Palliative Radiotherapy for Painful Bone Metastases

Abstract

Radiotherapy is a highly successful modality to palliate pain due to bone metastases, with mild adverse effects and short treatment durations. According to previous metaanalyses, response rates and complete response rates were 59-73 and 23-34%, respectively. The median period until pain relief is 3-4 weeks, while the median period until a pain increase is 5-6 months. For uncomplicated painful bone metastases, which are defined as the presence of painful bone metastases that are not associated with impending or existing pathological fracture or existing spinal cord or cauda equine compressions, multiple randomized trials have shown that a single 8-Gy fraction regimen is equally effective as multiple fraction regimens, such as 20 Gy in 5 fractions or 30 Gy in 10 fractions. A single fraction regimen is equally effective not only in terms of response rates of pain relief but also in the period until a pain increase, incidence of spinal cord compression, incidence of pathological fracture, quality of life, as well as acute and late adverse effects. Therefore, a single fraction regimen is applicable not only for patients with a poor prognosis but also for those with a good prognosis. For patients with complicated bone metastases, multiple fraction regimens are recommended. Multiple fraction regimens are also recommended for patients with neuropathic pain. For patients who have recurrent or persistent pain after radiotherapy, reirradiation of the same sites is also effective. The response to the first irradiation is not a predictive factor of the response to reirradiation. Radiopharmaceuticals such as Strontium-89 are an important option for multifocal painful bone metastases, of which the number of anatomical sites is too high to reasonably be treated with external beam radiotherapy. Stereotactic body radiotherapy (SBRT) for spinal metastases should be used only within clinical trials.