Radiation Oncology/CSI

McGill; 2006 16330119 -- "A simple technique for craniospinal radiotherapy in the supine position." (Parker WA, Radiother Oncol. 2006 Feb;78(2):217-22. Epub 2005 Dec 5.) Supine position, using CT sim Thyroid Hypothyroidism is one of the earliest late side effects of craniospinal irradiation (CSI), and second most common (after growth hormone disturbances) Prevalence of hypothyroidism is 40-80% after CSI There is also an increased risk of thyroid cancer, possibly with doses as low as 1 Gy Milan; 2007 (1998-2001) 17601681 -- "Thyroid-stimulating hormone suppression for protection against hypothyroidism due to craniospinal irradiation for childhood medulloblastoma/primitive neuroectodermal tumor." (Massimino M, Int J Radiat Oncol Biol Phys. 2007 Oct 1;69(2):404-10. Epub 2007 Jul 2.) Prospective. 37 children with medulloblastoma/PNET. Thyroid function evaluation pre and post treatment. Given L-thyroxine at suppressive doses q3 days, starting 14 day prior CSI till end of treatment. Median F/U 7 years for alive patients Outcome: 8 children adequate TSH suppression, 17 children not. Hypothyroid-free survival rate: adequate TSH suppression 70% vs. not adequate TSH suppression 20% (SS) Conclusion: TSH suppression had a protective effect during CSI