Potential of reduction in total tumor volume measured with 3D-MRI as a prognostic factor for locally-advanced breast cancer patients treated with primary chemotherapy.

For accurate assessment of the response to primary chemotherapy (PCT) for locally advanced breast cancer, we measured reduction in total tumor volume (TTV) by using three-dimensional magnetic resonance imaging (3D MRI), and examined the relationship between this reduction and patient prognosis. Fifty-one patients with locally advanced breast cancer were treated with four cycles of docetaxel (60 mg/m(2)) before surgery. Tumor size was measured with calipers, ultrasonography (US) and conventional two-dimensional (2D) MRI before and after chemotherapy. TTV was measured with 3D MRI. These and other clinicopathological parameters were statistically analyzed to determine the prognosis for the patients. Median follow-up time was 46 months (1-64 months). Of the 51 patients, 25 developed distant recurrences. Patients whose TTV decreased by 75% or more after PCT showed significantly better prognosis than others, while tumor size measured with calipers, US and 2D MRI showed no significant relationship with patient prognosis. Of the clinicopathological parameters, only reduction in TTV and histological grade showed a significant association with distant recurrence-free survival (p = 0.03 and 0.02, log-rank test), while stepwise multivariate Cox's proportional hazards analysis identified TTV as the strongest independent prognostic factor. Reduction in TTV measured with 3D MRI can be a useful prognostic factor for patients with locally advanced breast cancer treated with PCT.