EVALUATION OF NEOADJUVANT CHEMOTHERAPEUTIC RESPONSE OF LOCALLY ADVANCED BREAST-CANCER BY MAGNETIC-RESONANCE-IMAGING

BACKGROUND. The implementation of new treatment protocols for locally advanced breast cancer is currently limited by inaccurate evaluation o f response to neoadjuvant chemotherapy. A recently developed dedicated breast magnetic resonance imaging (MRI) method (RODEO MRI) was evalua ted as a tool for determining tumor response and extent of residual di sease after neoadjuvant chemotherapy. METHODS. Thirty-nine patients wi th Stage II, III, or IV breast carcinoma were prospectively evaluated prior to and following neoadjuvant chemotherapy by MRI, physical exami nation, and mammography. Assessment of response determined by the thre e methods was compared. In addition, detailed pathologic correlation o f residual disease was determined by serial sectioning of 31 mastectom y specimens from 30 patients. Nine patients had breast conservation, a nd were included in the response evaluation only. Estimates of tumor r esponse were made by both surgical and medical oncologists. Independen t interpretations of MRI studies without knowledge of clinical respons e were made by three radiologists. RESULTS. The surgical oncologists a ssessed complete response (CR), partial response (PR), and no response (NR) in 11, 22, and 7 cases, respectively. The medical oncologists as sessed CR, PR, and NR in 12, 21, and 7 cases, respectively. The surgic al and medical oncologists' clinical assessment of response agreed wit h the results of MRI in 52% and 55% of cases, respectively, and with e ach other in 30 of 40 cases (75%). Mammography correlated with MRI res ponse in only 52% of cases. However, MRI accurately predicted the path ologic determination of residual disease in 30 of 31 cases (97%). Ther e was no disagreement in the assessments of residual disease or respon se among the three radiologists. CONCLUSIONS. RODEO breast MRI accurat ely estimates residual disease after induction chemotherapy. It assess es response to neoadjuvant chemotherapy better than traditional method s of physical examination or mammography. The information obtained fro m this MRI technique may be used as an objective tool during clinical trials, and to select patients better for breast conservation after ne oadjuvant chemotherapy for locally advanced disease. (C) 1996 American Cancer Society.