Survivors of childhood cancer are very likely to develop hormonal abnormalities as they age, underscoring the need for lifelong medical monitoring, according to a new study led by Children's Hospital of Philadelphia.
The context for that finding is heartening: Pediatric cancer treatments have improved so much that more than 80 percent of children live at least five years. The United States has an estimated 420,000 childhood cancer survivors.
But chemotherapy and radiation take a toxic toll on young bodies. And their endocrine systems -- the glands that produce hormones that regulate metabolism, growth, reproduction, and more -- are particularly vulnerable.
To assess the development of endocrine abnormalities, the researchers analyzed the self-reported conditions of 14,000 survivors who were followed by the Childhood Cancer Survivor Study, a federally funded study begun in 1994. The survivors' median age at diagnosis was 6 (meaning half were younger, half were older), and their median age at their last follow-up was 32.
Thyroid disorders, including underactive or overactive thyroid and thyroid cancer, became increasingly common as the survivors aged, particularly for those treated with radiation. For example, nearly 40 percent of 1,800 survivors whose thyroid glands were exposed to radiation in childhood developed underactive thyroids by age 35.
Survivors also had high rates of diabetes, obesity, osteoporosis, fertility problems, and growth hormone deficiency, the researchers found.
They noted that endocrine conditions "with vague or minimal symptoms...frequently remain undiagnosed or undertreated because of a lack of formal assessment."
The study, published Tuesday in the Journal of Clinical Oncology, bolsters "the importance of lifelong screening of childhood cancer survivors for endocrine abnormalities," wrote the researchers, led by Sogol Mostoufi-Moab, an oncologist and endocrinologist at Children's Hospital.