Comparison of Tc-99m maraciclatide and Tc-99m sestamibi molecular breast imaging in patients with suspected breast cancer

Abstract

Background

Molecular breast imaging (MBI) performed with ^99mTc sestamibi has been shown to be a valuable technique for the detection of breast cancer. Alternative radiotracers such as ^99mTc maraciclatide may offer improved uptake in breast lesions. The purpose of this study was to compare relative performance of ^99mTc sestamibi and ^99mTc maraciclatide in patients with suspected breast cancer, using a high-resolution dedicated gamma camera for MBI. Women with breast lesions suspicious for malignancy were recruited to undergo two MBI examinations--one with ^99mTc sestamibi and one with ^99mTc maraciclatide. A radiologist interpreted MBI studies in a randomized, blinded fashion to assign an assessment score (1-5) and measured lesion size. Lesion-to-background (L/B) ratio was measured with region-of-interest analysis.

Results

Among 39 analyzable patients, 21 malignant tumors were identified in 21 patients. Eighteen of 21 tumors (86%) were seen on ^99mTc sestamibi MBI and 19 of 21 (90%) were seen on ^99mTc maraciclatide MBI (p=1). Tumor extent measured with both radiopharmaceuticals correlated strongly with pathologic size (^99mTc sestamibi, r=0.84; ^99mTc maraciclatide, r=0.81). The L/B ratio in detected breast cancers was similar for the two radiopharmaceuticals: 1.55±0.36 (mean±S.D.) for ^99mTc sestamibi and 1.62±0.37 (mean±S.D.) for ^99mTc maraciclatide (p=0.53). No correlation was found between the L/B ratio and molecular subtype for ^99mTc sestamibi (r _s=0.12, p=0.63) or ^99mTc maraciclatide (r _s=-0.12, p=0.64). Of 20 benign lesions, 10 (50%) were seen on ^99mTc sestamibi and 9 of 20 (45%) were seen on ^99mTc maraciclatide images (p=0.1). The average L/B ratio for benign lesions was 1.34±0.40 (mean±S.D.) for ^99mTc sestamibi and 1.41±0.52 (mean±S.D.) for ^99mTc maraciclatide (p=0.75). Overall diagnostic performance was similar for both radiopharmaceuticals. AUC from ROC analysis was 0.83 for ^99mTc sestamibi and 0.87 for ^99mTc maraciclatide (p=0.64).

Conclusions

^99mTc maraciclatide offered comparable lesion uptake to ^99mTc sestamibi, in both malignant and benign lesions. There was good correlation between lesion extent and uptake measured from both radiopharmaceuticals. ^99mTc maraciclatide offered a marginal (but not significant) improvement in sensitivity over ^99mTc sestamibi. Our findings did not support an association between the uptake of either radiopharmaceutical and tumor molecular subtype.

Trial registration

ClinicalTrials.gov, NCT00888589