Purpose: To assess in a mouse model whether early or late components of glucose metabolism, exemplified by fluorine 18 (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET) and hyperpolarized carbon 13 (13C)-pyruvate magnetic resonance (MR) spectroscopy, can serve as indicators of response in ovarian cancer to multityrosine kinase inhibitor pazopanib. Materials and Methods: In this Animal Care and Use Committee approved study, 17 days after the injection of 2 3 106 human ovarian SKOV3 tumors cells into 14 female nude mice, treatment with vehicle or pazopanib (2.5 mg per mouse peroral every other day) was initiated. Longitudinal T2-weighted MR imaging, dynamic MR spectroscopy of hyperpolarized pyruvate, and 18F-FDG PET/computed tomographic (CT) imaging were performed before treatment, 2 days after treatment, and 2 weeks after treatment. Results: Pazopanib inhibited ovarian tumor growth compared with control (0.054 g ± 0.041 vs 0.223 g ±0.112, respectively; six mice were treated with pazopanib and seven were control mice; P < .05). Significantly higher pyruvate-tolactate conversion (lactate/pyruvate + lactate ratio) was found 2 days after treatment with pazopanib than before treatment (0.46 ± 0.07 vs 0.31 ± 0.14, respectively; P < .05; six tumors after treatment, seven tumors before treatment). This was not observed with the control group or with 18F-FDG PET/CT imaging. Conclusion: The findings suggest that hyperpolarized 13C-pyruvate MR spectroscopy may serve as an early indicator of response to tyrosine kinase (angiogenesis) inhibitors such as pazopanib in ovarian cancer even when 18F-FDG PET/CT does not indicate a response.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging