medwireNews: There is no evidence that growth hormone (GH) therapy increases the likelihood of neoplasms in children with no additional risk factors, says the Pediatric Endocrine Society Drug and Therapeutics Committee.

This is despite “plausible molecular mechanisms and epidemiological evidence associating increased IGF-I [insulin-like growth factor-1] levels with the development of cancer”, says the team led by Sripriya Raman (University of Missouri, Kansas City, USA).

In their systematic review, Raman and colleagues identified a total of 10 clinical studies addressing cancer risk in people treated with GH as children. Six of these were large post-marketing or cohort studies, and none produced evidence of increased cancer risk at the time of treatment. There was also no consistent evidence of increased risk in adults who had received GH therapy during childhood.

However, there were no data addressing neoplasm risk in GH-treated children with other factors predisposing them to malignancy.

“In the absence of such evidence, clinicians should consider whether raising IGF-I levels might constitute an additional risk for neoplasia in patients predisposed to tumor development”, advises the team in The Journal of Clinical Endocrinology & Metabolism.

If children with increased predisposition to cancer undergo GH therapy, they should be regularly screened for cancers and their IGF-1 levels maintained within an age-appropriate range, suggest Raman et al.

The research, including the US Childhood Cancer Survivor Study, also suggests GH therapy does not increase the risk of cancer recurrence. However, it did find that treatment may double the risk of new neoplasms in paediatric cancer survivors, who already have a significantly increased risk of new cancers. But other studies did not find an increased risk of new primary tumours in GH-treated cancer survivors.

The team therefore says that paediatric cancer survivors without signs of active cancer may undergo GH treatment “without concern” of provoking recurrence, but advises: “Patients and caregivers should be informed that there may be an increase in the risk overall for subsequent primary neoplasms.”

By Eleanor McDermid, Senior medwireNews Reporter

J Clin Endocrinol Metab 2015; Advance online publication

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