Background and purpose: In the prospectively, randomized Dutch Bone Metastasis Study on the effect of a single fraction of 8 Gy versus 24 Gy in six fractions on painful bone metastases, 28% of the patients survived for more than 1 year. Purpose of the present study was to analyze the palliative effect of radiotherapy in long-term surviving patients, and to identify prognostic factors for survival.
Material and methods: Response rates were compared in all patients surviving>52 weeks. The Cox proportional hazards model stratified by primary tumour was used for multivariate (MV) analyses of prognostic factors for survival.
Results: In 320 patients surviving>52 weeks, responses were 87% after 8 Gy and 85% after 24 Gy (P=0.54). Duration of response and progression rates were similar. For all primary tumours, prognostic factors for survival were a good Karnofsky Performance Score, no visceral metastases, and non-opioid analgesics intake (all factors, MV P<0.001).
Conclusions: Single fraction radiotherapy should be the standard dose schedule for all patients with painful bone metastases, including patients with an expected favourable survival. General prognosticators as the Karnofsky Performance Score and metastatic tumour load are useful in predicting survival.