RT Journal Article SR Electronic T1 Prognostic Value of 99mTc-Sestamibi Washout in Predicting Response of Locally Advanced Breast Cancer to Neoadjuvant Chemotherapy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 745 OP 751 VO 43 IS 6 A1 Rosa Sciuto A1 Rosella Pasqualoni A1 Serenella Bergomi A1 Germana Petrilli A1 Patrizia Vici A1 Franca Belli A1 Claudio Botti A1 Marcella Mottolese A1 Carlo L. Maini YR 2002 UL http://jnm.snmjournals.org/content/43/6/745.abstract AB This study evaluated the role of 99mTc-sestamibi washout in the prediction of pathologic tumor response to neoadjuvant chemotherapy in 30 patients with locally advanced breast cancer. Methods: Two 99mTc-sestamibi studies were performed before and after chemotherapy for each patient. Early (10 min) and delayed (240 min) planar breast views were acquired after a 740-MBq 99mTc-sestamibi intravenous injection, and the washout rate (WOR) was computed. All patients underwent radical mastectomy with pathologic evaluation of the residual tumor size. Results: The pretherapy 99mTc-sestamibi WOR ranged from 14% to 92% (mean ± SD, 50% ± 18%). At pathologic examination, 15 patients showed no tumor response to chemotherapy and 15 patients showed an objective response to chemotherapy. The pretherapy 99mTc-sestamibi study predicted chemoresistance (WOR > 45%) in 18 of 30 patients and no chemoresistance (WOR ≤ 45%) in 12 of 30 patients. When the WOR cutoff was set at >45%, the prognostic performance of the test was indicated by a sensitivity of 100%; a specificity of 80%; positive and negative predictive values of 83% and 100%, respectively; and a likelihood ratio of 5. The repeatability of the test was good, with 80%–93% interreader agreement (κ = 0.57−0.85). Posttherapy 99mTc-sestamibi studies confirmed the pretherapy study prediction in 29 of 30 patients. Conclusion: 99mTc-Sestamibi WOR is a reliable test for predicting tumor response to neoadjuvant chemotherapy. In fact, negative findings (WOR ≤ 45%) rule out chemoresistance and positive findings (WOR > 45%) indicate a high risk of chemoresistance.