This study from Sweden compared acute side effects of protons (n = 37) and photons (n = 59) for pediatric medulloblastoma. No significant difference was demonstrated in incidence or severity of fatigue, headache, nausea, dermatitis or gastrointestinal toxicity during treatment. Incidence of grade 2 nausea (24.3% vs. 25.4%) and grade 3 nausea (18.9% vs. 16.9%) was similar in the proton and photon group (p = 0.71). Incidence of grade 2 headache (2.7% vs. 3.4%) was also comparable between groups (p = 0.6). 

Median percentual weight loss during treatment was − 4.66% in the photon cohort and − 1.9% in the proton group resulting in a borderline significant difference in percentual weight loss between treatment groups (p = 0.09). A significant difference in brainstem dose was observed between treatment modalities (photons 52.9 Gy vs. protons 49.3 Gy, p = 0.007), however the result did not correlate with lower incidence of nausea in the proton group. Median percentual reduction (0% vs. -11,25%) in hemoglobin was significantly smaller during proton-RT (p < 0.001). No difference was observed for leucocytes, neutrophiles, or platelets. 

The authors concluded that proton radiotherapy is safe and well tolerated treatment. However, the most benefit from proton radiotherapy is expected years after treatment on development of late complications.