[Role of palliative and symptomatic radiotherapy in bone metastasis]

The presence of bone metastases is a common event in the natural history of nearly all neoplasms which often affects the patient's quality of life greatly. Bone metastases may cause pain and pathologic fractures, or even a cord compression syndrome with severe neurologic symptoms. We tried to assess the optimal irradiation schedule for these patients and to discuss the use of radiopharmaceuticals.

We reviewed the literature focusing on studies investigating the efficacy of hypofractionated radiotherapy for bone metastases. We also addressed the problem of treating multiple skeletal lesions with half-body irradiation and radionuclides.

External beam irradiation achieves pain palliation in more than 75% of patients with bone metastases, even with hypofractionation down to a single-dose administration. The results of exclusive radiotherapy in the cord compression syndrome depend on a prompt diagnosis, patient presentation and the intrinsic radiosensitivity of tumor cells. Palsy can always be avoided in these patients. Half-body irradiation can achieve complete pain relief in over 20% of patients and decrease pain markedly in the remaining cases with only a single-dose fraction (6-10 Gy), within 48 hours of irradiation and with little side-effects. Better results in terms of pain relief (80% complete responses) and duration of palliation come from fractionated half-body irradiation (up to 17.5 Gy in 7 fractions), which however has a more delayed response (1-2 weeks) and higher toxicity. The use of radiopharmaceuticals has been recently reevaluated after the introduction of new nuclides: results are similar to those of external beam irradiation (up to 80% responses), but cost and hematologic toxicity are both high. Radiopharmaceuticals can be used within an integrated treatment with external beam irradiation, chemotherapy and biphosphonates.

The efficacy of external beam irradiation in the palliation of bone metastasis-related symptoms is confirmed by this literature review, even with short treatments and single-dose administrations. This is important for both patient expectations and the necessity for improved resource allocation with reference to the territorial distribution and waiting lists of radiotherapy centers. Finally, as for the role of radiopharmaceuticals, the best nuclides are not widely used yet for the high cost of the treatment, even though they provide similar results to external beam irradiation. The issue of their efficacy in combination with antiblastic drugs and/or external beam irradiation remains open and will be clarified only with further randomized clinical trials.