13.07.2015 Views

Guidelines for Complications of Cancer Treatment Vol VIII Part B

Guidelines for Complications of Cancer Treatment Vol VIII Part B

Guidelines for Complications of Cancer Treatment Vol VIII Part B

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Injury or dental extractions: Any stimulus that initiatesor stimulates cell division post radiotherapy, can causemanifestation <strong>of</strong> ORN.Infection, immune deficiencies and malnutrition.Etiology Radiation injury. Trauma in the <strong>for</strong>m <strong>of</strong> dental extractions, biopsies. Infection.PathogenesisVarious theories have been proposed:160Release <strong>of</strong> histamine.Exposure <strong>of</strong> bone to radiotherapy above a critical dose,local injury; and infection (Watson, Scarborough et al.)with underlying tissue changes like thickening <strong>of</strong> arterialand arteriolar walls, loss <strong>of</strong> osteocytes and osteoblasts,filling <strong>of</strong> bony cavities with inflammatory cells.Hypoxic-hypocellular-hypovascular theory (Marx):Formation <strong>of</strong> hypoxic-hypocellular-hypovascular tissueand breakdown <strong>of</strong> tissue driven by persistent hypoxiathat can cause a chronic non-healing wound. This <strong>for</strong>msthe basis <strong>of</strong> hyperbaric oxygen therapy <strong>for</strong> ORN.Radiation-induced fibroatrophic theory: Activation anddysregulation <strong>of</strong> fibroblastic activity that leads toatrophic tissue within a previously irradiated area.Three distinct phases can be identified:Prefibrotic phase: Changes in endothelial cellspredominate, with acute inflammatory response.Constitutive organized phase: Abnormal fibroblasticactivity predominates with disorganization <strong>of</strong>extracellular matrix.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!