Background: Growth hormone deficiency (GHD) is the commonest hypothalamic-pituitary (HP) disorder in cancer survivors. The only few studies in literature addressing GH efficacy in a large cohort of patients concluded that, though improving height outcome, GH therapy may not entirely restore final height (FH) potential according to mid-parental height (MPH). Thus, in order to optimize outcome, more information on factors influencing growth response in these children is needed.
Design and Methods: This was a retrospective study on final height in 87 children (M=54) who received GH (first 2 years mean dose 0.026±0.006mg/kg/day) for GHD secondary to tumours treated with cranial radiotherapy (Rx) (GroupA,n=40), craniospinal Rx (n=23) and total body Rx (n=16) (GroupB,n=39) or tumours involving HP area who didn't received Rx (GroupC,n=8). 19/87 patients with central precocious/early puberty also received GnRH analogs (GnRHa). In 45/87 patients MPH was retrieved (20 GroupA; 25 GroupB). We evaluated GH efficacy as 1st and 2nd year response, FH and height loss (HL) at FH (ΔFH-MPH SDS) and the contribution of several independent variables to FH and HL.
Results: Patients showed an overall good response during the 1st and 2nd year of therapy (HT gain 0.38±0.35SDS and 0.18±0.30SDS, P<0.0001, respectively), with a mean FH in the normal range (-0.85±1.34SDS) though not significantly different from HT SDS at GH start (-0.88±1.17SDS). 15/87 had a FH<-2SDS and this was more frequently encountered in GroupB (11/15,P=0.006). 67% (30/45) failed to reach their MPH, with a HL at FH of -0.67±1.41SDS (P=0.0027). This was more evident in GroupB, where only 2 children achieved their MPH (P<0.0001). However, HL at FH improved or remained stable compared to baseline in 26/45 patients (58%). At stepwise regression, the most important determinants of FH were HT at baseline and lag time (B=0.91±0.18,P<0.0001 and B=-0.46±0.17,P=0.012, respectively). There was no significative difference in FH among patients treated for CPP/early puberty and the remaining patients (-0.84±1.32SDS vs -0.86±1.35SDS).
Conclusion: Compared to published data, our study showed one of the best results considering both short and long-term outcomes of GH treatment. GH and GnRHa therapy, when indicated, though failed to induce catch-up growth, prevented further height loss, leading to a FH within the normal range but still below MPH, especially in children who received craniospinal or total body Rx. Our study confirmed the importance of early GHD diagnosis and prompt GH replacement.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology