Palliative fractionated radiotherapy for bone metastases clinical and biological assessment of single versus multiple fractions.

BACKGROUND Radiotherapy is effective in controlling pain from bone metastases which is a direct result of bone resorption. The urine resorption marker DPD proved important in assessing effectiveness of palliative radiotherapy to bone metastases. There is still controversy about the optimum adopted fractionation regimen. The aim of this study is to compare single fraction 8Gy with the standard treatment course of 30Gy/10 fractions/ 2weeks and to a third regimen of 20Gy/5 fractions/ 1week regarding factors impacting on QoL in terms of improved pain, mobility, analgesia scores, PS. The decrease of urine DPD was included as an objective parameter of response. PATIENTS AND METHODS A prospective phase lll controlled study of palliative radiotherapy was conducted on 60 patients with bone metastases from known primary sites divided into 3 groups each of 20 patients balanced in age, sex, and type of malignancy, to be treated with one of three RT regimens. Assessment was done before and 6 weeks after treatment completion according to an established scoring system. RESULTS Pain and analgesia scores were improved in the group receiving 30Gy/10 fr. regimen (p = 0.002 = 0.003) with no significant improvement of mobility (p=0.16) or PS (p=0.08). Urine DPD was decreased in this group by 43% in 9/20 patients. The group receiving single fraction of 8 Gy showed a significant improvement of scores of pain (p=0.008), analgesia (p=0.01), mobility (p=0.001), PS (p=0.01) and decrease in urine DPD by 33% in 7/20 patients. The group receiving 20Gy/5 fr. protocol achieved improved scores of pain (p=0.002), analgesia (p=0.008), mobility (p=0.03), and a decrease of ,-DPD by 56% in13/20 patients which was significantly better than the group receiving single 8Gy fraction,(p=0.03). There was a trend towards an increased number of reirradiations in patients receiving single fraction 8Gy, though not significant, whereas reirradiation was significantly correlated with the high initial ,-DPD level within all groups. CONCLUSION The 20Gy/5fr. regimen seems to be superior to both the standard 30Gy/10fr. and the single fraction 8Gy as it achieved significant improvement of three clinical criteria, pain, analgesia and mobility concomitantly with significant decrease in urine DPD. Urine resorption markers confer subjective evaluation of radiotherapy response in patients with bone metastases. The high initial ,-DPD level was significantly correlated with the need to reirradiation. Key Words: Fractionated radiotherapy , Bone metastases , Bone resorption markers.