According to histopathological examinations multicentric BC was diagnosed in 51 of 410patients. SMG was more effective than MMG in detecting multicentric BC: sensitivity — 84.3 % vs 54.9 % (p <0.001), specificity — 98 % vs 95.8 % (p = 0.02), accuracy — 96.3 % vs 90.7 % (p = 0.04), positive and negative predictive values — 86 % vs 65.1 % (p = 0.004) and 97.8 % vs 93.7 % (p = 0.01), respectively. Histologically multicentric BC was revealed in 44 of 319 women that had US of the breasts. Sensitivity, specificity, accuracy, positive and negative predictive values for US were 52.3 %, 94.5 %, 88.7 %, 60.5 % and 92.5 %, respectively. SMG significantly (p <0.001) outperformed US for all diagnostic characteristics. Combination of MMG and SMG characterized by increased sensitivity (94.1 %), 94.2 % specificity, 94.1 % accuracy and positive predictive value of only 69,6 %. Conclusions. SMG is significantly more sensitive (84.3 %) than MMG (54.9 %) and US (52.3 %) in detection of multicentric BC. High (86 %) positive predictive value of SMG advocates it as a tool for surgery and radiotherapy planning.