Four RCTs that assessed neon beam therapy were included in the review (n=324, range 34 to 166). The process of treatment allocation was described in three studies. Patient characteristics were poorly described in three studies. Intention-to-treat analyses were performed in three studies.
There was a 7% increase in mortality at 12 months with neutron beam therapy compared with photon therapy (RR 1.07, 95% CI 0.95 to 1.20; four studies). This was not statistically significant. Similar results were seen at 24 months. There was no evidence of heterogeneity or publication bias. Two phase I/II studies for carbon and neon ion therapy for glioblastoma reported 10% and 31% two-year overall survival and 13.9 and 19 months median survival.
Three studies reported on toxicity, with complete and permanent epilation in the neutron beam arm compared with scanty or patchy regrowth of finer hair in the photon therapy arm.
Further results were reported in the review.