Intellectual functioning among case-matched cohorts of children treated with proton or photon radiation for standard-risk medulloblastoma

• Authors: Bree Eaton, Emory University; Grace Fong, Emory University; Lisa Ingerski, Emory University; Margaret B Pulsifer, Massachusetts General Hospital; Subir Goyal, Emory University; Chao Zhang, Emory University; Elizabeth A Weyman, Massachusetts General Hospital; Natia Esiashvili, Emory University; James Klosky, Emory University; Tobey MacDonald, Emory University; David H Ebb, Massachusetts General Hospital; Shannon M MacDonald, Emory University; Nancy J Tarbell, Emory University; Torunn Yock, Emory University
• Journal Title: CANCER
• Volume: Volume 127, Number 20
• Publisher: WILEY | 2021-07-13, Pages 3840-3846
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1002/cncr.33774
• Subjects: Health Sciences, Oncology; Biology, Biostatistics; Health Sciences, Mental Health
• Keywords: Science & Technology; Life Sciences & Biomedicine; Oncology; intelligence; medulloblastoma; neurocognitive; pediatric; photon; proton; radiation; BRAIN-TUMORS; THERAPY; SURVIVORS; OUTCOMES; CHEMOTHERAPY; VALIDITY

Abstract

BACKGROUND: Proton therapy may reduce cognitive deficits after radiotherapy among brain tumor survivors, although current data are limited to retrospective comparisons between historical cohorts. The authors compared intelligence quotient scores within a case-matched cohort of children with medulloblastoma treated with proton radiation (PRT) or photon radiation (XRT) over the same time period. METHODS: Among 88 consecutive patients with standard-risk medulloblastoma treated with PRT or XRT at 2 institutions from 2000 to 2009, 50 were matched 1:1 (25 with PRT and 25 with XRT) according to age, gender, date of diagnosis, histology, radiation boost, and craniospinal irradiation dose. One-way analyses of variance were performed to compare the Full-Scale Intelligence Quotient (FSIQ) and associated index scores between the 2 cohorts. RESULTS: Neurocognitive data were available for 37 survivors (17 with PRT and 20 with XRT) from the matched cohort. The mean age was 8.5 years (SD, 4.14 years). The median follow-up was 5.3 years (range, 1.0-11.4 years) and 4.6 years (range, 1.1-11.2 years) for the PRT and XRT cohorts, respectively (P =.193). Patients treated with PRT had significantly higher mean FSIQ (99.6 vs 86.2; P =.021), verbal (105.2 vs 88.6; P =.010), and nonverbal scores (103.1 vs 88.9; P =.011) than the XRT-treated cohort. Differences in processing speed (82.9 vs 77.2; P =.331) and working memory (97.0 vs 92.7; P =.388) were not statistically significant. CONCLUSIONS: Radiotherapy-associated cognitive effects appear to be more attenuated after proton therapy. Comprehensive prospective studies are needed to appropriately evaluate the neurocognitive advantages of proton therapy.