The analyses also demonstrated that survivors of abdominal and pelvic solid tumors had lower relative lean body mass than the general population and that the lower relative lean body mass was associated with the dose of prior abdominal or pelvic radiation. Lean body mass, which measures the non-fat content of the body, is related to basal metabolic rate; therefore, an individual with lower lean body mass burns fewer calories while resting than someone with higher lean body mass, Wilson explained.

There was no significant difference in relative fat body mass between survivors and the general population; however, survivors who had high relative fat mass had reduced quadricep strength and poor physical performance (as measured by a sit-and-reach test and distance covered during a six-minute walk) compared with survivors who had low relative fat mass.


Author's Comments: "It is possible that abdominal and pelvic-directed radiation therapy damages postural muscles or subtly impairs sex hormone production, ultimately affecting muscle mass," said Wilson. She explained that radiation therapy has been shown to cause muscle injury, resulting in muscle fiber loss and loss of muscle regenerative cells, in animal studies. Wilson added that lifestyle choices may also impact relative lean mass and cardiometabolic health among survivors.

Wilson suggested that future research could examine the impact of radiation therapy and other cancer treatments on fat distribution across the body since increased abdominal obesity has been shown to be a better predictor of adverse health effects than measures of overall obesity.

In addition, Wilson is interested in exploring how interventions directed at lifestyle behaviors could improve lean mass and decrease fat mass among survivors of pediatric cancers. "While it may not be possible to avoid radiation therapy as a key treatment for many solid tumors, early research suggests that resistance training interventions in survivors increase lean mass," said Wilson. "Further work is needed to see if training would also impact cardiometabolic impairments in this population."

Study Limitations: A limitation of the study is that cardiometabolic outcomes may have been measured differently in the study cohort compared with those surveyed by NHANES.

Funding & Disclosures: The study was supported by a Cancer Center Support Grant and the American Lebanese Syrian Associated Charities. Wilson declares no conflicts of interest.

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