Dynamic contrast enhanced-magnetic resonance imaging for the early evaluation of the response to docetaxel in rats with epithelial ovarian cancer

Dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) contributes to the early detection and prediction of responses to chemotherapy in cancer. The aim of the present study was to investigate the feasibility of quantitative DCE-MRI parameters for noninvasively predicting the early response to DTX in epithelial ovarian cancer (EOC). In the present study, using 7,12-dimethylbenz (A) anthracene, orthotopic EOC was induced in Sprague Dawley rats. Rats with EOC were treated with docetaxel (DTX) on day 0. DCE-MRI was applied on days 0, 3, 7, 14 and 21. On day 21, the treated tumor types were categorized into sensitive and insensitive groups according to their change in size. Quantitative DCE-MRI parameters were used to assess the early response to therapy. The experiment was performed again, the treatment group was divided into sensitive and insensitive groups according to their initially obtained cut-off values, and histopathological analyses were performed. Comparing the sensitive group with the insensitive group, there were significant differences in the percentage change in the volume transfer constant (K-trans), rate constant (k(ep)) and initial area under the curve (IAUC) from day 3 and tumor size from day 14. During the early stages of treatment (on day 3), the percentage change of K-trans combined with k(ep) produced an AUC of 1, and a sensitivity and specificity of 100 and 100%, respectively, using a cut-off value of a 17.59% reduction in K-trans and k(ep). From day 7, there were significant differences in the quantitative index percentage change in angiogenesis in the sensitive group compared with the insensitive group. The percentage change in K-trans, k(ep) and IAUC were positively correlated with the percentage of change in tumor size and angiogenesis, and negatively correlated with the percentage of change in necrosis. The results of the present study indicated that quantitative DCE-MRI parameters were superior to imaging tumor size for the early detection and prediction of the response to DTX chemotherapy in EOC.