Endocrine Abstracts

Introduction: The combination of chemotherapy with prophylatic cranial radiotherapy (C-RT) allowed the improvement of survival rates of pediatric acute lymphoblastic leukemia (ALL) survivors while putting them at risk of develeping long-term endocrine deficiencies, like growth hormone deficiency (GHD).

Current evidence suggests that the prevalence of GHD in children treated with radiation doses ≥ 30–50 Gy for non-pituitary brain tumors is >50% and 100% in those exposed to the same dose for pituitary brain tumors. However, the prevalence of GHD in the setting of lower doses used for hematological malignancies (18–24 Gy) is not so well characterized.

Our aim was to evaluate our cohort of childhood ALL survivors that developed GHD.

Methods: Retrospective analysis of childhood AAL survivors followed the Late-Effects Clinics of our center between 1980–2019.

Results: We found 324 eligible patients with a mean follow-up of 7.9 ± 6.1 years. The mean age of ALL diagnosis was 6.1 ± 4.1 years. They were all treated with chemotherapy, 235 (72,5%) patients were exposed to C-RT with a median dose of 18 Gy (12–37). Sixty-one (18.8%) patients had hematopoietic cell transplantation, from whom 31 (50%) had total body irradion. We identified 120 cases (37%) of GHD with a mean age at diagnosis of 11,5 ± 4,3 years. Within the 235 irradiated patients of the cohort, we found 113 (49,8%) cases of GHD and this percentage raised to 73.9% when we analysed those who were submitted to insulin-tolerance test (ITT). The mean SDS of IGF-1, stature, growth velocity and bone age at diagnosis were –0.93 ± 1.09, –1.3 ± 1.2, –1.4 ± 1.1 and –0.76 ± 1.5, respectively. Sixty-six of the 120 (55%) patients with GHD were treated with somatropin. From the 50 treated patients in whom was possible to evaluate the final stature, 46 (92%) reached the family target heigh (FTH). This was not true for the non-treated patients with GHD (P = 0,017).

Conclusion: GHD was a common finding in our cohort and C-RT played a major role in its development. Our data show that GHD cases might be underestimated if ITT is not performed since the majority of patients didn´t have a severe IGF-1 deficit nor auxology ≤ 2SDS at diagnosis. We thereby highlight the importance of performing systematic GH stimulation test in irradiated children, given that a timely somatropin reposition allows the achievement of FTH.