Introduction to Spinal Metastases

The spine is the most common skeletal site for metastatic disease and up to 10% of all patients with cancer develop spinal metastases during the course of their disease (Kakhki et al., Nucl Med Rev Cent East Eur 16(2):66-69, 2013; Zacharia et al., Indian J Surg Oncol 9(1):46-51, 2018; Laufer et al., Cancer Control 19(2):122-128, 2012). Most tumors spread to the spine via hematogenous venous circulation; however, local invasion from close proximity tumors is also observed. In concordance with relative bone mass, the thoracic spine is the most common site for spread, followed by the lumbosacral and cervical spine, respectively. With the aging population and robust development of systemic treatment options for various cancers, the prevalence of spine metastases is likely to increase over the coming years. While the vast majority are confined to the bony elements of the spine, those with epidural extension or intradural location often require treatment to preserve neurologic status and quality of life. As with systemic treatment options, various advances in multi-modality of treatment of these tumors have accelerated over the past 20 years and resulted in excellent local control rates for the majority of patients. Nonetheless, there continues to be a void in our understanding of genetic tropism for certain primary tumors to metastasize to the spine and what mutations portend a more favorable prognosis based on available treatment options, which is an active area of research. Currently, the focus of management involves timely diagnosis, close observation, and treatment when radiographic findings or clinical symptoms become burdensome.