Thyroid diseases in patients treated during pre-puberty for medulloblastoma with different radiotherapic protocols

We evaluated thyroid disease in 32 patients treated, during pre-puberty, fo r medulloblastoma, followed for at least 4 years and without relapse during observation. After surgery the patients underwent chemotherapy (CT) and ra diotherapy (RT). The protocols were as follows: 20 patients (group A) SNC 7 6 and SNC 85 protocols which included conventional fractionated RT (36-40 G y to the craniospinal axis and a 14-18 Gy boost to the posterior fossa, adm inistered as 1.5-1.8 Gy per fraction per day) and a junction between the cr anial and the spinal fields at C2-C3 level; 12 patients (group B) SNC 91 pr otocol which included hyperfractionated RT (36 Gy to the craniospinal axis and a 30 Gy boost to the posterior fossa; this was administered as 1 Gy per fraction twice per day) and a junction at levels C5-C6 or C6-C7 level, The mean age at diagnosis was 7.4 +/- 3.2 years for group A and 8.4 +/- 2.6 ye ars for group B. Thyroid function was evaluated yearly and ultrasonographic characteristics every 2 years. The patients were followed for a mean of 10 .8 +/- 3.8 for group A and 6 +/- 1.4 years for group B. Primary hypothyroid ism was diagnosed in 16 group A patients and 4 group B patients, and centra l hypothyroidism was diagnosed in 2 group A patients (difference in risk of developing hypothyroidism evaluated with a Wilcoxon-test: p = 0.048). Ultr asonography showed reduced thyroid volume in 7 group A cases, and structura l changes in 21 patients (17 group A, 4 group B); 9 L-thyroxine-treated pat ients were confirmed hypothyroid after having stopped therapy. A thyroid no dule was detected in two cases (one from each group). In conclusion, our da ta indicate that thyroid injury may be diminished by the use of hyperfracti onation and low-junction radiotherapy in the treatment of medulloblastoma. (J. Endocrinol. Invest. 24: 387-392, 2001) (C) 2001, Editrice Kurtis.