Early Response of Prostate Carcinoma Xenografts to Docetaxel Chemotherapy Monitored With Diffusion MRI

Abstract

For many anticancer therapies, it would be desirable to accurately monitor and quantify tumor response early in the treatment regimen. This would allow oncologists to continue effective therapies or discontinue ineffective therapies early in the course of treatment, and hence, reduce morbidity. This is especially true for second-line therapies, which have reduced response rates and increased toxicities. Previous works by others and ourselves have shown that water mobility, measured by diffusion-weighted magnetic resonance imaging (DW-MRI), increases early in tumors destined to respond to therapies. In the current communication, we further characterize the utility of DW-MRI to predict response of prostate cancer xenografts to docetaxel in SCID mice in a preclinical setting. The current data illustrate that tumor volumes and secreted prostate-specific antigen both respond strongly to docetaxel in a dose-responsive manner, and the apparent diffusion coefficient of water (ADC(w)) increases significantly by 2 days even at the lowest doses (10 mg/kg). The ADCw data were parsed by histogram analyses. Our results indicate that DW-MRI can be used for early detection of prostate carcinoma xenograft response to docetaxel chemotherapy.

Assessment of early docetaxel response in an experimental model of human breast cancer using DCE-MRI, ex vivo HR MAS, and in vivo 1 H MRS

“…This is not necessarily disadvantageous, as docetaxel shows cytotoxic effects even with low doses. On the other hand, docetaxel treatment of prostate xenografts showed a dose-dependent effect on tumor growth (34), although a wider span of doses was used (10-60 mg/kg).…”

Prostate Cancer: Correlation of MR Imaging and MR Spectroscopy with Pathologic Findings after Radiation Therapy–Initial Experience

“…MR imaging was performed with standard sequences and without a contrast agent. It is possible that developing further MR imaging methods (eg, use of dynamic contrast material-enhanced or diffusion imaging) would improve cancer detection and/or localization (43)(44)(45). MR spectroscopy has a low spectral resolution at 1.5 T that could be improved at higher field strengths.…”

Biexponential characterization of prostate tissue water diffusion decay curves over an extended b-factor range

“…Future studies may focus on determining whether the additional tissue characterization afforded by the biexponential parametrization can play a role in differentiating cancer from normal PZ or CG. In addition, the quantitative biexponential diffusion decay approach may also provide a more specific test of the response of prostate cancer to treatment than standard diffusion imaging which has already shown some promise for assessing tumor response to therapy (38)(39)(40)(41). Plots of the logarithm of signal decay with b-factor as extracted from the CG and PZ ROIs of all nine men.…”