External beam radiotherapy in the management of spinal metastases: review of current strategies and perspectives for highly conformal irradiation modalities.

Bone metastases are frequent in advanced metastatic solid tumors. These secondary lesions are responsible for significant impairment of quality of life of patients with onset of pain, which is frequently resistant to standard analgesics. The therapeutic challenge for a patient with spinal metastasis is to maintain a quality of life as good as possible, commensurate with its life expectancy. Radiotherapy can provide efficient pain relief, but it should be integrated into a multidisciplinary approach. In the case of epidural spinal cord compression, it should be performed whenever possible after surgery. New highly conformal irradiation modalities have emerged for treatment of spinal metastases with therapeutic perspectives. Stereotactic radiosurgery could be provided for patients with single lesions or oligometastatic disease, a good general condition, absence of cord compression, and a life expectancy greater than 6 months. It is particularly promising for the treatment of classically radioresistant tumors or relapsing disease. Intensity-modulated radiotherapy, including Helical Tomotherapy, is a new perspective for treatment of multiple metastases. However, if these new techniques can provide efficient pain sedation, hindsight is currently low to judge their therapeutic benefit and these techniques are hardly available in most centers. Here, we offer a quick review of current strategies and new modalities of radiotherapy to put into perspective the place of these techniques in therapy of spinal metastases.