Radionuclide treatment of painful bone metastases in patients with breast cancer: A systematic review

Bone-seeking radionuclides, such as Sr-89, Sm-153, and Re-186, have been shown to have an effect on pain from bone metastasis in prostate cancer. The effect on bone pain in other cancer types, including breast cancer, remains unclear. The purpose of the study was to perform a systematic review of the use of radioisotopes for pain relief in metastatic breast cancer. A literature search was performed in PubMed, EMBASE, and Web of Science (1970 to September 2009) for clinical studies with a primary outcome of pain, performance status, or quality of life. Eligibility criteria were the following: (1) the trial must include at least 10 breast cancer patients with painful bone metastasis, (2) the radionuclide has been approved by regulatory authorities in Europe or the United States and is commercially available (Sr-89, Sm-153, and Re-186), (3) the dose of radionuclides must be clinically effective, (4) the primary endpoint must be pain, performance status or quality of life, and (5) separate reporting of efficacy should be available for breast cancer patients provided the trial included patients with various types of cancer. The literature search identified 189 individual studies of which 19 trials fulfilled the eligibility criteria. There were three randomized controlled trials of which two trials compared two different radionuclides, and one trial compared two doses of Sm-153. In addition, there were 16 uncontrolled trials. Reporting of trial research methodology in the randomized as well as the uncontrolled trials was low (median Jadad score of 1, range 1–2). Key trial details, such as patient recruitment, description of prior palliative therapies, baseline characteristics, follow up, and reporting of outcome was insufficient in a large proportion of the trials. According to Center of Evidence-based Medicine criteria, there is level 4 documentation for the effect of radionuclides in painful bone metastasis in breast cancer. It has been concluded that there is limited clinical evidence supporting the clinical effect of radionuclides in relieving pain from bone metastasis in breast cancer. Large, randomized controlled trials are needed to establish the utility of bone-seeking radionuclides in the palliative care of breast cancer patients.