Bone metastases occur commonly in patients with advance stage of malignancies, either as de novo at diagnosis or during the course of the disease. The presence of bone metastases not only cause debilitating symptoms like pain to patients, but also could significantly impact the neurological status and hence worsen their quality of life. External beam radiotherapy (EBRT) is the standard of care in symptomatic bone metastases to provide pain relief with minimal toxicities. The rapid evolution of systemic anti-cancer treatment landscape now led to longer survival of cancer patients, limited disease progression over bone may occur and warrant a more aggressive management approach with hope to offer a better symptom and disease control. Theoretically, a higher radiation dose to tumor could potentially lead to greater proportion of tumor cell kill and hence better treatment outcomes. However, this remained challenging by external beam radiotherapy due to the radiation tolerance of critical structures nearby. With the advancement in technology, radiation therapy could now be delivered by highly conformal techniques that target the tumor more precisely while sparing surrounding normal organs. Stereotactic body radiotherapy (SBRT) is one of the advancements in this aspect that had gained interest over the past years and increasing being studied in various case series and randomized controlled trials. In this presentation, the current evidence about the efficacy and toxicities of SBRT to bone metastases, either as primary treatment or re-irradiation setting, will be reviewed. Practical factors including technical issues and patient selections will also be discussed to provide insights when consider implementation of SBRT to bone metastases in daily practice.
