Although survivors of childhood acute lymphoblastic leukemia have an increased risk of conditions such as obesity and cardiovascular disease, many appear to avoid simple exercise and healthy lifestyle changes that could decrease those risks, according to an article in the July issue of Cancer Epidemiology, Biomarkers, & Prevention.

The team of researchers based at Memorial Sloan-Kettering Cancer Center found that the adults were less physically active than the general U.S. population. Furthermore, adult survivors who received cranial radiotherapy as children reported the lowest activity among all adults, suggesting that the type of therapy administered to a child may impair his or her physical activity in the future.

To protect adult childhood cancer survivors from a future of disease, researchers say families should work with health care providers to develop plans for healthier and more active lifestyles.

“Research shows that physical activity can undo risk caused by treatment,” said senior author Kevin C. Oeffinger, MD, from Memorial Sloan-Kettering Cancer Center, New York, N.Y. “Small, incremental steps can make a big difference in improving health outcomes.”

Oeffinger and colleagues compared the physical activity levels of over 2,600 adult survivors ages 18 to 44 years as reported by patients in the Childhood Cancer Survivor Study (CCSS) in 2003, to physical activity of age-matched adults in the general U.S. population, as reported in the 2003 Behavioral Risk Factor Surveillance System (BRFSS) survey. The CCSS is a multi-institution study sponsored by the National Cancer Institutes, and the BRFSS is a state-based survey conducted by the Centers for Disease Control (CDC). In both surveys, study participants were asked to report the number of times they had participated in physical activity or exercise during the prior month.

The study found that adult survivors were less likely to meet the CDC physical activity guidelines (52.8 percent vs. 48.2 percent) and more likely to report no moderate or vigorous physical activity during the month preceding the survey (23 percent vs. 20.3 percent), with the highest levels of physical inactivity in survivors who had received cranial radiotherapy. Women who were treated with a moderate dose of cranial radiotherapy were twice as likely to be physically inactive as women in the general population.

“It’s important to remember that these patients are not couch potatoes or lazy,” said Dr. Oeffinger. “Our findings suggest that cranial radiotherapy has fundamentally altered something in the central nervous system that’s leading to a decrease in levels of physical activity.”

Because exercise reduces the risk of developing cardiovascular diseases, the CDC advises Americans to engage in a minimum of 30 minutes of moderate physical activities such as brisk walking, gardening, or vacuuming five days per week, or vigorous physical activities such as running, aerobics, or heavy yard work three days per week. While more than half of the U.S. population fails to meet CDC recommendations, low physical activity among adult survivors may further increase this group’s already high risk for obesity, cardiovascular disease and mortality, researchers said.

Though the addition of cranial radiotherapy over 40 years ago led to a marked increase in survival rates, research has since linked it to reduced cognitive function, hormonal imbalance and obesity. In some patients, cranial radiotherapy may cause loss of postural and motor control, balance, and/or muscle weakness, which may lead to decreased physical activity.

Because of the risks associated with it and the availability of improved chemotherapy drugs, cranial radiotherapy is now only used to treat children with particularly aggressive forms of the disease. According to Oeffinger, approximately 10 to 15 percent of patients today are treated with cranial radiotherapy.

“The storyline is that physical inactivity and obesity outcomes are based upon type of therapy administered to patient,” said Oeffinger. “Importantly, there are things we can do to intervene and to help childhood cancer survivors to regain active lifestyles that will protect the patient in the long run.”