Tumor physiologic response to combretastatin A4 phosphate assessed by MRI

Journal Article · Fri Jul 01 04:00:00 EDT 2005 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2005.03.009· OSTI ID:20698591

Dawen, Zhao ^[1]; Lan, Jiang ^[1]; Hahn, Eric W ^[1]; Mason, Ralph P ^[1]

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1. Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX (United States)

Purpose: To evaluate the effect of the vascular targeting agent, combretastatin A4 phosphate, on tumor oxygenation compared with vascular perfusion/permeability. Methods and Materials: {sup 19}F MRI oximetry and dynamic contrast-enhanced (DCE)-MRI were used to monitor tumor oxygenation and perfusion/permeability in syngeneic 13762NF rat breast carcinoma. Results: A significant drop was found in the mean tumor pO{sub 2} (23 to 9 mm Hg, p <0.05) within 90 min after treatment (30 mg/kg of combretastatin A4 phosphate) and a further decrease was observed at 2 h (mean 2 mm Hg; p <0.01). The initial changes in pO{sub 2} in the central and peripheral regions were parallel, but by 24 h after treatment, a significant difference was apparent: the pO{sub 2} in the periphery had improved significantly, and the center remained hypoxic. These data are consistent with DCE-MRI, which revealed an {approx}70% decrease in perfusion/permeability (initial area under signal-intensity curve) at 2 h (p <0.001). The initial area under signal-intensity curve recovered fully after 24 h in a thin peripheral region, but not in the tumor center. Conclusion: The response observed by DCE-MRI, indicating vascular shutdown, paralleled the pO{sub 2} measurements as expected, but quantitative pO{sub 2} measurements are potentially important for optimizing the therapeutic combination of vascular targeting agents with radiotherapy.

• OSTI ID: 20698591
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 62; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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