PURPOSE: We compared proton beam therapy (PBT) with intensity modulated 
radiation therapy (IMRT) for pediatric craniopharyngioma in terms of disease 
control, cyst dynamics, and toxicity.
METHODS AND MATERIALS: We reviewed records from 52 children treated with PBT 
(n=21) or IMRT (n=31) at 2 institutions from 1996-2012. Endpoints were overall 
survival (OS), disease control, cyst dynamics, and toxicity.
RESULTS: At 59.6 months' median follow-up (PBT 33 mo vs IMRT 106 mo; P<.001), 
the 3-year outcomes were 96% for OS, 95% for nodular failure-free survival and 
76% for cystic failure-free survival. Neither OS nor disease control differed 
between treatment groups (OS P=.742; nodular failure-free survival P=.546; 
cystic failure-free survival P=.994). During therapy, 40% of patients had cyst 
growth (20% requiring intervention); immediately after therapy, 17 patients 
(33%) had cyst growth (transient in 14), more commonly in the IMRT group (42% vs 
19% PBT; P=.082); and 27% experienced late cyst growth (32% IMRT, 19% PBT; 
P=.353), with intervention required in 40%. Toxicity did not differ between 
groups. On multivariate analysis, cyst growth was related to visual and 
hypothalamic toxicity (P=.009 and .04, respectively). Patients given radiation 
as salvage therapy (for recurrence) rather than adjuvant therapy had higher 
rates of visual and endocrine (P=.017 and .024, respectively) dysfunction.
CONCLUSIONS: Survival and disease-control outcomes were equivalent for PBT and 
IMRT. Cyst growth is common, unpredictable, and should be followed during and 
after therapy, because it contributes to late toxicity. Delaying radiation 
therapy until recurrence may result in worse visual and endocrine function.