Breast-Specific Gamma Imaging and Locally Advanced Breast Cancer Undergoing Neoadjuvant Chemotherapy

Locally advanced breast cancer (LABC) is usually treated with neoadjuvant chemotherapy followed by surgery. At present, monitoring of tumor responses to chemotherapy is primarily carried out using physical examination at the beginning of each chemotherapy cycle. Differentiating viable tumor tissue from inflammation or fibrotic scar tissue can be difficult. There is a growing body of evidence that newer imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI) may be better at determining whether or not the tumor is actually shrinking, but their sensitivity and specificity were not ideal. Breast-specific gamma imaging (BSGI) using 99mTcsestamibi is a relatively new nuclear medicine imaging technique for breast tumor detection. BSGI shows higher sensitivity than conventional scintimammography in the detection of small breast cancer lesions owing to its high resolution. BSGI is a useful complementary tool to ultrasound, mammography and MRI in breast cancer diagnosis, especially in dense breasts and multifocal or multicentric disease; however, little is known about the ability of BSGI to predict of clinical and pathological response to neo-adjuvant chemotherapy in patients with locally advanced breast cancer. The purpose of this study is to determine the sensitivity and specificity of BSGI in evaluating tumor responses to chemotherapy in patients with LABC and compare this with physical examination, ultrasound, mammography and MRI, which is the current conventional standard of care. A prospective cohort study design will be conducted. Patients with LABC who receive chemotherapy will undergo physical examination, ultrasound, MRI, and BSGI at baseline, midway, and at the completion of chemotherapy. Approximately 100 patients will be recruited over a 2-year period. This study will give clinicians further insight into the usefulness of ultrasound, MRI, and BSGI in monitoring treatment responses in patients with LABC. This could potentially lead to changes in clinical management of these patients.