Objective: To explore the ideal fractionated regimen of radiotherapy applied in malignant tumor with bone metastases. Methods: 165 patients with bone metastases were admitted in our department from May 1996 to Dectember 2000 and answered to the inclusive criteria. According to the different radiotherapeutic fractionation regimen

they were divided into three groups: Group I (conventional fractionation)

Group II (large fractionation) and Group III (larger fractionation). Their different efficacy

bone pain score

initial time of effect and relieved degree of bone pain were compared respectively. Results: The total response rate of radiotherapy applied in malignant tumor with bone metastases is 94.5%

the striking response rate is 77.0%

and there is statistical diversity in striking response rate between Group III and Group I (P<0.05); of the three groups

there is statistical difference in terms of the bone pain score before and after radiotherapy (Group I and Group II

P<0.05; Group III P<0.01); comparing Group III with Group I and Group III with Group II

there is striking diversity in the initial time of effect (P<0.01

<0.05

respectively). As far as the initial time of effect

bone pain score and relieved degree of bone pain and so on

the larger fractionation group (Group III) are superior to the other groups. Conclusion: Larger fractionation regimen is the ideal approach of radiotherapy applied in malignant tumor with bone metastases.