Different Fractionation in Whole Brain Irradiation for Multiple Brain Metastases

Background: this study compared the efficacy of two commonly used fractionationschedules for palliative whole brain irradiation in patients with brain metastases, andassessed the association of the radiotherapy therapy oncology group (rtog)recursive partitioning analysis for brain metastases (rpa) to survival with eachschedule.methods: patients with multiple (more than three) brain metastases were assignedto receive whole brain irradiation in 20 gy over 5 fractions (group 1) or 30 gy over10 fractions (group 2). primary outcome was response and overall survival in each group.secondary outcome was the rpa classification relation to overall survival and its possiblerole in the choice between schedules.results: there were 54 patients in group 1 and 39 in group 2. there was nosignificant difference in response (p=0.67) or overall survival between the two groups(p=0.55). however rpa 1 patients had significantly better overall survival than rpa2 patients in both group 1 (p=0.02) and group 2 (p=0.0014), but no significantdifference was found when overall survival of rpa 1 patients of both groups werecompared (p=0.47) or that of rpa 2 patients in both groups (p=0.29).conclusion: the two schedules assessed are comparable in terms of response andoverall survival. rpa 1 patients have better overall survival than rpa 2 patientsregardless of the fractionation used. a schedule of 20 gy over 5 fractions should beroutinely considered for rpa 2 patients as they are less likely to experience latetoxicity. this schedule may be considered for rpa 1 patients, however larger randomizedtrials are needed to confirm the results and assess differences in neurocognitivefunction.