Bone metastasis: review and critical analysis of random allocation trials of local field treatment

Compare and contrast reports of random allocation clinical trials of local field radiation therapy of metastases to bone to determine the techniques producing the best results (frequency, magnitude, and duration of benefit), and relate these to the goals of complete relief of pain and prevention of disability for the remaining life of the patient.

Review all published reports of random allocation clinical trials, and perform a systematic analysis of the processes and outcomes of the several trial reports.

All trials were performed on selected populations of patients with symptomatic metastases and most studies included widely diverse groups with regard to: (a) site of primary tumor, (b) location, extent, size, and nature of metastases, (c) duration of survival after treatment All trial reports lack sufficient detail for full and complete analysis. Much collected information is not now available for reanalysis and many important data sets were apparently never collected. Several of the variations in patient and tumor characteristics were found to be much more important than treatment dose in the outcome results. Treatment planning and delivery techniques were unsophisticated and probably resulted in a systematic delivery of less than the assigned dose to some metastases. In general the use and benefit of retreatment was greater in those patients who initially received lower doses but the basis and dose of retreatment was not documented. Follow-up of patients was varied with a large proportion of surviving patients lost to follow-up in several studies. The greatest difference in the reports is the method of calculation of results. The applicability of Kaplan-Meier actuarial analysis, censoring the lost and dead patients, as used in studies with loss to follow-up of a large number of patients is questionable. The censoring involved is "informative" (the processes of loss relate to the outcome) and not acceptable since it results in artificial elevation of the frequency of response. Overall, higher dose fractionated treatment regimens produced a better frequency, magnitude, and duration of response than lower dose single-fraction regimens. Relapse after initial response was frequent. The "median duration of relief" was much shorter than the "median duration of survival" post-treatment. Thus the "net pain relief" is far less than the goal of pain relief for the total duration of life after treatment.

The pain relief obtained in all studies is poor and our care practices need to be improved. Many patients never achieved complete relief and for most who did, the duration of relief was much less than their period of survival after treatment. Higher dose, fractionated treatments produced a greater frequency, magnitude, and duration of response with an improved "net pain relief." Additional trials with selection of comparable cases, good definition of extent of disease, exemplary treatment, and complete follow-up are required.