Quantitative optical spectroscopy can identify long-term local tumor control in irradiated murine head and neck xenografts

Abstract

Noninvasive and longitudinal monitoring of tumor oxygenation status using quantitative diffuse reflectance spectroscopy is used to test whether a final treatment outcome could be estimated from early optical signatures in a murine model of head and neck cancer when treated with radiation. Implanted tumors in the flank of 23 nude mice are exposed to 39 Gy of radiation, while 11 animals exposed to sham irradiation serve as controls. Diffuse optical reflectance is measured from the tumors at baseline (prior to irradiation) and then serially until 17 days posttreatment. The fastest and greatest increase in baseline-corrected blood oxygen saturation levels are observed from the animals that show complete tumor regression with no recurrence 90 days postirradiation, relative to both untreated and treated animals with local recurrences. These increases in saturation are observed starting 5 days posttreatment and last up to 17 days posttreatment. This preclinical study demonstrates that diffuse reflectance spectroscopy could provide a practical method far more effective than the growth delay assay to prognosticate treatment outcome in solid tumors and may hold significant translational promise.

Imaging Tumor Hypoxia to Advance Radiation Oncology

“…Vishwanath et al recently demonstrated the potential clinical relevance of this technique by showing that early changes in oxygenation in response to radiation treatment are predictive of local tumor control in a xenograft model (229). Further, in another study, the non-invasive monitoring of intra-tumor drug concentration using fluorescence diffuse reflectance spectroscopy predicted the tumor response to doxorubicin in vivo (165).…”

Chemotherapeutic drug-specific alteration of microvascular blood flow in murine breast cancer as measured by diffuse correlation spectroscopy

“…Even though there have been several longitudinal therapy monitoring studies on animal cancer models with diffuse optical spectroscopy [51,60] and/or diffuse correlation spectroscopy [61,62], this study has several unique and noteworthy aspects in the study design, data analysis method, and findings. First, the tumor model based on orthotopically implanted syngeneic tumors was chosen since it is regarded to be more predictive of responses than ectopic tumors [63].…”

Experimental validation of an inverse fluorescence Monte Carlo model to extract concentrations of metabolically relevant fluorophores from turbid phantoms and a murine tumor model

“…11,51,52,54 The overall strategy of diffuse reflectance and fluorescence spectroscopy using our scalable inverse Monte Carlo models is to ultimately provide a powerful tool to quantitatively, rapidly and non-destructively examine bioenergetics of living tissues and in particular, cancers by simultaneously being able to report on the three axes of energy production: vascular oxygenation, mitochondrial activity (TMR), and glycolysis (2-NBDG, NADH).…”