Influence of the docetaxel administration period (neoadjuvant or concomitant) in relation to HIFU treatment on the growth of Dunning tumors: results of a preliminary study

The objective of this study was to evaluate mechanisms of the synergy between high intensity-focused ultrasound (HIFU) and docetaxel and to determine the best sequence of chemotherapy administration in relation to HIFU treatment for obtaining optimum control of tumoral growth. A total of 15 days after s.c. implantation of the tumor, 52 Copenhagen rats studied were randomized in 4 groups of 13: controls, docetaxel alone (group 1), HIFU and docetaxel concomitant (group 2) and HIFU and docetaxel administered 24 h before treatment (group 3). The number of HIFU shots was calculated in order to cover 75% of the tumor volume. The effects of docetaxel, HIFU and their interaction on tumor volumes were analyzed using a linear regression. The distributions of the tumor volumes were significantly greater in the control group than in the group 1 ( P =0.002) and than in both groups 2 and 3 ( P