Endocrine Abstracts

Final height outcome is important in survivors of childhood brain tumours. Growth hormone replacement is indicated in those found to be GH deficient (GHD). More recently, GnRH analogues (GnRHa) have been introduced to delay early or rapidly progressing puberty. Studies to final height are important to determine the effectiveness of growth promoting strategies.

SUBJECTS & METHODS Final height results in children receiving GH replacement for radiation induced GHD from 1992-2002 have been compared with a similar audit performed at the same unit from 1975-1991. 33 children were identified and their growth data compared with data obtained in 24 children from the previous audit. All had received a combination of cranial or craniospinal irradiation with or without chemotherapy for a brain tumour distant from the hypothalamic pituitary axis.

RESULTS Height loss (cm) (= midparental height - final height (mean +/-SD (n)) has decreased in each treatment group:- cranial irradiation 7.2+/-6.7 (6) vs 3.9+/-8.7 (9) (1975-1991vs1992-2002) (p-ns); cranial irradiation & chemotherapy 18.4+/-3.5 (3) vs 11.4+/-14.7 (3) (p-ns); craniospinal irradiation 17.0+/-5.9 (9) vs 11.8+/-4.2 (12) (p<0.02); craniospinal irradiation & chemotherapy 24.5+/-11.1 (6) vs 15.3+/-7.1 (9) (p<0.05). The mean time between irradiation and starting GH therapy was 4.38+/-2.09 vs 3.09+/-1.41 years (1975-1991vs1992-2002) (p<0.005). GnRHa was used in 11 of the 33 patients reaching final height between 1992 and 2002 but none in the initial audit. The onset of puberty was 11.4+/-0.4 (no GnRHa;n=22) vs 8.63+/-0.8 years (GnRHa;n=11) (p<0.005). The mean difference between target and actual final height was 11.9cm without GnRHa vs 7.5cm with GnRHa.

CONCLUSIONS We have demonstrated an improvement in final height in children with GHD following therapy for brain tumours over the last 25 years. This may reflect:- 1) the use of more standardised synthetic GH schedules and better dosing regimes, 2) a reduction in time between finishing radiotherapy and receiving GH replacement, and 3) the use of GnRHa in those children in whom growth is adversely affected by early puberty.