Monitoring the size and response of locally advanced breast cancers to neoadjuvant chemotherapy (weekly paclitaxel and epirubicin) with serial enhanced MRI.
OBJECTIVE
To determine if early cancer size reduction seen on enhanced magnetic resonance imaging (MRI) can serve as a response predictor and to correlate final tumor sizes on MRI and excised gross tumor size to microscopic findings in patients with locally advanced breast cancers treated with preoperative neoadjuvant chemotherapy.


METHODS
Thirty-three patients with advanced breast cancer entered this prospective chemotherapeutic study. Serial, dynamic, enhanced MRI was performed before chemotherapy induction, after the first course of chemotherapy and after the third course of chemotherapy prior to surgery. Responses were measured by image subtraction of tumor size on subsequent axial MRIs using the response evaluation criteria in solid tumors (RECIST). Early tumor size reduction, percentage of relative early tumor size reduction and final tumor size response were calculated and analyzed statistically. Sizes of residual tumors measured on MRI and gross tumors in excised breasts were correlated with microscopic findings.


RESULTS
Based on tumor sizes measured with enhanced MRI, four complete responders (CR), 19 partial responders (PR) and 10 non-responder were documented. Twelve (52%) of the 23 responders (CR and PR)had reached the criteria for PR (> or = 30% size reduction) after the first course of chemotherapy. All CR had a marked early size reduction (ESR) of more than 45%. Using the receiver operating characteristic (ROC) curve, a good cutoff point for early tumor size reduction was 7.4 cm, with a false positive rate of 0.1 and a false negative rate of 0.13. The percentage of ESR was 8.8%, with a false positive rate of 0.1 and a false negative rate of 0.09. Residual tumor size on MRI correlated well with microscopic findings (r = 0.982, p < 0.001) and gross tumor size in excised breasts correlated moderately with microscopic findings (r = 0.640, p < 0.001).


CONCLUSIONS
Serial, dynamic, enhanced MRI monitoring of chemotherapeutic response in patients with locally advanced breast cancer can be used to assess early response to chemotherapy and post-chemotherapy tumor size change. Although the residual tumor size on MRI correlated well with the microscopic findings, surgical determination of residual cancer load is still recommended to avoid underestimation.
Cheung
Yun-Chung
YC
Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Kwei Shan, Tao Yuan Hsien, Taiwan. alex2143@ms33.hinet.net
Chen
Shih-Cheh
SC
Su
Min-Ying
MY
See
Lai-Chu
LC
Hsueh
Swei
S
Chang
Hsien-Kun
HK
Lin
Yung-Chang
YC
Tsai
Chien-Sheng
CS
D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology; D017024:Chemotherapy, Adjuvant / Q000379:methods*; D015251:Epirubicin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008408:Mastectomy; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D017239:Paclitaxel / Q000627:therapeutic use*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012074:Remission Induction; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D015251:Epirubicin; D017239:Paclitaxel