Tc-99m Methoxy Isobutyl Isonitrile (MIBI) scintimammography for detection of loco-regional recurrence of breast cancer: A comparative study of scintimammography, X-ray mammography and breast ultrasound imaging

Breast cancer is the most common cancer among women and the second leading cause of death in women after lung cancer. Local recurrence rate is about 1-2% per year. It is important to find a sensitive and accurate diagnostic method for early detection of recurrent tumor for planning subsequent management. The principal aim of the present study was to assess the utility of Tc-99m MIBI scintimammography in the detection of loco-regional recurrence of breast cancer in comparison with the conventionally used methods like x-ray mammography and ultrasonography. A total number of 42 patients (Age: mean= 45.55 yrs; median = 43.5; range, 22-77 yrs) suspected to have loco-regional recurrence of breast cancer on the basis of clinical examination and/or conventional imaging procedures were included in this study. All patients were subjected to planar scintimammography (SMM), SPECT imaging of the breast, x-ray mammography and Ultrasound scanning. The results were correlated with the final diagnosis arrived at by fine needle aspiration cytology (FNAC), core biopsy or definite wide local excision. Sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV) and accuracy (ACC) of scintimammography in the diagnosis of recurrent disease were found to be 82.75, 92.3, 96.0, 70.58 and 85.71% respectively; compared to 45.83, 66.6, 78.57, 31.57, 51.51 for x-ray mammography and 65.51, 69.23, 82.6, 47.36, 66.66 for Ultrasonography. Scintimammography results were correlated with x-ray mammography and ultrasonography by applying Pearson correlation. No significant correlation was found between SMM and XMM (r=0.27) or SMM and US (r=0.23). Based on the results of this study it is concluded that SMM has better diagnostic accuracy than mammography and ultrasonography in the detection of loco-regional recurrence of breast cancer. (author)