麻豆传媒

Survivors of childhood cancer face challenges from bone mineral density (BMD) deficits due to treatment exposures and other factors, some of which may be modifiable, a cohort study suggested.

Among over 3,900 patients who had survived at least 5 years after cancer diagnosis, treatment exposures (including age at diagnosis), comorbid conditions, and smoking and sedentary behavior explained 18.5%, 10.2%, and 7% of moderate deficits and 55.4%, 51.1%, and 9.9% of severe deficits, reported Kirsten K. Ness, PT, PhD, of St. Jude Children's Research Hospital in Memphis, Tennessee, and colleagues in .

Factors associated with severe deficits included:

• Cranial radiotherapy (30 Gy or greater; OR 5.22, 95% CI 3.74-7.30; attributable fraction 33%)
• Testicular or pelvic radiation (OR 1.70, 95% CI 1.19-2.44; attributable fraction 11.5%)
• Hypogonadism (OR 3.27, 95% CI 2.35-4.55; attributable fraction 25.1%)
• Growth hormone deficiency (GHD; OR 5.28, 95% CI 3.68-7.56; attributable fraction 26%)
• Smoking (OR 1.71, 95% CI 1.21-2.43; attributable fraction 6.7%)
• Sedentary behavior (OR 2.06, 95% CI 1.15-3.69; attributable fraction 6.2%)

Survivors with BMD deficits were less likely to live alone and to be employed, more likely to require personal care assistance, and more likely to have depressive symptoms and a poor quality of life.

"Historically, low bone density has been challenging to address among childhood cancer survivors," wrote Emily M. Stein, MD, MS, of the Hospital for Special Surgery in New York City, and Emily S. Tonorezos, MD, MPH, of the National Cancer Institute, in a , noting that most bone-modifying agents aren't appropriate for pediatric patients.

However, the results from this study "indicate that low BMD is common and, in many circumstances, addressable," they observed, pointing out that about a quarter of study participants with moderate BMD deficits at the time of initial evaluation improved over the follow-up period, "suggesting that some skeletal deficits may be reversible."

For example, they said that smoking cessation and weight-bearing physical activity "should be prioritized in this population." In addition, conditions associated with low BMD, such as GHD or hypogonadism, "are also treatable."

Ness and colleagues concluded that "future research should examine modifiable risk factors (hypogonadism, GHD, smoking, and sedentary behavior) for possible targeted interventions."

"Survivors should be screened for BMD deficits during follow-up and counselled to optimize health behaviors to minimize progression of bone loss," they wrote. "Appropriate counselling is particularly important for survivors as they enter adulthood, moving from pediatric to adult healthcare systems when primary care clinicians are largely responsible for managing their healthcare."

This study used cross-sectional and longitudinal data from the St Jude Lifetime (SJLIFE) cohort, a retrospectively constructed cohort with prospective follow-up. All participants were adult survivors of childhood cancer who were diagnosed between 1962 and 2012 and survived 5 years or more from diagnosis. Median age was 31.7, 52.6% were men, 80.4% were white, and 15.5% were Black.

Of 1,607 survivors who had multiple BMD evaluations (median survival 22.5 years), 20.9% had moderate and 5.9% had severe BMD deficits at baseline. Of the 1,200 survivors with normal BMD at baseline, 8% developed moderate or severe BMD deficits. Of the 316 survivors with a moderate BMD deficit at baseline, 65% continued to have a moderate deficit, 11% declined to a severe deficit, and 23% were able to improve to normal BMD status.

Ness and colleagues acknowledged that their study had several limitations, including the fact that it consisted mainly of non-Hispanic white and Black participants. In addition, they pointed out that their clinical assessment did not include trauma history or spine radiographs for every participant, which meant they were unable to evaluate prevalent scoliosis, prolonged periods of immobilization, or traumatic fractures as risk factors for low BMD.

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