n.66 – BREAST SCINTIGRAPHY WITH BREAST SPECIFIC GAMMA-CAMERA (BSGC) AND DYNAMIC CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING (DCE-MRI) IN LOCAL STAGING AND TUMOR SIZE ASSESSMENT OF PRIMARY BREAST CANCER



Abstract

BACKGROUND-AIM
Both BSGC scintigraphy and DCE-MRI are emerging as useful complementary tools to conventional imaging procedures in the diagnosis of primary breast cancer (BC). The aim of the present study was to compare the accuracy of BSGC scintigraphy and DCE-MRI in preoperative local staging and tumor size assessment of BC.
METHODS
We retrospectively reviewed a series of 44 female BC patients (36-75 yrs) who preoperatively underwent BSGC scintigraphy and DCE-MRI. Scintigraphy and DCE-MRI images were compared each other and both of these were correlated to definitive histopathological findings. Correlation coefficients were calculated to assess differences in size between imaging and histopathological examination. Twenty six/44 patients had a unifocal invasive BC, 10/44 patients had a DCIS, 6/44 patients had an invasive BC plus a distinct DCIS component, while the remaining 2 patients had a multicentric invasive tumor.
RESULTS
Both procedures evidenced the index tumor ascertained at surgery in all 26 patients with unifocal invasive carcinomas. However, BSGC scintigraphy erroneously suggested the presence of additional tumor foci in 1/26 cases, while MRI did in 3/26 cases. In these 26 patients, mean lesion size was 1.876±1.44 cm at BSGC scintigraphy and 2.008±1.22 cm at DCE MRI compared to 1.765±1.20 at histopathological analysis, with a the correlation coefficient equal to r=0.743 (p<0.05) for scintigraphy and to r=0.823 (p<0.05) for MRI. In the 10 patients with DCIS, mean lesion size was 3.98±1.40 cm at scintigraphy and 4.96±1.66 cm at MRI compared to 2.89±1.79 at histology; the corresponding correlation coefficients values were r=0.512 (p>0.05) for scintigraphy and r=0.549 (p>0.05) for MRI. In the 6 patients with invasive tumors plus DCIS, BSGC gave a correct local staging in 4/6 cases, while MRI did in only 2/6 cases; MRI overestimated tumor size in 4 of these 6 cases, while BSGC did in only one and underestimated size in the remaining case. Both procedures correctly predicted multicentric disease in the 2 affected patients, in each showing the index tumor and the additional lesions that well correlated in size with histopathological findings.
CONCLUSION
Our preliminary data seem to suggest that BSGC scintigraphy is more accurate than DCE-MRI in the preoperative local staging of BC since MRI showed a higher tendency to over-stage disease. Both procedures were accurate in the assessment of invasive tumor size, while both were less effective in assessing size of DCIS.

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