Interstitial fluid pressure and blood flow in canine osteosarcoma and other tumors

This study aims to characterize interstitial fluid pressure and blood flow in naturally occurring appendicular bone tumors in dogs because high pressu re may influence the response of tumors to chemotherapy and radiation thera py. Eighteen client-owned dogs with naturally occurring appendicular bone t umors were included in this study. At the time of surgical biopsy, intersti tial fluid pressure and blood flow were measured using wick-in-needle probe s and laser Doppler flowmetry, respectively, within the soft tissue and bon y components of the lesions and in normal muscle. Interstitial fluid pressu re within the bony and soft tissue components of the tumors was significant ly higher than interstitial fluid pressure in normal muscle. Blood flow in the bony component of the tumors was significantly lower than blood flow in normal muscle, There was no significant difference between blood Bow in th e soft tissue component of the tumors compared with that in normal muscle. Appendicular bone tumors in dogs have significantly higher interstitial flu id pressure and lower blood how than do adjacent, unaffected soft tissues. The higher interstitial fluid pressure and lower blood Bow may reduce tissu e oxygenation and impede drug delivery. The effects of increased interstiti al fluid pressure and decreased blood Bow should be considered in the formu lation of treatment strategies for the clinical management of appendicular bone tumors.