title: 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 with99mTc sestamibi has been shown to be a valuable technique for the detection of breast cancer. Alternative radiotracers such as99mTc maraciclatide may offer improved uptake in breast lesions. The purpose of this study was to compare relative performance of99mTc sestamibi and99mTc 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 with99mTc sestamibi and one with99mTc 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 on99mTc sestamibi MBI and 19 of 21 (90%) were seen on99mTc 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.) for99mTc sestamibi and 1.62 ± 0.37 (mean ± S.D.) for99mTc maraciclatide (p = 0.53). No correlation was found between the L/B ratio and molecular subtype for99mTc sestamibi (rs= 0.12, p = 0.63) or99mTc maraciclatide (rs= -0.12, p = 0.64). Of 20 benign lesions, 10 (50%) were seen on99mTc sestamibi and 9 of 20 (45%) were seen on99mTc maraciclatide images (p = 0.1). The average L/B ratio for benign lesions was 1.34 ±0.40 (mean ±S.D.) for99mTc sestamibi and 1.41 ±0.52 (mean ±S.D.) for99mTc maraciclatide (p = 0.75). Overall diagnostic performance was similar for both radiopharmaceuticals. AUC from ROC analysis was 0.83 for99mTc sestamibi and 0.87 for99mTc maraciclatide (p = 0.64).
  
  
  CONCLUSIONS
  99mTc maraciclatide offered comparable lesion uptake to99mTc 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 over99mTc sestamibi. Our findings did not support an association between the uptake of either radiopharmaceutical and tumor molecular subtype.
  
  
  BACKGROUND
  ClinicalTrials.gov, NCT00888589.
authors.affiliation: Department of Radiology, Mayo Clinic, Charlton 1-225, 200 First Street SW, Rochester, 55905, MN, USA. mkoconnor@mayo.edu.
authors.forename: Michael K
authors.initials: MK
authors.lastname: O'Connor
authors.affiliation: Health Sciences Research and the Kern Center for the Science of Healthcare Delivery, Mayo Clinic, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Melissa M B
authors.initials: MMB
authors.lastname: Morrow
authors.affiliation: Department of Radiology, Mayo Clinic, Charlton 1-225, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Katie N
authors.initials: KN
authors.lastname: Hunt
authors.affiliation: Department of Surgery, Mayo Clinic, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Judy C
authors.initials: JC
authors.lastname: Boughey
authors.affiliation: Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Dietlind L
authors.initials: DL
authors.lastname: Wahner-Roedler
authors.affiliation: Department of Radiology, Mayo Clinic, Charlton 1-225, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Amy Lynn
authors.initials: AL
authors.lastname: Conners
authors.affiliation: Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Rhodes
authors.affiliation: Department of Radiology, Mayo Clinic, Charlton 1-225, 200 First Street SW, Rochester, 55905, MN, USA.
authors.forename: Carrie B
authors.initials: CB
authors.lastname: Hruska
keywords: Breast cancer; Molecular breast imaging; Tc-99m NC100692; Tc-99m maraciclatide; Tc-99m sestamibi