Quantitative histologic data are correlated with the quantitative FLT-PET data. If the correlation is higher that 0.85, this correlation is established. If this correlation is found, the inclusion of patients will be extended from 40 to 80 patients, seeing that this will give us the opportunity to correlate clinical data with the histological data. (alpha = 0.05, one-sided, beta = 0.90, assuming that an acceptable difference in sensitivity between both tests is 0 and an unacceptable difference is 0.02). If this correlation is significant, a new study will be proposed with the introduction of neoadjuvant chemotherapy, where the selection will be determined on basis of the proliferation rate.