Assessment of breast carcinoma by 99mtc-sestamibi scintimammography : effect of lesion site, size and histopathological characteristics

Abstract EN

This study included 83 female patients with 94 breast lesions.

All patients underwent clinical examination, Xray mammography and 99mTc- MIBI scintimammography (SMM).

Furthermore, fine needle aspiration biopsy (FNAB) was performed for 53 breast lesions prior to surgical excision.

Complete agreement between histopathological diagnosis and SMM was observed in 66 / 80 (82.5 %) malignant lesions, whereas 2 / 14 (14 %) of benign lesions had false positive results and proved to be adenoma and granuloma.

The overall sensitivity, specificity and accuracy were 83 %, 85.5 % and 83 % respectively for SMM and 62.5 %, 59.3 % and 61.4 % for x ray mammography.

This difference was statistically significant (p = 0.006).

On the other had, sensitivity, specificity and accuracy of FNAB was 91.8 %, 90 % and 91 % respectively.

SMM and FNAB did not show much significant difference in their sensitivity, specificity and accuracy (p = 0.318).

The highest diagnostic sensitivity of SMM was 87 % for the detection of invasive carcinoma measuring 1- 2 cm.

However, the sensitivity was only 29 % for the detection of breast lesions less than 1 cm.

On contrast, X-ray mammography had a higher diagnostic sensitivity of 75 % for the detection of malignant breast lesions less than 1 cm.

99mTc-MIBI scintigraphy showed a higher sensitivity of 90 % and 89 % for the diagnosis of breast carcinoma grade 3 and 4 respectively.

While, it had a lower sensitivity of 67 % and 81% for the detection of malignant lesions grade 1 and 2 respectively.

The sensitivity of 99mTc-MIBI scintimammography was not influenced by tumour pathology (invasive ductal carcinoma was 85 % and invasive lobular carcinoma was 80 %) (p = 0.22).

Presence of carcinoma in situ did not affect the diagnostic accuracy of 99mTc- MIBI.

The sensitivity of SMM for the detection of invasive carcinoma with ER + ve was higher than that for the detection of invasive carcinoma with ER-ve (86 % vs 70 % respectively) (p < 0.05).

SMM had a significantly higher sensitivity (95 %) for localizing breast lesions in the retroareolar region compared to that in the other sites (lower inner quadrant 50 %, lower outer 70% and upper inner 82 %).