Incidence of second neoplasm in childhood cancer survivors treated with GH: an analysis of GeNeSIS and HypoCCS.

OBJECTIVE: Childhood cancer survivors are commonly treated with GH for GH deficiency that develops either as a result of primary malignancy or its treatment. One study--the Childhood Cancer Survivor Study (CCSS)--demonstrated increased risk of second neoplasm (SN) in GH-treated childhood cancer survivors compared with non-GH treated, after adjusting for key risk factors. We assessed the incidence of SN in GH-treated childhood cancer survivors in outpatient observational studies of GH replacement.

DESIGN: Retrospective analysis of two prospective cohort studies that collected data on safety of GH replacement as prescribed in clinical practice.

METHODS: Childhood cancer survivors enrolled in Eli Lilly and Company's pediatric (Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS)) and adult (Hypopituitary Control and Complications Study (HypoCCS)) observational studies of GH treatment were assessed for incidence of SN.

RESULTS: The percentage of childhood cancer survivors treated with GH who developed a SN was 3.8% in pediatric GeNeSIS participants and 6.0% in adult HypoCCS participants. The estimated cumulative incidence of SN at 5 years of follow-up in these studies was 6.2 and 4.8% respectively.

CONCLUSIONS: The incidence of SN in GeNeSIS and HypoCCS GH-treated participants is similar to the published literature and is thus consistent with increased risk of SN in childhood cancer survivors treated with GH. As follow-up times were relatively short (<3 years), longer observation is recommended. Nevertheless, clinicians should be alerted to the possibility of increased risk of SN in childhood cancer survivors treated with GH and continue chronic surveillance.