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For the second consecutive year, the Centers for Disease Control and Prevention (CDC) and the National Cancer Institute have released an annual US Cancer Statistics report (). Published in collaboration with the North American Association of Central Cancer Registries, this report provides detailed information on cancer incidence, surveillance, epidemiology, and end results for 66 selected primary cancer sites and subsites for males (Table 1), 70 selected primary cancer sites and subsites for females (Table 2), and for all cancer sites combined (Figs. 1 and 2). In addition, these data have been analyzed with regard to geographic area, race, sex, and age (Table 3). According to the CDC and National Cancer Institute, 84% of the US population is covered in the 2000 surveillance report ().

Bone is a dynamic tissue that undergoes continuous remodeling. It goes through a balanced process that entails repeated cycles of bone resorption coupled with synthesis of new bone matrix (Fig. 1). These remodeling cycles are influenced by an individual’s age, endocrine and nutritional status, and level of physical activity. This ongoing tissue turnover is important for meeting the often conflicting need of the skeleton to maintain structural support for the body while also providing a source of ions for mineral homeostasis. The maintenance of skeletal mass in the face of continuous bone remodeling requires the coordinated activities of osteoblasts and osteoclasts, the two cell types responsible for skeletal matrix formation and resorption () (Fig. 1). Advances in our understanding of the precise mechanisms that control the cellular interactions and coupled activities of these two cell types have provided new insight into a number of diseases affecting the skeleton. These disorders are characterized by an imbalance of remodeling with subsequent increase in bone resorption, decreased bone mass, and loss of skeletal stability and integrity. This is particularly true for neoplastic diseases, in which a number of common human malignancies have a propensity to spread to the skeleton, resulting in significant morbidity and mortality from bone destruction ().

The American Cancer Society estimated that more Americans than ever, 1.33 million, were diagnosed with cancer in 2003 (). Reportedly, metastases develops in two-thirds of cancer patients (). After the lung and liver, the skeletal system is the third most common site of cancer metastasis (). These cancer metastases are also the most common skeletal tumors seen by orthopaedists, and the ratio of metastatic lesions to primary bone tumors is 25:1 (,). Delamarter et al. () reported that only 29 (1.5%) cases had primary neoplasms of the lumbar spine in their study of 1971 patients with neoplastic disease. The prevalence of metastases increases with age. Patients who are 50 yr or older are at greatest risk for the development of metastatic disease. The gender ratio varies for each type of malignancy. However, when all neoplasms with the potential to metastasize are considered, men and women are equally at risk for metastatic lesions.

Tumors arising in the vertebral body itself pose little danger to health and survival until they find a way into the larger system and either successfully metastasize or grow to a large enough size to threaten local vital organs. The barriers that must be overcome start with the basement membrane in either circumstance. Thereafter, the tumor must either demonstrate the ability to cross the vascular wall of the local capillary bed, survive in the circulation, and successfully implant elsewhere or the tumor must be able to overcome the local, physical barriers of the trabecular bone and cortical shell of the vertebra itself, the periosteum and overlying ligaments of the spinal column, and, finally, the muscular sheath with its many fascial layers and apposed parietal pleura.

Cytotoxic chemotherapy evolved from the concepts of Lissauer and Ehrlich over the last century. The initial chemotherapy protocols they devised were characterized by a lack of specificity, and walking a fine line balancing the toxicities experienced by the host and the tumor. This has been subsequently improved owing to a better understanding of tumor biology and the biochemical basis of action of the chemotherapy regimens. Radiation therapy started after the discovery of X-rays by Roentgen in 1895. Refinement of these modalities has resulted in therapeutic options for patients with several types of malignancies. Innovative modern techniques in the 1990s have provided insight into the intracellular pathways that result in sensitivity and resistance of the neoplastic cells to drug treatment.

The correct treatment of any spinal column tumor depends on a number of characteristics or factors unique to the individual patient and their individual tumor. There is a broad spectrum of therapies available to treat spinal tumors, ranging from observation to total vertebrectomy. Both undertreatment and overtreatment can lead to trouble. A successful surgical plan follows from a concise, step-wise investigational algorithm:

Spinal tumors may cause a variety of symptoms depending on their type, location, and rate of growth. The symptomatology differs depending on tumor location (e.g., extradural or vertebral column vs intradural-extramedullary vs intramedullary). Vertebral column tumors are divided into primary and metastatic. Primary tumors include neoplasms of the marrow (e.g., multiple myeloma), and tumors of the bone or the cartilage of the spine (). Metastatic spinal pathology is much more common than primary neoplastic pathology. The spine is the most common site of skeletal metastasis (). A spinal metastasis is found in as many as 70 to 90% of patients dying of cancer (,). The most common tumors that metastasize to the spine are tumors of the lung, breast, prostate, kidney, lymphoma, melanoma, and gastrointestinal tract (). In the pediatric population, spinal metastasis commonly arise from neuroblastoma, rhabdomyosarcoma, leukemia, and histiocytosis; less commonly from lymphoma, Wilms’ tumor, and primitive neuroectodermal tumor (). Meningiomas and nerve sheath tumors (schwannomas and neurofibromas) comprise the overwhelming majority of the intradural-extramedullary tumors. Astrocytoma, ependymoma, and hemangioblastoma account for the majority of the intramedullary tumors.

Each year, 1.3 million new cancers are diagnosed in the United States (). Carcinomas of the lung, breast, prostate, and kidney are the most common (–). More than 70% of these patients will develop skeletal metastases, most commonly in the spine (). Primary malignancies of the spine are not rare, but in adults, the vast majority of spine lesions represent lymphatic or hematogenous metastasis ().

Irrespective of the underlying pathology, treatment for neoplasia of the spine starts only after the disease has been identified and its extent confirmed on an objective study. Whenever there is a suspicion that cancer has involved the spine, an appropriate screening protocol should be initiated to confirm or rule out that suspicion and to provide a differential diagnosis or preliminary diagnosis that will guide initial treatment.

Multiple modalities are available for imaging the spine in patients with cancer, including conventional radiography, computed tomography (CT), radionuclide imaging, magnetic resonance imaging (MRI), functional and metabolic imaging, and interventional radiology techniques. After a careful history and physical examination, the next step in the evaluation of the patient with primary or secondary neoplastic involvement of the spine is selection of the appropriate imaging modality and its application at the appropriate region of the spine.