How Cancer Affects Childhood Growth

Childhood cancer patients and survivors are at increased risk for growth disturbances, for myriad reasons, and it is important to periodically monitor their growth, according to a paper recently published in The Journal of Clinical Endocrinology & Metabolism.

Tomoko Yoshida, MD, PhD, and Angela Delaney, MD, both of St. Jude Children’s Research Hospital in Memphis, Tenn., point out that the chance of curing cancer in children and adolescents is dramatically increasing, as treatments and supportive care continue to improve. But with this increase comes awareness of complications among survivors. “Growth impairment is one of the major complications related to cancer and its treatment,” Yoshida and Delaney write. “In fact, the prevalence of short adult height, defined as a height more than 2 SD score (SDS) below the mean for age and sex is reported to be roughly 9 percent among the overall survivor population.”

The authors go on to write that because growth is an important measure of health clinicians should monitor the growth rate in these children and adolescents. Yoshida and Delaney lay out how cancer and its treatment impact growth in children, from hormonal and nonhormonal standpoints. They cover many factors that can disturb growth, from simple nutrition to physiological stress to treatments like radiation and chemotherapy.

Endocrine causes of short stature and impaired growth include growth hormone deficiency (GHD). For example, cranial radiation therapy (CRT) is a primary risk factor for GHD among cancer survivors. Young age at cancer diagnosis is also a general risk factor for GHD, according to the authors.

Then there’s treatment with growth hormone therapy (GHT), but the authors note that some studies have shown that cancer survivors with GHD don’t get the height benefit from GHT as they should. The risk factors for impaired growth even with GHT are younger age at radiation and shorter stature at the start of GHT. Improved adult height is also observed among survivors with GHT following exposure to [craniospinal radiation (CSI)] or [ total body irradiation (TBI)] who demonstrate growth retardation attributable to both GHD and spine growth restriction,” the authors write, adding that “ there is a potential increased risk of disproportionate growth in this population because growth retardation due to spinal radiation is not responsive to GHT.”

The review covers a lot, including hypothyroidism and overgrowth caused by some types of brain tumors. “[Cancer] patients often receive multimodal treatments (eg, radiation plus chemotherapy), and survivors may experience coexistence of multiple conditions that can affect their growth,” Yoshida and Delaney conclude. “The mechanism, severity, and latency interval of growth disturbance varies among individuals. Therefore, it is important to periodically monitor their growth based on individual risk factors.”