The presence of bone metastases predicts the presence of pain and is the most common cause of cancer-related pain. Although bone metastases do not involve vital organs, they may determine deleterious effects in patients with prolonged survival. Bone fractures, hypercalcaemia, neurologic deficits and reduced activity associated with bone metastases result in an overall compromise in the patient's quality of life. A metastasis is a consequence of a cascade of events including a progressive growth at the primary site, vascularization phase, invasion, detachment, embolization, survival in the circulation, arrest at the site of a metastasis, extravasion, evasion of host defense and progressive growth. Once cancer cells establish in the bone, the normal process of bone turnover is disturbed. The different mechanisms responsible for osteoclast activation correspond to typical radiologic features showing lytic, sclerotic or mixed metastases, according to the primary tumor. The release of chemical mediators, the increased pressure within the bone, microfractures, the stretching of periosteum, reactive muscle spasm, nerve root infiltration and compression of nerves by the collapse of vertebrae are the possible mechanisms of malignant bone pain. Pain is often disproportionate to the size or degree of bone involvement. A comprehensive assessment including a trusting relationship with the patient, taking a careful history of the pain complaint, the characteristics of the pain, the evaluation of the psychological status of the patient, neurological examination, the reviewing of diagnostic studies and laboratory findings, and individualization of the therapeutic approach, should precede any treatment. Radiotherapy is the cornerstone of the treatment. Low doses given in a single session are safe and effective, and reduce distress and inconvenience associated with repeated session. Radioisotopes are more imprecise in delivering specific doses of radiation, but have less toxicity and easy administration as well as effectiveness in subclinical sites of metastases, although storage, dispensing and administration should be under strict control. Chemotherapy and endocrine therapy are difficult to measure in terms of pain relief. Prophylactic fixation surgery can lead to improved survival and quality of life of patients with bone metastases. Surgical treatment should be undertaken when fracture occurs. Careful selection of patients for surgical spinal decompression is required. The potential benefits of surgical interventions have to be tempered with patient survival. The use of analgesics according to the WHO ladder is recommended. There is no clear evidence that non-steroidal anti-inflammatory drugs (NSAIDs) have a specific efficacy in malignant bone pain. The difficulty with incident pain is not a lack of response to systemic opioids, but rather that the doses required to control the incidental pain produce unacceptable side-effects at rest. Alternative measures are often required. The inhibition of bone resorption and hypercalcaemia can be reduced by the use of bisphosphonates. This class of drugs potentiate the effects of analgesics in improving metastatic bone pain. Invasive techniques are rarely indicated, but may provide analgesia in the treatment of pain resistant to the other modalities. Neural blockade should never be used as the sole modality for malignant bone pain, but should be considered as a helpful in specific pain situations. Careful appraisal and the application of a correct approach should enable the patient with bone metastases to obtain an acceptable pain relief despite the advanced nature of their malignant disease.

Malignant bone pain: pathophysiology and treatment.

Purpose The objective is to update previous meta-analyses with a systematic review of randomized palliative radiotherapy (RT) trials comparing single fractions (SFs) versus multiple fractions (MFs) Methods The analysis includes all published reports from randomized trials comparing SF or MF schedules for the treatment of painful bone metastases with localized RT A systematic review was performed using the random-effects model with Review Manager version 41 (Cochrane Collaboration, Oxford, UK) The odds ratio and 95% CI were calculated for each trial and presented in a forest plot Results A total of 16 randomized trials from 1986 onward were identified For intention-to-treat patients, the overall response (OR) rates for pain were similar for SF at 1,468 (58%) of 2,513 patients and MF RT at 1,466 (59%) of 2,487 patients The complete response (CR) rates for pain were 23% (545 of 2,375 patients) for SF and 24% (558 of 2,351 patients) for MF RT No significant differences were found in response rates Tr

Palliative Radiotherapy Trials for Bone Metastases: A Systematic Review

Purpose To present guidance for patients and physicians regarding the use of radiotherapy in the treatment of bone metastases according to current published evidence and complemented by expert opinion. Methods and Materials A systematic search of the National Library of Medicine’s PubMed database between 1998 and 2009 yielded 4,287 candidate original research articles potentially applicable to radiotherapy for bone metastases. A Task Force composed of all authors synthesized the published evidence and reached a consensus regarding the recommendations contained herein. Results The Task Force concluded that external beam radiotherapy continues to be the mainstay for the treatment of pain and/or prevention of the morbidity caused by bone metastases. Various fractionation schedules can provide significant palliation of symptoms and/or prevent the morbidity of bone metastases. The evidence for the safety and efficacy of repeat treatment to previously irradiated areas of peripheral bone metastases for pain was derived from both prospective studies and retrospective data, and it can be safe and effective. The use of stereotactic body radiotherapy holds theoretical promise in the treatment of new or recurrent spine lesions, although the Task Force recommended that its use be limited to highly selected patients and preferably within a prospective trial. Surgical decompression and postoperative radiotherapy is recommended for spinal cord compression or spinal instability in highly selected patients with sufficient performance status and life expectancy. The use of bisphosphonates, radionuclides, vertebroplasty, and kyphoplasty for the treatment or prevention of cancer-related symptoms does not obviate the need for external beam radiotherapy in appropriate patients. Conclusions Radiotherapy is a successful and time efficient method by which to palliate pain and/or prevent the morbidity of bone metastases. This Guideline reviews the available data to define its proper use and provide consensus views concerning contemporary controversies or unanswered questions that warrant prospective trial evaluation.

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Palliative radiotherapy for bone metastases: an ASTRO evidence-based guideline.

Background: Radiation therapy is effective in palliating pain from bone metastases. We investigated whether 8 Gy delivered in a single treatment fraction provides pain and narcotic relief that is equivalent to that of the standard treatment course of 30 Gy delivered in 10 treatment fractions over 2 weeks. Methods: A prospective, phase III randomized study of palliative radiation therapy was conducted for patients with breast or prostate cancer who had one to three sites of painful bone metastases and moderate to severe pain. Patients were randomly assigned to 8 Gy in one treatment fraction (8-Gy arm) or to 30 Gy in 10 treatment fractions (30-Gy arm). Pain relief at 3 months after randomization was evaluated with the Brief Pain Inventory. The Wilcoxon-Mann-Whitney test was used to compare response to treatment in terms of pain and narcotic relief between the two arms and for each stratification variable. All statistical comparisons were two-sided. Results: There were 455 patients in the 8-Gy arm and 443 in the 30-Gy arm; pretreatment characteristics were equally balanced between arms. Grade 2-4 acute toxicity was more frequent in the 30-Gy arm (17%) than in the 8-Gy arm (10%) (difference = 7%, 95% CI = 3% to 12%; P= .002). Late toxicity was rare (4%) in both arms. The overall response rate was 66%. Complete and partial response rates were 15% and 50%, respectively, in the 8-Gy arm compared with 18% and 48% in the 30-Gy arm (P = .6). At 3 months, 33% of all patients no longer required narcotic medications. The incidence of subsequent pathologic fracture was 5% for the 8-Gy arm and 4% for the 30-Gy arm. The retreatment rate was statistically significantly higher in the 8-Gy arm (18%) than in the 30-Gy arm (9%) (P<.001). Conclusions: Both regimens were equivalent in terms of pain and narcotic relief at 3 months and were well tolerated with few adverse effects. The 8-Gy arm had a higher rate of re-treatment but had less acute toxicity than the 30-Gy arm.

Randomized trial of short- versus long-course radiotherapy for palliation of painful bone metastases.

Purpose Few options are available for pain relief in patients with bone metastases who fail standard treatments. We sought to determine the benefit of radiofrequency ablation (RFA) in providing pain relief for patients with refractory pain secondary to metastases involving bone. Patients and Methods Thirty-one US and 12 European patients with painful osteolytic metastases involving bone were treated with image-guided RFA using a multitip needle. Treated patients had ≥ 4/10 pain and had either failed or were poor candidates for standard treatments such as radiation or opioid analgesics. Using the Brief Pain Inventory–Short Form, worst pain intensity was the primary end point, with a 2-unit drop considered clinically significant. Results Forty-three patients were treated (median follow-up, 16 weeks). Before RFA, the mean score for worst pain was 7.9 (range, 4/10 to 10/10). Four, 12, and 24 weeks following treatment, worst pain decreased to 4.5 (P < .0001), 3.0 (P < .0001), and 1.4 (P = .0005), respectively....

D.J. Cole

Papers

A Randomized Trial of a Single Treatment Versus Conventional Fractionation in the Palliative Radiotherapy of Painful Bone Metastases