Long term effect of craniospinal irradiation for medulloblastoma is :

Craniospinal Irradiation Hypothyroidism: One of the earliest late side effects of CSI and 2nd MC (after GH disturbance) Prevelence of hypothyroidism is 40-80% after CSI Significantly increased risk of development of benign thyroid nodules and papillary carcinoma of the thyroid many years later Ref: www.ncbi.nlm.gov/pubmed/9121399