Palliative radiotherapy of bone metastases: an evaluation of outcome measures

The objective of this study was to identify and evaluate important patient-based outcomes that are specific to the palliative radiotherapy of bone metastases. We first conducted a literature review to identify and evaluate outcomes that are currently in use. To identify outcomes that are important to patients, in-depth patient interviews were conducted. Finally, issues identified through the interviews were quantified through a prospective survey, in which patients completed a questionnaire prior to commencing radiotherapy and again after 6 weeks. In our literature review, we found that there was no standardized definition of either response to radiotherapy or assessment of pain relief. Pain measurement in many studies was undertaken using very simple measures, which could possibly yield inaccurate results. The vast majority of studies did not include quality of life as an endpoint. The patient interviews and survey showed that chronic pain and associated limitation of movement were the disease symptoms causing the most concern. Having a clear, alert mind and being able in self-care were the aspects of daily living given the highest priority. Sustained pain relief and minimizing the risk of future complications were the main priorities relating to radiotherapy treatment. The practical aspects of treatment (travelling distance, remaining at home and brevity of treatment) were of least importance. This study indicates the complexity of evaluating the outcomes of palliative interventions, and confirms the deficiencies of pain relief as the primary end-point. The patient's quality of life is affected by many factors other than pain (such as limited mobility, reduced performance, side effects and impaired role functioning); hence a wider range of end-points is required. Greater sensitivity is required than in currently used end-points. Concurrent diseases as well as concurrent therapies can make it difficult to attribute effects with precision. Unless such factors are considered in research design, the results may prove unreliable.