Physical Activity at Early Stages of Treatment May Be Key
WASHINGTON, DC — Children undergoing chemotherapy for the most common form of childhood cancer often experience harmful weight gain that can continue for years after their treatment, increasing their risk of obesity and its many related chronic health issues – including adult cancers, heart disease and type 2 diabetes. This is the conclusion of new research presented today at the American Institute for Cancer Research (AICR) Annual Research Conference.
Presented at a session focused on improving the health of childhood cancer survivors, one study points to a crucial window of time early in the child’s cancer treatment when physical activity, and other healthy lifestyle habits could have the greatest impact on preventing the long-term weight gain associated with childhood cancer survivors.
Crucial Window of Time
Involving 83 children being treated for acute lymphoblastic leukemia (ALL), the most common childhood cancer, between 1985 and 2010, the new study, published earlier this year in Pediatric Blood and Cancer by pediatric oncologist Susan K. Parsons, MD, MRP, and her colleagues at Tufts University found that during the earliest phase of treatment, called induction, children start to gain weight. Possible reasons for this weight gain include the use of corticosteroids and possible leptin resistance, which affect appetite, as well as muscle weakness and physical challenges associated with certain cancer treatments that make being active more difficult.
What surprised the research team, however, was that the weight levels of the children in the study remained elevated years after the treatment. The researchers examined the body mass index (BMI) of the children at several key time points – diagnosis; early phase of treatment (after induction); later phase of treatment (after consolidation); every 6 months during maintenance; and yearly for up to 5 years after treatment concluded. It was during the induction when weight increased. BMI then dropped slightly, but then increased again during the first six months of maintenance, where it remained elevated.
“I would have predicted going into the study that children would have had some increase in weight due to treatment with corticosteroids,” said Parsons. “I didn’t expect that their weight would go up and stay elevated after the kids were back at school and doing more normal activities. That was really fascinating.”
“This study is really important because it shows that weight gain persisted through treatment and into survivorship,” said Parsons. “Patients who gained that big spike in weight during treatment were more likely to remain overweight or obese after treatment.”
Adding to these findings, a pilot study of approximately 20 children diagnosed with cancer points to a lack of physical activity, not diet, as playing a key role. The study was published in the Journal of Pediatric Hematology/Oncology. Using a special laboratory technique to assess the metabolic activity of these children, the study showed the children were expending relatively little energy, putting them at increased risk for obesity and obesity-related chronic diseases.
“We were surprised at the low levels of total energy expenditure, which were nearly 500 calories a day lower than what kids are expending who are getting the recommended levels of physical activity. It’s low enough that we would consider them to be a sedentary population,” said Parsons. “What we don’t know from these data is whether that is something related to the illness or recovery: is it related to the treatment, learned habits as a result of going through the treatment, or is it that they never resume normal levels of activity?”
Our data suggests that healthcare providers should support parents in encouraging children to maintain healthy eating and physical activity right from the start,” said Parsons.
Exercise Effective Against Survivors’ Increased Heart Disease Risk
Examining the effect of physical activity once childhood cancer survivors reach adulthood, data presented by Kirsten Ness, PT, PhD, of St. Jude Children’s Research Hospital, at the AICR Annual Research Conference demonstrates that being active can significantly reduce the risk of cardiovascular disease and frailty, which are typically seen in adults over age 65 but can appear in young adult cancer survivors as the “late effects” of their cancer treatment.
A study published this month in the Journal of Clinical Oncology by Lee Jones, PhD, and colleagues reported that adult survivors of childhood Hodgkin lymphoma who were vigorous exercisers had a 51% reduction in the risk of cardiovascular problems later in life compared with survivors who did not meet the recommended amount of vigorous exercise. Previous research by Ness and her colleagues shows that young adult survivors of a childhood cancer have the rates of frailty as people aged 65 years to 101 years, largely the result of the loss of lean muscle mass where physical activity can play a preventive role.
Ness was also part of another study published this year in Cancer, which revealed that approximately three quarters of young adult survivors of childhood cancer have more than double the risk of developing metabolic syndrome after diagnosis. Metabolic syndrome includes a group of risk factors that raise the risk for heart disease and other health problems. Childhood cancer survivors who met the fewest AICR Recommendations for healthy eating and lifestyle were more than twice as likely to develop metabolic syndrome as survivors who practiced at least four of the healthy habits.
“Childhood cancer survivors at one time were told not to do anything, to just rest.” said Ness. But it’s now clear that healthcare providers need to let them know about the benefits of physical activity, and help these survivors understand how to incorporate exercise into their life.
“A large proportion of childhood cancer survivors are at risk for poor metabolic health and a host of health risks, such as pulmonary disease, some cardiac disease, earlier mortality and obesity,” Ness said. “What we’re seeing that’s interesting is how much the influence of lifestyle and physical activity is important.”
- Parsons study published in Pediatric Blood and Cancer July 2014 (epub in Jan14)
- Ness study published in Journal of Clinical Oncology October 14, 2014
- Ness study published in Cancer Sep 2014
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