Causes And Symptoms Of Metastatic Bone Cancer

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Introduction Metastatic bone cancer is a result of primary tumour cell spread, through direct and local invasion, and vasculature or lymphatic circulation. It is a common feature in solid tumours formed in lungs, breasts, thyroid and prostate along with multiple myelomas and renal carcinomas. One of the major signs and symptoms for patients with bone metastases is localized pain, which is often difficult to control and can be quite sever. This paper will discuss the process of metastasis, the aetiology and pathophysiology of bone metastases, and the changes that occur within bone due to metastatic spread. It will outline bone metastases signs and symptoms, and discuss radiotherapy treatment options based on patient assessments, focussing…show more content…
Cancer cells are able to overexpress the vascular endothelial growth factor (VEGF) protein. This is a signal protein that stimulates angiogenesis (lymphangiogenisis for lymph canal production) and allows the tumour to develop. This process is shown in figure 2. Figure 2. The angiogenic process. By secreting this protein, VEGF receptors in the vasculature then activate the extracellular kinase and mitogen-activated protein (MAP) kinase signal transduction pathway. This induces proteins that breakdown the blood vessels basement membrane, allowing endothelial cells to invade. The breakdown of the membrane allows fluid and proteins to escape through the vasculature. One of these proteins, matrix metalloproteinase (MMP), breaks down the extracellular matrix between the tumour and blood vessel and allows the VEGF to stimulate receptors on the new endothelial cells. This causes proliferation of the endothelial cells, tube formation and migration towards the area signalling VEGF (the tumour cells), allowing the growth of new blood vessels into the tumour. (Spyridopoulos, I. 2002). The structure of a malignant tumour is not as solid as regular tissue, in terms of cellular adhesion, and it is easier for these cells to become detached from one another. The newly formed vasculature structures are tortuous,
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