Pathophyslology of Bone Metastsis And Its Implications - A Review.

ABSTRACT

In tumors with a propensity to spread to bone a significant proportion of patients who present with cancer that appears to be localized will eventually develop incurable metastatic disease. Bone metastases are common in many advanced cancers and are an avoidable yet, annoying source of skeletal morbidity. The bone mineral matrix contains numerous growth factors that are released during normal bone remodeling, providing a fertile microenvironment for tumor cell colonization and proliferation. Tumor cells then release a variety of growth factors that promote bone resorption and increase the risk of skeletal complications. Metastasis of tumor cells to bone requires a complex cascade of events involving detachment from the primary tumor site, invasion of the vasculature, migration and adherence to distant capillaries of the bone, extravasation, and proliferation. Metastatic bone lesions are classified as osteolytic or osteoblastic, based on their radiographic appearance. Bone is the third most common site of metastatic disease .Carcinomas are much more likely to metastasize to bone than sarcomas. Routine use of whole body PET/CT in restaging HNSCC can therefore, facilitate early detection of occult bone metastases and this detection often influences therapeutic decision making.