Objecctive:

To determine whether quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) after the first cycle of neoadjuvant chemotherapy (NAC) in locally advanced breast cancer (LABC) could predict final pathologic response.

Methods:

Twenty-eight patients with LABC who had undergone NAC were enrolled. All of them were imaged using DCE-MRI with 38 phases (10 s per phase) at the baseline and were repeatedly scanned after the first cycle of treatment. DCE-MRI kinetic parameters (K

trans

K

ep

V

e

) were calculated. Subjects were divided into major histological response group and non-major histological response group according to the surgical pathologic specimen. All parameters were compared by Student t test or nonparametric test. The diagnostic performance of different parameters (including K

trans

K

ep

and V

e

) was judged by the receiver operating characteristic (ROC) curve analysis.

Results:

Nine (32.1%) of 28 patients showed major histological response and 19 (67.9%) showed non-major histological response. No difference in all pre-treatment parameters (including K

trans

K

ep

and V

e

) was found between groups (

P

＞0.05). At the end of the first cycle of treatment

the K

trans

value and K

ep

value were significantly lower than that of the baseline (

P

＜0.05)

while the changes of V

e

value during the treatment was not significant (

P

＞0.05). K

trans

wassignificantly different between major histological responders from non-major histological responders (

P

＜0.05) after a single cycle of chemotherapy. ROC curve analysis showed that the area und

er curve (AUC) of K

trans

was 0.749. When the optimal cut-off was set at 0.202

the values for sensitivity and specificity were up to 100.00% and 63.16%. The AUCs of K

ep

and V

e

were 0.667 and 0.632

respectively.

Conclusion:

Before treatment

all DCE-MRI kinetic parameters (K

trans

K

ep

V

e

) can not predict treatment response. At the end of the first cycle of treatment

K

trans

was the best predictor of major histologic response

and K

ep

and V

e

were supplementary predictors.