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Updated: Aug 11, 2026
In Vivo Model for Testing Effect of Hypoxia on Tumor Metastasis
Published on: December 9, 2016
Oxygenation of spontaneous canine tumors during fractionated radiation therapy
Roger E Achermann1, Stefanie M Ohlerth, Carla Rohrer Bley
1Section of Diagnostic Imaging and Radiation Oncology, Veterinary School, University of Zurich, Switzerland.
Background And Purpose:
Tumor oxygenation predicts treatment outcome, and reoxygenation is considered important in the efficacy of fractionated radiation therapy. Therefore, the purpose of this study was to document the changes of the oxygenation status in spontaneous canine tumors during fractionated radiation therapy using polarographic needle electrodes.
Material And Methods:
Tumor oxygen partial pressure (pO(2)) measurements were performed with the Eppendorf-pO(2)-Histograph. The measurements were done under general anesthesia, and probe tracks were guided with ultrasound. pO(2) was measured before radiation therapy in all dogs. In patients treated with curative intent, measurements were done sequentially up to eight times (total dose: 45-59.5 Gy). Oxygenation status of the palliative patient group was examined before each fraction of radiation therapy up to five times (total dose: 24-30 Gy).
Results:
15/26 tumors had a pretreatment median pO(2) < or = 10 mmHg. The pO(2) values appeared to be quite variable in individual tumors during fractionated radiation therapy. The pO(2) of initially hypoxic tumors (pretreatment median pO(2) < or = 10 mmHg) remained unchanged during fractionated radiotherapy, whereas in initially normoxic tumors the pO(2) decreased.
Conclusion:
Hypoxia is common in spontaneous canine tumors, as 57.7% of the recorded values were < or = 10 mmHg. The data of this study showed that initially hypoxic tumors remained hypoxic, whereas normoxic tumors became more hypoxic.
