Précis: Efficacy of single fraction RT for palliation of bone metastases appears to be confirmed from this trial along with multiple predecessors.
Palliation on the surface appears to be a simple straightforward concept -- treat the patients? symptoms for comfort measures only. In cancer care, most palliative issues involve addressing neurologic symptoms from brain metastases; bleeding from sites of tumor invasion/destruction of normal tissue, bone pain from invasive or metastatic lesions, etc? Thus, tailoring radiation therapy (RT) for palliation should be straightforward. However, some complexity lies in the daily and total dose of radiation, time course of treatment and the size of the treatment field (treat all known sites of disease versus just the symptomatic areas). More importantly, palliation is all about quality of life. The treatments? ability to improve the patients? quality of life must outweigh the detriment of bringing the patient back and forth for daily RT in what could be the final few months, weeks or days of his or her life.
This report deals with one such aspect of palliative care: RT for bone pain. Different regimens have been proposed as "standard" palliative doses and fractionation schemes. Among the most popular are 8 Gy in 1 fraction, 20 Gy in 5 fractions, 30 Gy in 10 fractions, and 35 Gy in 14 fractions. Randomized trials from Europe have demonstrated that 8 Gy in a single fraction is as effective in subjective pain relief as other multifractionated schedules. However, no long-term data have been published, which was the impetus for this report from a British randomized study (including patients from 2 New Zealand institutions).
? Randomized phase III trial of palliative RT for bone pain:
Arm 1 -- 8 Gy in a single fraction
Arm 2 -- 20 Gy in 5 fractions or 30 Gy in 10 fractions
? Pretreatment and post treatment assessments of pain and analgesic requirements were made using questionnaires and interviews.
? Seven hundred and sixty-one patients were deemed eligible for evaluation (4 others had protocol violations and the population represented 10% of those treated for bone metastasis).
? Most (98%) of the patients treated in arm 2 were treated with 20 Gy in 5 fractions.
? Breast, prostate and lung cancers were the predominant primary tumors, while pelvis/hips, spine and ribs encompassed the great majority of metastatic sites treated.
? Overall survival, time to pain relief, time to complete response and time to first increase in pain were not statistically different between the two arms.
? Time to retreatment was significantly longer in the patients that received multifraction RT. Accordingly, the rate of retreatment was 2 fold higher in the 8 Gy arm.
? The incidence and duration of nausea and vomiting was assessed in patients treated in proximity to the GI tract. There was no significant difference between the two arms.
Efficacy of single fraction RT for palliation of bone metastases appears to be confirmed from this trial along with multiple predecessors. The complete response rates in both arms falls just short of 60%. Durability of response is perhaps better with fractionated RT, however retreatment with another single fraction or multifractionation remains a possibility after a single fraction. The gain of single fraction RT is the improvement in quality life by avoiding multiple daily treatments in a terminal situation.