The purpose of this retrospective study was assessment of correlation between Tc-99m sestaMIBI uptake and some prognostic factors of breast cancer. The following prognostic factors have been included in this study: size of the tumour, age of the patients, axilla node involvement, oestrogen and progesterone receptor (ER, PR) status, grading system of Bloom-Richardson and Ki-67 antigen expression.
Methods: 79 patients were enrolled in this study, with 85 lesions confirmed as primary breast cancers. Mean age of patients was 53 years. Scintimammography (SMM) was performed after intravenous injection of 740MBq. At 5-10 min after injection standard planar images were obtained in prone lateral and anterior supine views. Assessment of correlation between known prognostic factors of breast cancer and uptake of MIBI (evaluated as a tumour to background ratio-TBR) was performed used non-parametric (Kendall-tau correlation) statistical analysis.
Results: There were 85 breast cancers (73 invasive ductal carcinomas, 11 DCIS (ductal carcinoma in situ) and 1 lobular carcinoma. There was positive correlation between TBR Tc-99m MIBI uptake and size of the tumour (t = 0.19, p = 0.01), presence of axilla node involvement (t = 0.2, p = 0.006) and also grade of the IDC tumours evaluated using Bloom-Richardson's criteria (t = 0.18, 0.03). There were negative correlation between TBR and presence of PR (t = -0.16, p = 0.02) and borderline negative correlation between TBR and age of patients (t = -0.137, p = 0.06) and also TBR and ER status (t = -0.135, p = 0.065). Patients who are younger and/or have PR or ER negative cancers have higher Tc-99m MIBI uptake. Patients who presented with high grade of malignancy (B-R) also have higher uptake of radiotracer. Also those with higher uptake of radiotracer often had axillary node involvement. This would suggest that more aggressive tumours have higher uptake of Tc-99m MIBI. Finally this study suggest correlation between in vivo uptake of MIBI and some of the known prognostic factors of breast cancer.