The effect of a single fraction compared to multiple fractions on painful bone metastases: a global analysis of the Dutch Bone Metastasis Study

Purpose: To answer the question whether a single fraction of radiotherapy t hat is considered more convenient to the patient is as effective as a dose of multiple fractions for palliation of painful bone metastases. Patients: 1171 patients were randomised to receive either 8 Gy x 1 (n = 585 ) or 4 Gy x 6 (n = 586). The primary tumour was in the breast in 39% of the patients, in the prostate in 23% in the lung in 25% and in other locations in 13%. Bone metastases were located in the spine (30%), pelvis (36%), fem ur (10%), ribs (8%), humerus (6%) and other sites (10%). Method: Questionnaires were mailed to collect information on pain, analgesi cs consumption, quality of life and side effects during treatment. The main endpoint was pain measured on a pain scale from 0 (no pain at all) to 10 ( worst imaginable pain). Costs per treatment schedule were estimated. Results: On average, patients participated in the study for 4 months. Media n survival was 7 months. Response was defined as a decrease of at least two points as compared to the initial pain score. The difference in response b etween the two treatment groups proved not significant and stayed well with in the margin of 10%. Overall, 71% experienced a response at some time duri ng the first year. An analysis of repeated measures confirmed that the two treatment schedules were equivalent in terms of palliation. With regard to pain medication, quality of life and side effects no differences between th e two treatment groups were found. The total number of retreatments was 188 (16%). This number was 147 (25%) in the 8 Gy x 1 irradiation group and 41 (7%) in the 4 Gy x 6 group. It was shown that the level of pain was an impo rtant reason to retreat. There were also indications that doctors were more willing to retreat patients in the single fraction group because time to r etreatment was substantially shorter in this group and the preceding pain s core was lower. Unexpectedly, more pathological fractures were observed in the single fraction group, but the absolute percentage was low. In a cost-a nalysis, the costs of the 4 Gy x 6 and the 8 Gy x 1 treatment schedules wer e calculated at 2305 and 1734 Euro respectively. Including the costs of ret reatment reduced this 25% cost difference to only 8%. The saving of radioth erapy capacity, however, was considered the major economic advantage of the single dose schedule. Conclusion: The global analysis of the Dutch study indicates the equality o f a single fraction as compared to a 6 fraction treatment in patients with painful bone metastases provided that 4 times more retreatments are accepte d in the single dose group. This equality is also shown in long term surviv ors. A more detailed analysis of the study is in progress. (C) 1999 Elsevie r Science Ireland Ltd. All rights reserved.