The Effect of Proton Radiation Therapy on Thyroid Function in the Treatment of Pediatric Medulloblastoma.
Muhrer, Eli J.
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CitationMuhrer, Eli J. 2016. The Effect of Proton Radiation Therapy on Thyroid Function in the Treatment of Pediatric Medulloblastoma.. Doctoral dissertation, Harvard Medical School.
AbstractPurpose: To investigate the development of hypothyroidism in this population over time and its relationship to the amount of scatter dose to the thyroid, pituitary, and hypothalamus.
Methods: A retrospective chart review of patients diagnosed with medulloblastoma between the years 2003 and 2010 at Dana Farber-Cancer Institute/Boston Children’s Hospital. Subjects included in the analysis received both CSI and radiation therapy (RT) boost to the tumor by proton therapy. Patients were classified as being euthyroid or having primary, compensated, or central hypothyroidism.
Results: 24 fit criteria for analysis. Incidence of hypothyroidism of all forms was 8/24 (33%). There were no cases of primary hypothyroidism. The incidence of compensated hypothyroidism was 5/24 (21%) and of central hypothyroidism was 3/24 (12.5%). For compensated hypothyroidism, mean time to diagnosis from initiation of RT was 2.30 years (range 1.44 to 3.38). Comparing compensated hypothyroidism vs. euthyroidism, mean age at initiation of RT, 5% thyroid dose, 50% thyroid dose, 90% thyroid dose, and CSI dose were not significant. Mean pituitary dosing was significantly higher in those with central hypothyroidism versus all other patients (p=0.0001)
Conclusions: Despite minimal radiation to the thyroid gland, hypothyroidism is a sequelae in pediatric patients with medulloblastoma who receive proton RT. The current analysis shows no predictor of who develops compensated hypothyroidism (thyroid injury). Higher dose pituitary radiation was associated with increased central hypothyroidism, which could have masked primary or compensated hypothyroidism.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:40620263