One of the most devastating aspects of advanced cancer is the development of metastatic lesions to the bone. Approximately one-third of all adenocarcinomas will result in osseous metastases and an overwhelming 70% of patients who die of cancer show osseous metastases at autopsy (1). In particular, adequate pain management continues to be an unresolved issue in a majority of these patients. Fortunately, new endovascular techniques are currently being developed in an attempt to alleviate pain associated with metastatic disease. In this chapter, we will review some of the fundamental aspects of osseous metastases and the sources of cancer pain. We will then describe the various endovascular treatments that have been used to date including the most common therapeutic agents and their applications, benefits, and side effects.

PATHOLOGY OF OSSEOUS METASTASES

With over 300,000 cases each year, secondary metastases to bone are 15 times more prevalent than primary bone tumors (1). The most common carcinomas to metastasize to bone are prostate, breast, kidney, thyroid, and lung. Some studies report that up to 90% of these cancers result in bony lesions at autopsy (1). Less common sources also include skin, cervix, and various organs of the gastrointestinal tract (see Table 1).

Metastases to bone most often occur due to hematogenous spread in what has been described as a “seed-and-soil” mechanism (1,2). It is postulated that a single cell enters the vasculature via enzymes and proteases of tumor origin.