Radiotherapy for painful bone metastases
Radiotherapy is commonly used to provide pain relief for localised painful bone metastases. It is, however, difficult to provide accurate estimates of the proportion of patients achieving relief, and the extent and duration of relief owing to the variations within the condition and in the primary cancer itself. Contemporaneous interventions and supplementary analgesics further complicate the picture.
McQuay, H. J.; Carroll, D.; Moore, R. A. Radiotherapy for painful bone metastases: a systematic review. Clinical Oncology. 1997; 9: 150-4.
Inclusion criteria were full journal publication; randomised controlled trial of radiotherapy in the palliative treatment of painful bony metastases; radiotherapy schedule; radiotherapy vs. isotope injection; isotope injection vs. placebo; pain outcomes. The nature of the trial designs and illness variations prohibited classic pooling of data, so the review generated best possible quantitative estimates.
Complete pain relief one month after radiotherapy. 27% of patients achieved total pain relief. The NNT was 3.9 (3.5 to 4.4).
50% pain relief one month after radiotherapy. 29% of patients achieved 50% pain relief. The NNT was 3.6 (3.2 to 3.9).
50% pain relief at any time after radiotherapy. 42% of patients achieved 50% pain relief (all schedules), with little difference between the fractionation schedules. Pain relief was similar for the various fractionation schedules adopted, and for single and multiple fraction schedules.
Speed of onset of relief and duration. Based on the largest trial, median duration of complete relief was 12 weeks (759 patients). It took four weeks for half of the patients achieving complete relief to do so.
Radioisotopes and radiotherapy for generalised disease. Based on three trials (192 patients) radioisotopes alone produced a similar degree of relief with a similar onset and duration to that provided by radiotherapy. There were significantly fewer new pain sites in the strontium groups compared with controls. Hemibody irradiation and radioisotopes have the potential to reduce the number of new sites of bone pain, but radioisotopes do have increased haematological toxicity. Radiotherapy plus strontium produced better quality of life scores than radiotherapy plus placebo.
Table: NNTs for various pain relief outcomes with radiotherapy
|Outcome||Data set||Number of patients benefited/total||NNT (95% CI)|
|Complete pain relief one month after radiotherapy||5 trials (all schedules)||368/1373||3.9 ( 3.5 to 4.4)|
|50% pain relief one month after radiotherapy||5 trials (all schedules)||437/1486||3.6 (3.2 to 3.9)|
|50% pain relief at any time after radiotherapy||23 treatment groups (all schedules)||628/1486||not given|
Reviewers state that reporting was poor. There were no obvious differences between the various schedules with nausea and vomiting, diarrhoea or pathological fractures.