Association between growth hormone therapy and mortality, cancer and cardiovascular risk: systematic review and meta-analysis

Prevalence of refractoriness when testing growth hormone levels in children

OBJECTIVE

Late night spontaneous growth hormone (GH) pulses may influence the pituitary GH response to provocation tests. We evaluated GH response during arginine-insulin-tolerance test (AITT) after a GH peak during a short spontaneous nocturnal profile (SSNP) in children with short stature or low growth velocity.

DESIGN

Using SSNP and subsequent AITT, we examined 257 children 4-18 years old (138 (53.7%) males) recruited from three hospitals. Medical records were reviewed retrospectively. Refractory children were defined as a GH peak ≥7 μg/L during SSNP but no GH peak ≥7 μg/L during AITT.

RESULTS

In total, 201/257 children had a GH peak ≥7 μg/L at SSNP and/or AITT. Of these, 21.9% were refractory. The proportion of males (p = 0.033) and body mass index (BMI) standard deviation score (SDS) (p = 0.037) were higher in the refractory group than in children with a GH peak ≥7 μg/L during AITT. The median period between last GH peak ≥7 μg/L during SSNP and GHmax at AITT was 210 (30-390) minutes. The GHmax at AITT occurred 30 min earlier for children without a peak ≥7 μg/L during the SSNP (p = 0.004). The number of refractoriness differed somewhat between the hospitals (p = 0.025).

CONCLUSIONS

Many children with short stature were refractory at testing; among them we found few clinical characteristics. Refractoriness might be influenced by some differences in procedure, but needs to be considered when evaluating GH response in children.

Difficulties in Interpreting IGF-1 Levels in Short Stature Children Born Small for Gestational Age (SGA) Treated with Recombinant Human Growth Hormone (rhGH) Based on Data from Six Clinical Centers in Poland

The assessment of IGF-1 concentrations is one of the parameters used for evaluating response to rhGH treatment. An increase in IGF-1 concentration positively correlates with growth improvement, whereas IGF-1 concentrations significantly above the reference range may increase the risk of possible side effects. The aim of this study was to evaluate the IGF-1 local reference ranges for the rhGH treatment centers concerned and to compare these values with the population reference ranges. A retrospective analysis was conducted on auxological data from 229 SGA patients who received rhGH treatment between 2016 and 2020 at six university clinical centers in Poland. The IGF-1 levels were assessed at baseline, after 12 and 24 months, and compared to the reference ranges provided by the local laboratory and to the population reference ranges. After 12 months, 56 patients (24%) presented IGF-1 values > 97th percentile for the local reference range, whereas only 8 (3.5%) did so using the population reference ranges; p < 0.001. After 24 months of treatment, the values were: 47 (33%) > 97th percentile by local vs. 6 (4.2%) by population standards; p < 0.001. Thirty-nine patients had rhGH dose reduced after 12 months, of whom twelve (25%) had IGF-1 > 97th percentile according to the local reference ranges and five (13%) > 97th percentile for the population. Our data suggest that different methods used to determine IGF-1 concentration and the different IGF-1 reference ranges result in a significant proportion of rhGH-treated children with elevated IGF-1 concentration and experiencing dose reductions, which may negatively affect growth rate.

Growth Hormone Replacement Therapy Seems to Be Safe in Children with Low-Grade Midline Glioma: A Series of 124 Cases with Review of the Literature

There is little scientific evidence regarding the safety of GHRT in LGG, where GH deficiency is common.

PURPOSE

to compare the recurrence rate in children with midline LGG, depending on whether or not they have received GHRT, in order to assess its impact on the risk of tumor recurrence.

METHODS

This bicentric retrospective study included 124 patients under the age of 18 who were diagnosed with a midline low-grade glial tumor between 1998 and 2016. We also reviewed literature on this subject. The main outcome measure was tumor relapse, demonstrated by brain MRI.

RESULTS

There were 17 patients in the GH-supplemented group (14%) and 107 patients in the non-supplemented group (86%). Relapse occurred in 65 patients (45.5%); 7 patients died (4.9%); no deaths occurred in patients receiving GHRT. Two patients developed a second tumor (1.4%), none of which had received GHRT. Relapse concerned 36.4% of patients without GHRT and 52.9% of patients with GHRT. The difference was not statistically significant between the two groups (p = 0.3).

CONCLUSION

GHRT does not lead to a statistically significant increase in risk of relapse for pediatric midline low-grade pediatric glioma in our cohort. Although these results appear reassuring, future natural history or prospective studies should be done to ascertain these findings. Nevertheless, these reassuring data regarding GHRT are in agreement with the data in the current literature.

Increase of serum lipoprotein (a), an adverse effect of growth hormone treatment

A number of reports show that high endogenous, or therapeutic administration of human growth hormone (hGH) cause an increase of serum lipoprotein a, Lp(a). Being thrombogenic Lp(a) is an independent risk factor of atherosclerotic cardiovascular disease (ASCVD). Hence, it is hypothesized that the recently reported association between childhood hGH treatment and cardiovascular morbidity is probably due to the GH effect on Lp(a) synthesis. It is therefore suggested to determine serum Lp(a) levels before and during hGH treatment in children and adults.

Exogenous growth hormone promotes an epithelial-mesenchymal hybrid phenotype in cancerous HeLa cells but not in non-cancerous HEK293 cells

In cancer, the Epithelial to Mesenchymal Transition (EMT) is the process in which epithelial cells acquire mesenchymal features that allow metastasis, and chemotherapy resistance. Growth hormone (GH) has been associated with melanoma, breast, and endometrial cancer progression through an autocrine regulation of EMT. Since exogenous and autocrine expression of GH is known to have different molecular effects, we investigated whether exogenous GH is capable of regulating the EMT of cancer cells. Furthermore, we investigated whether exogenous GH could promote EMT in non-cancerous cells. To study the effect of GH (100 ng/ml) on cancer and non-cancer cells, we used HeLa and HEK293 cell lines, respectively. We evaluated the loss of cell-cell contacts, by cell scattering assay and migration by wound-healing assay. Additionally, we evaluated the morphological changes by phalloidin-staining. Finally, we evaluated the molecular markers E-cadherin and vimentin by flow cytometry. GH enhances cell scattering and the migratory rate and promotes morphological changes such as cell area increase and actin cytoskeleton filaments formation on HeLa cell line. Moreover, we found that GH favors the expression of the mesenchymal protein vimentin, followed by an increase in E-cadherin's epithelial protein expression, characteristics of an epithelial-mesenchymal hybrid phenotype that is associated with metastasis. On HEK293cells, GH promotes morphological changes, including cell area increment and filopodia formation, but not affects scattering, migration, nor EMT markers expression. Our results suggest that exogenous GH might participate in cervical cancer progression favoring a hybrid EMT phenotype but not on non-cancerous HEK293 cells.

The Changing Face of Paediatric Human Growth Hormone Therapy

Human growth hormone (hGH) has been used therapeutically to promote growth in children for over 60 years. Pituitary-extracted hGH has demonstrated positive growth promotion since the early 1960s. In 1985, prion-induced contamination of hGH triggered a global epidemic of Creutzfeldt–Jakob disease that was responsible for its discontinuation. Recombinant hGH immediately replaced pituitary hGH and, being available in large amounts, was used and licenced for therapy in GH-deficient children, followed by approval for non-GH deficient disorders such as Turner syndrome, short stature related to birth size small for gestational age, idiopathic short stature, SHOX deficiency, Prader–Willi syndrome and Noonan syndrome. RhGH therapy was refined by the use of growth prediction models; however, unmet needs, such as the variability in response and non-adherence resulted in the development of long-acting rhGH (LArhGH) molecules, which are currently in clinical trials and have shown non-inferiority in comparison with daily rhGH. It is likely that LArhGH will enter clinical practice in 2022 and 2023 and will need to demonstrate safety in terms of immunogenicity, IGF-1 generation, metabolic status and tolerability of potential injection pain and local reactions.

Approach to the Patient: Safety of Growth Hormone Replacement in Children and Adolescents

The use of recombinant human growth hormone (rhGH) in children and adolescents has expanded since its initial approval to treat patients with severe GH deficiency (GHD) in 1985. rhGH is now approved to treat several conditions associated with poor growth and short stature. Recent studies have raised concerns that treatment during childhood may affect morbidity and mortality in adulthood, with specific controversies over cancer risk and cerebrovascular events. We will review 3 common referrals to a pediatric endocrinology clinic, followed by a summary of short- and long-term effects of rhGH beyond height outcomes. Methods to mitigate risk will be reviewed. Finally, this information will be applied to each clinical case, highlighting differences in counseling and clinical outcomes. rhGH therapy has been used for more than 3 decades. Data are largely reassuring, yet we still have much to learn about pharmaceutical approaches to growth in children and the lifelong effect of treatment.

Association Between Recombinant Growth Hormone Therapy and All-Cause Mortality and Cancer Risk in Childhood: Systematic Review and Meta-Analysis

OBJECTIVES

The safety of recombinant human growth hormone (rhGH) treatment in childhood and the role of rhGH therapy in promoting tumorigenesis and progression have been the subject of debate for decades. We aimed to systematically assess the relationship between rhGH therapy in children and adolescents and clinical outcomes, including all-cause mortality, cancer mortality, cancer incidence, and risk of the second neoplasm.

METHODS

Literature retrieval, study selection, and data extraction were completed independently and in duplicate. Effect-size estimates are expressed as standardized mortality ratios (SMRs), standardized incidence ratio (SIR), and relative risk (RR) with a 95% CI.

RESULTS

Data from 24 articles, involving 254,776 persons, were meta-analyzed. Overall analyses revealed the association of rhGH therapy was not statistically significant with all-cause mortality (SMR = 1.28; 95% CI: 0.58-2.84; P = 0.547; I ² = 99.2%; Tau² = 2.154) and cancer mortality (SMR = 2.59; 95% CI: 0.55-12.09; P = 0.228; I ² = 96.7%; Tau² = 2.361) and also cancer incidence (SIR = 1.54; 95% CI: 0.68-3.47; P = 0.229; I ² = 97.5%; Tau² = 2.287), yet statistical significance was observed for second neoplasm (RR = 1.77; 95% CI: 1.33-2.35; P = 0.001; I ² = 26.7%; Tau² = 0.055). Differences in the geographic region, gender, treatment duration, mean rhGH dose, overall rhGH exposure dose, and initial disease accounted for heterogeneity in the subgroup analyses.

CONCLUSION

Our findings indicate that the rhGH therapy is not related to all-cause mortality and cancer mortality and cancer incidence, yet it seems to trigger a second tumor risk. Future prospective studies are needed to confirm our findings and answer the more challenging question regarding the optimal dose of rhGH therapy in children and adolescents.

Safety of Pediatric rhGH Therapy: An Overview and the Need for Long-Term Surveillance

Growth hormone (GH) therapy dates back to 1958 and, though has shown an excellent safety profile in the short-term, has never ceased to raise concern about potential long-term side effects. In the last decade, a number of observational studies in different cohorts of young adult patients treated with GH during childhood have yielded conflicting results. The attention has mainly focused on three major potential risks associated with GH therapy: cancer, cardio and cerebrovascular diseases and diabetes. This review intends to provide a detailed overview of the main studies reporting long-term safety in subjects treated with rhGH therapy during childhood, highlighting the evidence for or against the risk of cancer, cardio and cerebrovascular diseases and diabetes.

Visceral Obesity and Its Shared Role in Cancer and Cardiovascular Disease: A Scoping Review of the Pathophysiology and Pharmacological Treatments

The association between obesity, cancer and cardiovascular disease (CVD) has been demonstrated in animal and epidemiological studies. However, the specific role of visceral obesity on cancer and CVD remains unclear. Visceral adipose tissue (VAT) is a complex and metabolically active tissue, that can produce different adipokines and hormones, responsible for endocrine-metabolic comorbidities. This review explores the potential mechanisms related to VAT that may also be involved in cancer and CVD. In addition, we discuss the shared pharmacological treatments which may reduce the risk of both diseases. This review highlights that chronic inflammation, molecular aspects, metabolic syndrome, secretion of hormones and adiponectin associated to VAT may have synergistic effects and should be further studied in relation to cancer and CVD. Reductions in abdominal and visceral adiposity improve insulin sensitivity, lipid profile and cytokines, which consequently reduce the risk of CVD and some cancers. Several medications have shown to reduce visceral and/or subcutaneous fat. Further research is needed to investigate the pathophysiological mechanisms by which visceral obesity may cause both cancer and CVD. The role of visceral fat in cancer and CVD is an important area to advance. Public health policies to increase public awareness about VAT's role and ways to manage or prevent it are needed.

Long-term mortality after childhood growth hormone treatment: the SAGhE cohort study

BACKGROUND

Recombinant human growth hormone has been used for more than 30 years and its indications have increased worldwide. There is concern that this treatment might increase mortality, but published data are scarce. We present data from the entire dataset of all eight countries of the Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) consortium, with the aim of studying long-term overall and cause-specific mortality in young adult patients treated with recombinant human growth hormone during childhood and relating this to the underlying diagnosis.

METHODS

This cohort study was done in eight European countries (Belgium, France, Germany, Italy, The Netherlands, Sweden, Switzerland, and the UK). Patients were classified a priori based on pre-treatment perceived mortality risk from their underlying disease and followed up for cause-specific mortality. Person-years at risk of mortality and expected rates from general population data were used to calculate standardised mortality ratios (SMRs).

FINDINGS

The cohort comprised 24 232 patients treated with recombinant human growth hormone during childhood, with more than 400 000 patient-years of follow-up. In low-risk patients with isolated growth hormone deficiency or idiopathic short stature, all-cause mortality was not significantly increased (SMR 1·1, 95% CI 0·9-1·3). In children born small for gestational age, all-cause mortality was significantly increased when analysed for all countries (SMR 1·5, CI 1·1-1·9), but this result was driven by the French subcohort. In patients at moderate or high risk, mortality was increased (SMR 3·8, 3·3-4·4; and 17·1, 15·6-18·7, respectively). Mortality was not associated with mean daily or cumulative doses of recombinant human growth hormone for any of the risk groups. Cause-specific mortality from diseases of the circulatory and haematological systems was increased in all risk groups.

INTERPRETATION

In this cohort, the largest, to our knowledge, with long-term follow-up of patients treated with recombinant human growth hormone during childhood, all-cause mortality was associated with underlying diagnosis. In patients with isolated growth hormone deficiency or idiopathic short stature, recombinant human growth hormone treatment was not associated with increased all-cause mortality. However, mortality from certain causes was increased, emphasising the need for further long-term surveillance.

FUNDING

European Union.

Increases in Bioactive IGF do not Parallel Increases in Total IGF-I During Growth Hormone Treatment of Children Born SGA

BACKGROUND

Some children born small for gestational age (SGA) experience supra-physiological insulin-like growth factor-I (IGF-I) concentrations during GH treatment. However, measurements of total IGF-I concentrations may not reflect the bioactive fraction of IGF-I which reaches the IGF-I receptor at target organs. We examined endogenous IGF-bioactivity using an IGF-I kinase receptor activation (KIRA) assay that measures the ability of IGF-I to activate the IGF-IR in vitro.

AIM

To compare responses of bioactive IGF and total IGF-I concentrations in short GH treated SGA children in the North European Small for Gestational Age Study (NESGAS).

MATERIAL AND METHOD

In NESGAS, short SGA children (n = 101, 61 males) received GH at 67 µg/kg/day for 1 year. IGF-I concentrations were measured by Immulite immunoassay and bioactive IGF by in-house KIRA assay.

RESULTS

Bioactive IGF increased with age in healthy pre-pubertal children (n = 94). SGA children had low-normal bioactive IGF levels at baseline (-0.12 (1.8 SD), increasing significantly after one year of high-dose GH treatment to 1.1 (1.4) SD, P < 0.01. Following high-dose GH, 68% (n = 65) of SGA children had a total IGF-I concentration >2SD (mean IGF-I 2.8 SDS), whereas only 15% (n = 15) had levels of bioactive IGF slightly above normal reference values. At baseline, bioactive IGF (SDS) was significantly correlated to height (SDS) (r = 0.29, P = 0.005), in contrast to IGF-I (SDS) (r = 0.17, P = 0.10). IGF-I (SDS) was inversely correlated to delta height (SDS) after one year of high-dose GH treatment (r = -0.22, P = 0.02).

CONCLUSION

In contrast to total IGF-I concentrations, bioactive IGF stayed within the normal reference ranges for most SGA children during the first year of GH treatment.

The Italian Registry of GH Treatment: electronic Clinical Report Form (e-CRF) and web-based platform for the national database of GH prescriptions

BACKGROUND

In Italy, the utilization and the reimbursement of Growth Hormone (rGH) therapy by the National Health System (Servizio Sanitario Nazionale) are regulated by the "Note #39" included in the "Notes for the use of drugs" by the Italian Medicines Agency (AIFA), which are published in the Official Gazette, thus having the force of law. The "Note #39" establishes the diagnosis for which the reimbursement is granted and confirms the assignment of the national health surveillance on the use of GH therapy to the Italian National Institute of Health, requesting its computerization.

AIM

The aim of this work was to realize a dedicated electronic Clinical Report Form based on the mandatory data requested by the Note #39 and allowing the online reporting of the rGH prescriptions by the regional accredited centers.

RESULTS AND CONCLUSIONS

This interface is at the base of the national database of the Italian Registry of GH Treatment, which allows obtaining and managing correct and complete data to provide public health surveillance on GH therapy, both at national and local levels, necessary for policymakers decisions. In addition, this national database could be a useful instrument for improving knowledge about aspects of this treatment still under discussion.

Risk of cancer in patients treated with recombinant human growth hormone in childhood

Recombinant human growth hormone (GH) has been in use for over 30 years, and its indications have gradually expanded from the classical replacement therapy in GH deficiency (GHD) to pharmacological therapy in patients with normal GH secretion. The insulin-like growth factor-I (IGF-I ) is closely GH dependent and is the effector of GH biological actions in peripheral tissues. Since IGF-I has potent mitogenic and antiapoptotic effects, the use of GH, especially outside GHD, has raised safety concern regarding cancer risk. The results of experimental, epidemiological and observational studies are not univocal and a number of biases and confounders affect the interpretation of data. The aim of this review is to critically review the data linking GH therapy during childhood with cancer risk, highlighting strengths and weaknesses of the available evidence.

Growth Hormone's Links to Cancer

Several components of the GH axis are involved in tumor progression, and GH-induced intracellular signaling has been strongly associated with breast cancer susceptibility in genome-wide association studies. In the general population, high IGF-I levels and low IGF-binding protein-3 levels within the normal range are associated with the development of common malignancies, and components of the GH-IGF signaling system exhibit correlations with clinical, histopathological, and therapeutic parameters in cancer patients. Despite promising findings in preclinical studies, anticancer therapies targeting the GH-IGF signaling system have led to disappointing results in clinical trials. There is substantial evidence for some degree of protection against tumor development in several animal models and in patients with genetic defects associated with GH deficiency or resistance. In contrast, the link between GH excess and cancer risk in acromegaly patients is much less clear, and cancer screening in acromegaly has been a highly controversial issue. Recent studies have shown that increased life expectancy in acromegaly patients who attain normal GH and IGF-I levels is associated with more deaths due to age-related cancers. Replacement GH therapy in GH deficiency hypopituitary adults and short children has been shown to be safe when no other risk factors for malignancy are present. Nevertheless, the use of GH in cancer survivors and in short children with RASopathies, chromosomal breakage syndromes, or DNA-repair disorders should be carefully evaluated owing to an increased risk of recurrence, primary cancer, or second neoplasia in these individuals.

GH Supplementation Effects on Cardiovascular Risk in GH Deficient Adult Patients: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

The current meta-analysis aims at evaluating whether the existing clinical evidence may ascertain the effects of growth hormone (GH) replacement therapy on cardiovascular risk, both in isolated GH deficiency (GHD) and in compensated panhypopituitarism including GH deficit.

METHODS

Original articles published from 1991 to 2015 were searched on Medline (Pubmed). Among an overall number of 181 potentially suitable studies, 24 fulfilled the selection criteria and were included in the analysis. Data aggregation was carried out through the calculation of the absolute risk reduction. The meta-analysis was then conducted by means of a fixed-effects model, according to the heterogeneity test (Chi-square statistic).

RESULTS

Fat-free mass (FFM) increase and fat mass (FM) reduction were found, together with a C-LDL reduction, a wide variation in glycaemia and a neutral effect on glycated haemoglobin (HbA1c) and blood pressure. These effects were valid both for isolated GHD patients and for those with compensated panhypopituitarism. The global outcome D showed a nonsignificant reduction of the overall cardiovascular risk (0.53; 95% C.I. -1.23, 2.85).

CONCLUSION

Our meta-analysis shows no signnificatly positive trend in cardiovascular risk after both short and long-term GH supplementation therapy in adult GHD patients. However, a reduction of LDL cholesterol levels has been found. No differences were found between isolated GHD participants and those affected by panhypopituitarism well compensated since at least 3 months.

Circulating IGF-I, IGFBP-3 and the IGF-I/IGFBP-3 Molar Ratio Concentration and Height Outcome in Prepubertal Short Children on rhGH Treatment over Two Years of Therapy

OBJECTIVE

To investigate the occurrence of abnormally elevated values of biomarkers of growth hormone (GH) action in short children on recombinant human GH (rhGH) therapy.

METHODS

Sixty-three prepubertal short children were examined: 31 with GH deficiency (GHD), 25 small for gestational age (SGA), and 9 with Turner syndrome (TS). The main outcomes were the following: standard deviation score (SDS) values of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 molar ratio before, at the 1st and at the 2nd year on rhGH and Δheight (Ht)-SDS to evaluate GH treatment efficacy (adequate 1st-year ΔHt SDS: >0.4 SDS for GHD and >0.3 SDS for non-GHD).

RESULTS

Seventy-eight percent of GHD, 78% of SGA and 55% of TS children had adequate 1st-year ΔHt SDS. In GHD, 88% of IGF-I SDS and IGFBP-3 SDS that were ≤-2.0 SDS at baseline normalized on treatment. Abnormal IGF-I values >+2.0 SDS were observed in 52% of SGA and in 55% of TS patients on rhGH. Within each group, the IGF-I/IGFBP-3 molar ratio increased significantly from pretreatment and throughout therapy, remaining within normal range for most patients. ΔIGF-I/IGFBP-3 molar ratio SDS were significantly higher in children with an adequate response (p < 0.01).

CONCLUSION

Non-GHD groups presented markedly elevated concentrations of GH biomarkers on rhGH and normal IGF-I/IGFBP-3 molar ratio in most patients. Since there is a lack of consensus regarding the molar ratio usefulness, we think that interventions towards a more physiological IGF-I serum profile should be implemented.

Increased risk of bone tumors after growth hormone treatment in childhood: A population-based cohort study in France

The association between growth hormone (GH) treatment and cancer risk has not been thoroughly evaluated and there are questions about any increased risk of bone tumors. We examined cancer risk and especially bone tumor risk in a population-based cohort study of 6874 patients treated with recombinant GH in France for isolated GH deficiency, short stature associated with low birth weight or length or idiopathic short stature. Adult mortality and morbidity data obtained from national databases and from questionnaires. Case ascertainment completeness was estimated with capture-recapture methods. Standardized mortality and incidence ratios were calculated using national reference data. 111 875 person-years of observation were analyzed and patients were followed for an average of 17.4 ± 5.3 years to a mean age of 28.4 ± 6.2 years. For cancer overall, mortality and incidence were not different from expected figures. Five patients developed bone tumors (chondrosarcoma, 1, Ewing sarcoma, 1, osteosarcoma, 3) of whom 3 died (Ewing sarcoma, 1, osteosarcoma, 2), whereas only 1.4 case and 0.6 deaths were expected: standardized mortality ratio, 5.0 and standardized incidence ratio from 3.5 to 3.8 accounting or not accounting for missed cases. Most patients received conventional doses of GH, although one patient with osteosarcoma had received high dose GH (60 μg/kg/d). This study confirms an increased risk of bone tumors but not overall cancer risk in subjects treated with GH in childhood for isolated GH deficiency or childhood short stature. Further work is needed to elucidate the mechanisms involved.

Growth hormone - past, present and future

Growth hormone (GH) research and its clinical application for the treatment of growth disorders span more than a century. During the first half of the 20th century, clinical observations and anatomical and biochemical studies formed the basis of the understanding of the structure of GH and its various metabolic effects in animals. The following period (1958-1985), during which pituitary-derived human GH was used, generated a wealth of information on the regulation and physiological role of GH - in conjunction with insulin-like growth factors (IGFs) - and its use in children with GH deficiency (GHD). The following era (1985 to present) of molecular genetics, recombinant technology and the generation of genetically modified biological systems has expanded our understanding of the regulation and role of the GH-IGF axis. Today, recombinant human GH is used for the treatment of GHD and various conditions of non-GHD short stature and catabolic states; however, safety concerns still accompany this therapeutic approach. In the future, new therapeutics based on various components of the GH-IGF axis might be developed to further improve the treatment of such disorders. In this Review, we describe the history of GH research and clinical use with a particular focus on disorders in childhood.

Long-term safety of growth hormone-A combined registry analysis

OBJECTIVES

Preliminary data from the French cohort of the Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) study raised concerns regarding the safety of recombinant human GH, suggesting that GH may increase mortality and incidence of stroke in patients treated during childhood for GH deficiency or short stature. We evaluated published safety data, focusing on mortality, neoplasms, cerebrovascular events and diabetes across a number of large-scale pharmaceutical company GH registries.

DESIGN

A literature review was conducted using PubMed, EMBASE and Google Scholar to identify all relevant safety data from manufacturers' GH registries published between 1988 and April 2016. Results were hand-sorted to exclude nonrelevant publications; bibliographic references from retrieved articles were evaluated for any additional references.

RESULTS

The published data do not support an increased risk of mortality in children or adults treated with GH. There was no evidence of an increased risk of stroke, new malignancy, leukaemia, nonleukaemic extracranial tumours or recurrence of intracranial malignancy in patients without risk factors. The risk of a second neoplasm is increased, particularly if patients have received radiation therapy for a central nervous system tumour. There may be an increased risk of type 2 diabetes in GH-treated patients, but this appears to be confined to those with pre-existing risk factors.

CONCLUSIONS

Patients with risk factors for malignancy or type 2 diabetes should be treated with caution and monitored during follow-up, but current published data provide reassurance on the long-term safety profile of GH in patients receiving GH treatment.

Cancer Risks in Patients Treated With Growth Hormone in Childhood: The SAGhE European Cohort Study

CONTEXT

Growth hormone (GH) is prescribed for an increasing range of indications, but there has been concern that it might raise cancer risk. Published data are limited.

OBJECTIVE

To examine cancer risks in relation to GH treatment.

DESIGN

Cohort study.

SETTING

Population-based.

PATIENTS

Cohort of 23,984 patients treated with recombinant human GH (r-hGH) in eight European countries since this treatment was first used in 1984. Cancer expectations from country-specific national population statistics.

MAIN OUTCOME MEASURES

Cancer incidence and cancer mortality.

RESULTS

Incidence and mortality risks in the cohort were raised for several cancer sites, largely consequent on second primary malignancies in patients given r-hGH after cancer treatment. There was no clear raised risk in patients with growth failure without other major disease. Only for bone and bladder cancers was incidence significantly raised in GH-treated patients without previous cancer. Cancer risk was unrelated to duration or cumulative dose of r-hGH treatment, but for patients treated after previous cancer, cancer mortality risk increased significantly with increasing daily r-hGH dose (P trend < 0.001). Hodgkin lymphoma (HL) incidence increased significantly with longer follow-up (P trend = 0.001 for patients overall and 0.002 for patients without previous cancer).

CONCLUSIONS

Our results do not generally support a carcinogenic effect of r-hGH, but the unexplained trend in cancer mortality risk in relation to GH dose in patients with previous cancer, and the indication of possible effects on bone cancer, bladder cancer, and HL risks, need further investigation.

GH deficiency in adult survivors of childhood cancer

Childhood cancer survivors (CCS) are a fast growing population, but late adverse effects of cancer therapies are not rare. In CCS treated with cranial radiotherapy, growth hormone deficiency (GHD) is a well-known occurrence and the potential impact of GH replacement therapy on the global outcome of CCS is under continuous evaluation. In the present review, we discuss advantages and disadvantages of GH replacement therapy in survivors of pediatric malignancies, taking into consideration the different reasons for treating GHD during childhood or adult life. It is doubtless that GH treatment is advisable to obtain a normal growth in pediatric patients. As far as the beginning/continuation of the replacement therapy in adult age is concerned, contrasting results have been reported in literature. The suggestion is that the decision to treat adult CCS should be taken after careful evaluation of each patient's clinical history and of the potential side effects, in agreement with the patients.

Mortality and cancer incidence among patients treated with recombinant growth hormone during childhood in Israel

CONTEXT

The inconclusive evidence regarding long-term safety of recombinant human growth hormone (rhGH) therapy underlines the need for long-term large-scale cohorts.

OBJECTIVE

To assess long-term mortality and cancer incidence among patients treated with rhGH during childhood in Israel.

DESIGN

A population-based cohort study.

SETTING

Data were retrieved from a national register established in 1988. Mortality data from the national population register were available through 31 December 2014. Data on cancer incidence from the national cancer registry were available through 31 December 2012.

PARTICIPANTS

All patients ≤19 years approved for rhGH treatment during 1988-2009 were included. Patients were assigned to three risk categories, according to the underlying condition leading to growth disorder.

MAIN OUTCOME MEASURES

All-cause mortality and cancer incidence rates were calculated, based on person-years at risk. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated, using the Israeli general population as a reference.

RESULTS

Included were 1687 patients assigned to the low-risk category and 440 patients assigned to the intermediate-risk category. In the low-risk category, all-cause mortality and cancer incidence were not significantly different than expected (SMR 0·81, 95% CI 0·22-2·08 and SIR 0·76, 95% CI 0·09-2·73). In the intermediate-risk category, all-cause mortality and cancer incidence were significantly higher than expected (SMR 4·05, 95% CI 1·62-8·34 and SIR 4·52, 95% CI 1·22-11·57).

CONCLUSIONS

No increased risk of mortality or cancer incidence was found in low-risk patients treated with rhGH during childhood. Patients with prior risk factors were at higher risk of both mortality and cancer.

Growth hormone therapy for Prader-willi syndrome: challenges and solutions

Prader-Willi syndrome (PWS) is characterized by a dysregulation of growth hormone (GH)/insulin-like growth factor I axis, as the consequence of a complex hypothalamic involvement. PWS' clinical picture seems to resemble the classic non-PWS GH deficiency (GHD), including short stature, excessive body fat, decreased muscle mass, and impaired quality of life. GH therapy is able to ameliorate the phenotypic appearance of the syndrome, as well as to improve body composition, physical strength, and cognitive level. In this regard, however, some pathophysiologic and clinical questions still remain, representing a challenge to give the most appropriate care to PWS patients. Data about the prevalence of GHD in PWS children are not unequivocal, ranging from 40% to 100%. In this context, to establish whether the presence (or not) of GHD may have a different effect on clinical course during GH therapy may be helpful. In addition, the comparison of GH effects in PWS children diagnosed as small for gestational age with those obtained in subjects born appropriate for gestational age is of potential interest for future trials. Emerging information seems to demonstrate the maintenance of beneficial effects of GH therapy in PWS subjects after adolescent years. Thus, GH retesting after achievement of final height should be taken into consideration for all PWS patients. However, it is noteworthy that GH administration exerts positive effects both in PWS adults with and without GHD. Another critical issue is to clarify whether the genotype-phenotype correlations may be relevant to specific outcome measures related to GH therapy. Moreover, progress of our understanding of the role of GH replacement and concomitant therapies on bone characteristics of PWS is required. Finally, a long-term surveillance of benefits and risks of GH therapy is strongly recommended for PWS population, since most of the current studies are uncontrolled and of short duration.

GH safety workshop position paper: a critical appraisal of recombinant human GH therapy in children and adults

Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that 'for approved indications, GH is safe'; however, the statement highlighted a number of areas for on-going surveillance of long-term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement.

Burden of Growth Hormone Deficiency and Excess in Children

Longitudinal growth results from multifactorial and complex processes that take place in the context of different genetic traits and environmental influences. Thus, in view of the difficulties in comprehension of the physiological mechanisms involved in the achievement of normal height, our ability to make a definitive diagnosis of GH impairment still remains limited. There is a myriad of controversial aspects in relation to GH deficiency, mainly related to diagnostic controversies and advances in molecular biology. This might explain the diversity in therapeutic responses and may also serve as a rationale for new "nonclassical" treatment indications for GH. It is necessary to acquire more effective tools to reach an adequate evaluation, particularly while considering the long-term implications of a correct diagnosis, the cost, and safety of treatments. On the other hand, overgrowth constitutes a heterogeneous group of different pathophysiological situations including excessive somatic and visceral growth. There are overlaps in clinical and molecular features among overgrowth syndromes, which constitute the real burden for an accurate diagnosis. In conclusion, both GH deficiency and overgrowth are a great dilemma, still not completely solved. In this chapter, we review the most burdensome aspects related to short stature, GH deficiency, and excess in children, avoiding any details about well-known issues that have been extensively discussed in the literature.

The effect of a 10-week Nordic walking training program on the level of GH and LH in elderly women

OBJECTIVE

The aim of this study was to determine the effect of a 10-week Nordic walking training program on resting growth hormone (GH) and luteinizing hormone (LH) blood concentrations and their relationships to the values of inflammatory, metabolic, and muscle injury parameters in postmenopausal women with overweight and obesity.

METHODS

Thirty-two postmenopausal women with overweight or obesity (body mass index 30.5 ± 4.1 kg/m(2)), aged 59.6 ± 5.9 years were included in the investigation. Concentrations of GH, LH, C-reactive protein, total cholesterol, low density (LDL) and high density lipoprotein (HDL) cholesterol, triglycerides and albumin, as well as the plasma activity of muscle enzymes such as creatine kinase and lactate dehydrogenase, were examined before and after the participants finished a 10-week Nordic walking rehabilitation program.

RESULTS

After a 10-week rehabilitation period in accordance with a Nordic walking program, significant increases in blood concentrations of GH (median 47.5%) and HDL cholesterol (on average by 0.1%) as well as a decrease in LH values (on average by 19%), total cholesterol, LDL cholesterol and triglycerides (all on a similar average by between 0.1 and 0.2%), creatine kinase (on average by 14%), lactate dehydrogenase (on average by 4%), C-reactive protein (on average by 24%), and body mass index (on average by 5.7%) were found.

CONCLUSIONS

Nordic walking for postmenopausal women with overweight and obesity led to favorable hormonal responses, as well as improvement in muscle integrity and nutritional and inflammatory states, suggesting chronic, regular exercise as an effective tool in protecting against menopause-related catabolic processes.

Incidence of primary cancers and intracranial tumour recurrences in GH-treated and untreated adult hypopituitary patients: analyses from the Hypopituitary Control and Complications Study

OBJECTIVE

Speculation remains that GH treatment is associated with increased neoplasia risk. Studies in GH-treated childhood cancer survivors suggested higher rates of second neoplasms, while cancer risk data for GH-treated and untreated hypopituitary adults have been variable. We present primary cancer risk data from the Hypopituitary Control and Complications Study (HypoCCS) with a focus on specific cancers, and assessment of recurrence rates for pituitary adenomas (PA) and craniopharyngiomas (CP).

DESIGN

Incident neoplasms during HypoCCS were evaluated in 8418 GH-treated vs 1268 untreated patients for primary malignancies, 3668 GH-treated vs 720 untreated patients with PA history, and 956 GH-treated vs 102 untreated patients with CP history.

METHODS

Using population cancer rates, standardised incidence ratios (SIRs) were calculated for all primary cancers, breast, prostate, and colorectal cancers. Neoplasm rates in GH-treated vs untreated patients were analysed after propensity score adjustment of baseline treatment group imbalances.

RESULTS

During mean follow-up of 4.8 years, 225 primary cancers were identified in GH-treated patients, with SIR of 0.82 (95% CI 0.71-0.93). SIRs (95% CI) for GH-treated patients were 0.59 (0.36-0.90) for breast, 0.80 (0.57-1.10) for prostate, and 0.62 (0.38-0.96) for colorectal cancers. Cancer risk was not statistically different between GH-treated and untreated patients (relative risk (RR)=1.00 (95% CI 0.70-1.41), P=0.98). Adjusted RR for recurrence was 0.91 (0.68-1.22), P=0.53 for PA and 1.32 (0.53-3.31), P=0.55 for CP.

CONCLUSIONS

There was no increased risk for all-site cancers: breast, prostate or colorectal primary cancers in GH-treated patients during HypoCCS. GH treatment did not increase the risk of PA and CP recurrences.

Risk of Neoplasia in Pediatric Patients Receiving Growth Hormone Therapy--A Report From the Pediatric Endocrine Society Drug and Therapeutics Committee

CONTEXT

GH and IGF-1 have been shown to affect tumor growth in vitro and in some animal models. This report summarizes the available evidence on whether GH therapy in childhood is associated with an increased risk of neoplasia during treatment or after treatment is completed.

EVIDENCE ACQUISITION

A PubMed search conducted through February 2014 retrieved original articles written in English addressing GH therapy and neoplasia risk. Subsequent searches were done to include additional relevant publications.

EVIDENCE SYNTHESIS

In children without prior cancer or known risk factors for developing cancer, the clinical evidence does not affirm an association between GH therapy during childhood and neoplasia. GH therapy has not been reported to increase the risk for neoplasia in this population, although most of these data are derived from postmarketing surveillance studies lacking rigorous controls. In patients who are at higher risk for developing cancer, current evidence is insufficient to conclude whether or not GH further increases cancer risk. GH treatment of pediatric cancer survivors does not appear to increase the risk of recurrence but may increase their risk for subsequent primary neoplasms.

CONCLUSIONS

In children without known risk factors for malignancy, GH therapy can be safely administered without concerns about an increased risk for neoplasia. GH use in children with medical diagnoses predisposing them to the development of malignancies should be critically analyzed on an individual basis, and if chosen, appropriate surveillance for malignancies should be undertaken. GH can be used to treat GH-deficient childhood cancer survivors who are in remission with the understanding that GH therapy may increase their risk for second neoplasms.

Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis

Background. Growth hormone (GH) and insulin-like growth factor (IGF-1) are fundamental in skeletal growth during puberty and bone health throughout life. GH increases tissue formation by acting directly and indirectly on target cells; IGF-1 is a critical mediator of bone growth. Clinical studies reporting the use of GH and IGF-1 in osteoporosis and fracture healing are outlined. Methods. A Pubmed search revealed 39 clinical studies reporting the effects of GH and IGF-1 administration on bone metabolism in osteopenic and osteoporotic human subjects and on bone healing in operated patients with normal GH secretion. Eighteen clinical studies considered the effect with GH treatment, fourteen studies reported the clinical effects with IGF-1 administration, and seven related to the GH/IGF-1 effect on bone healing. Results. Both GH and IGF-1 administration significantly increased bone resorption and bone formation in the most studies. GH/IGF-1 administration in patients with hip or tibial fractures resulted in increased bone healing, rapid clinical improvements. Some conflicting results were evidenced. Conclusions. GH and IGF-1 therapy has a significant anabolic effect. GH administration for the treatment of osteoporosis and bone fractures may greatly improve clinical outcome. GH interacts with sex steroids in the anabolic process. GH resistance process is considered.