Correlation of pretreatment polarographically measured oxygen pressures with quantified contrast-enhanced power doppler ultrasonography in spontaneous canine tumors and their impact on outcome after radiation therapy

Purpose: To evaluate the use of noninvasive quantified contrast-enhanced power Doppler ultrasonography as a surrogate in the estimation of tumor hypoxia measured by invasive pO2 histography in canine tumors. Material and Methods: Data of pretreatment tumor oxygenation status, tumor vascularity and blood volume, and tumor response after radiation therapy was collected in 48 spontaneous malignant oral tumors (Table 1). Tumor oxygenation status was correlated to vascularity and blood volume, and influences on outcome after treatment were analyzed. Results: Although vascularity and blood volume correlated moderately with median pO2 (r = 0.51 and 0.61; p = 0.001 and < 0.0001) and percentage of pO2 readings ≤ 2.5, 5, and 10 mmHg (r = –0.37 to –0.42; p < 0.01–0.03) for all tumors, they did not correlate within the different histology groups (p = 0.06–0.9). For all tumors, pretreatment oxygenation status, vascularity and blood volume were not found to be of prognostic value (Tables 2 and 3). Conclusion: These analyses show that quantified contrast-enhanced power Doppler ultrasonography does not represent a noninvasive indirect method to assess tumor hypoxia measured by invasive pO2 histography. Both technologies were nonprognostic indicators in spontaneous malignant canine oral tumors