Background

Hypothalamic-pituitary (HP) dysfunction after craniospinal irradiation (CSI) is frequently observed in childhood brain tumor survivors (CBTS). The risk increases with higher dose and younger age at time of radiation exposure

Aim

To quantify radiological alterations of the HP-region in time in CBTS after CSI and to correlate these alterations to occurrence of HP dysfunction

Methods

Ninety survivors of childhood medulloblastoma from a previously reported nationwide cohort, treated with CSI between 2002-2012, were included. Sixty CBTS (67%) were diagnosed with HP dysfunction during follow-up (FU). MRI scans were collected from time of diagnosis, post-neurosurgery, post-radiation, 3 and 5 years of FU. Pituitary height (PH) and width (PW) were measured on sagittal images. The pituitary stalk (PS) width was assessed by measuring the ratio of the PS to basilar artery (BA) on axial images. Volume measurements of the PG (PGV) were performed. Observers were blinded for outcome of HP function. Separate analyses were performed for children < 6 years at time of CSI. All measurements were corrected for age and gender using Z-scores. Statistical analyses were performed by SPSS

Results

Mean PH (p<0.01, 95% CI [0.25, 1.27], PW (p<0.01, 95% CI [0.85-2.32], width of PS (p<0.01, 95% CI [0.38-3.0] and PGV (p<0.05, 95% CI [0.12-1.29] declined during FU. No correlation was observed between radiological alterations in time and presence of HP dysfunction. A small interaction effect was seen for PS/BA ratio and presence of HP dysfunction (p=0.97, F=2.44). HP dysfunction occurred more frequently in CBTS treated with CSI < 6 years (71% vs 58%). Radiological alterations in this age group also could not be related to presence of HP dysfunction

Conclusion

CBTS treated with CSI show radiological alterations of the HP region in time. Exposure to cranial irradiation in childhood has a negative effect on PH, PW, width of PS and PGV. These effects cannot be related to development of HP dysfunction or age at time of CRT. Prospective studies are needed to confirm these results