Individuals who had cancer as a child may be at increased risk of being obese due to the therapies they received during their youth.

The finding comes from a new study published early online in Cancer, a peer-reviewed journal of the American Cancer Society.

The study’s results suggest the need for effective counselling and weight loss interventions for certain childhood cancer survivors.

Previous research has shown that obesity rates are elevated in childhood cancer survivors who were exposed to cranial radiation, which is used to prevent or delay the spread of cancer to the brain.

A team led by Carmen Wilson, PhD and Kirsten Ness, PhD, of St. Jude Children’s Research Hospital in Memphis, designed a study to estimate the prevalence of obesity among childhood cancer survivors and to identify the clinical and treatment-related risks for obesity in these individuals.

The study also looked for potential genetic factors that might play a role.

The study included 1,996 survivors previously treated for cancer at St. Jude who had been diagnosed with cancer at least 10 years ago.

The researchers found that 47 percent of survivors who had received cranial radiation were obese, compared with 29.4 percent of survivors who had not received cranial radiation.

The likelihood of obesity increased among survivors treated with cranial radiation who had also received glucocorticoids, or who were younger at the time of diagnosis.

Also, certain variants in genes involved with neurons’ growth, repair, and connectivity were linked with obesity among survivors treated with cranial radiation.

Survivors who had been treated with chest, abdominal, or pelvic radiation were half as likely to be obese as those who did not receive these treatments.

Dr. Wilson noted that the findings may help identify cancer survivors who are most likely to become obese, and could provide a foundation for future research efforts aimed at characterising molecular pathways involved in the link between childhood cancer treatment and obesity.

“Also, the ability to identify patients at increased risk may guide selection of therapeutic protocols that will maximiser treatment outcomes while simultaneously minimising the risk of long-term complications among children diagnosed with cancer,” said Dr. Ness.

Reference: Carmen L. Wilson et al (2015). Genetic and clinical factors associated with obesity among adult survivors of childhood cancer: a report from the St. Jude Lifetime cohort. Cancer

Source: Wiley