Evaluation of four fractionation schedules of radiation therapy in re-irradiation of painful bone metastases.

Background:- Palliative radiotherapy has proven to be successful in treating pain caused by metastatic lesions in any bone. In most prospective randomized trials on radiotherapy for bone pain, responses up to 70% were reported. However, when survival was prolonged, recurrent pain was reported in up to 50% of patients. It is to be expected for the future, since patients are living longer with disseminated disease, that symptoms may recur & therefore retreatment of bone metastases for palliative reasons will increase. The aim of the study:- Is to evaluate the efficacy and safety of re-irradiation for painful bone metastasis comparing different fractionation regimens with an assessment of subjective response & toxicity. Patient and methods:-one hundred and twenty patients with bone metastasis or bone pain with previous irradiation were included in this prospective randomized study comparing 8 and 6 Gy single fraction with multiple fractions 3 Gy in 10 fractions and 4 Gy in 5 fractions. The primary end point of treatment was the relief of pain, improvement of quality of life. However, the secondary end point was comparing the short term side effects of these treatment regimens. The results:- pain response: after 2 weeks, complete response was observed in 23.3% in group I, 13.3% in group II, III & 20% in group IV and partial response in 66.7% in group I, 73.3% in group II, 76.7% in group III & 70% in group IV. After 4 weeks, complete response was observed in 23.3%, in group I, III & IV while 16.7% only in group II and partial response in 70 % in group I, IV & and 73.3% in group II, III. After 8 weeks as shown in table 4, complete response was observed in 26.7% in group I, 23.3% in group II, 33.3% in group III & 30% in group IV and partial response in 70% in the group I&II, 63.3% in group III & 66.7 % in group IV. no significant difference in pain response was observed between the four groups. Analgesic requirement after 8 weeks of radiotherapy: patients that complained of pain that required strong narcotic decreased in group I: from 10 to 5, group II: from 13 to 6, group III: from 13 to 5, group IV: from 12 to 6. Patients with karnofsky p.s. 90-100 increased from 0 to 1 in all groups while patients of karnofsky p.s. 70-80 increased from 8 to 23 and from 10 to 22, from 12 to 25 and from 9 to 22 in group I, II, III and IV respectively. Evaluation of acute toxicity: treatment was tolerated in all groups, as, grade I diarrhea occur only in 1 patient in group I and II & dermatitis occur in 3 patients, 1 in each group I, II, and III . Conclusion:- the results of our study seem to confirm that there no significant difference between the four regimens of dose fractionation of external beam radiotherapy (8 Gy single fraction, 6 Gy single fraction ,30 Gy in ten fractions and 20 Gy in five fractions) in palliative treatment of bone metastasis as regard pain relief so the use of 8 Gy single fraction of radiotherapy may be of benefit for the patient by reducing treatment time and cost also reducing the treatment burden for hospital, stuff and equipment.