Dosimetric Impacts on Height Development after Radiotherapy for Intracranial Non-germinomatous Germ Cell Tumours

Abstract Objectives Intracranial non-germinomatous germ cell tumours (NGGCTs) are rare pediatric central nervous system (CNS) tumours. Growth impairment induced by radiation treatment was rarely evaluated. We aimed to study the impacts of radiotherapy on height development as well as the dosimetric constraints, providing potential insights for hormonal treatment. Methods A total of 148 pediatric patients diagnosed with NGGCTs were retrospectively studied. Sex, age at irradiation, physical doses and biologically effective dose (BED), height and endocrine status were obtained for analysis. The cumulative change in height was assessed using age-matched normalized height (ANH). Cumulative physical doses and BEDs for the whole brain and pituitary were derived via dose-volume histograms (DVHs) and BED-volume histograms (BEDVHs). Results In contrast to patients > 11.5 year., linear correlations between ANH and cumulative physical doses as well as BEDs to the whole brain and pituitary were identified in patients ≤ 11.5 year. Dosimetric constraints to the pituitary was 36 Gy for physical dose (AUC = 0.70 [95% CI, 0.54–0.86], P < 0.05) and 63 Gy2 BED (AUC = 0.69 [95% CI, 0.53–0.86], P < 0.05). Impaired hormone secretion in terms of GH and TSH were observed following cranial irradiation (both P < 0.001), particularly for those with tumours at the suprasellar region (GH: P < 0.01, TSH: P < 0.001). In contrast to patients > 11.5 year., the ANH for patients with tumours in the suprasellar region was significantly lower than those in the other locations (P < 0.01). Conclusions Our study revealed the impacts of cumulative doses and tumour locations for radiation-associated growth impairment. Reduced levels of GH and TSH were observed in patients ≤ 11.5 year. with tumours particularly in the suprasellar region.