Childhood cancer survivors who get plenty of vigorous exercise may live longer than their counterparts who aren’t very active, a recent study suggests.
“In cancer survivors, cancer treatment causes what we consider to be an accelerated aging process,” that can lead to premature deaths, said senior study author Lee Jones, chief of the exercise oncology service at Memorial Sloan Kettering Cancer Center in New York City.
So, findings showing that exercise may attenuate or slow this process are not only novel, but critically important for patients since exercise is an intervention they can do right now,” Jones said by email.
Researchers examined survey data on the frequency, intensity and duration of physical activity for 15,450 adults who had been treated for childhood cancer in the U.S. and Canada between 1970 and 1999. By the time half the participants had been followed for 9.6 years, 1,063 of the whole group had died.
At the start of the study, half of the childhood cancer survivors were at least 26 years old.
Researchers asked study participants how often they exercised, and how intensely, as well as what activities they did. Then, the study team scored participants’ exercise levels and intensity based on a measure known as metabolic equivalent of task (MET) hours per week.
After 15 years, the overall mortality rate from all causes was almost 12 percent for people who didn’t exercise.
People who achieved 3 to 6 MET hours per week had a mortality rate of 8.6 percent at 15 years, while participants who managed 9 to 12 MET hours a week had a mortality rate of 7.4 percent. The mortality rate was 8 percent for people who achieved 15 to 21 MET hours per week.
Increasing exercise levels over time appeared to boost survival odds, researchers report in JAMA Oncology.
Among a subset of 5,689 survivors, inactive people who increased exercise by an average of about 8 MET hours per week over an eight-year period were 40 percent less likely to die during the study period than participants who remained consistently inactive.
It’s possible exercise benefits cancer survivors in much the same way that it helps other people - by promoting a healthy heart, Jones said.
“The primary risk of dying prematurely in childhood cancer survivors is cardiovascular disease,” Jones noted. “Exercise may attenuate either the development or progression of cardiovascular disease in all the ways it does so in the general population.”
Among other things, regular vigorous exercise can help bolster the immune system and make it easier for people control their blood pressure, cholesterol and blood sugar.
However, the study wasn’t a controlled experiment designed to prove whether or how exercise might directly boost longevity for childhood cancer survivors.
Another limitation of the study is its reliance on survey participants to accurately report the frequency and intensity of any exercise. In addition, it excluded some of the sickest childhood cancer survivors who died before the start of the study or before they could complete follow-up questionnaires on their exercise habits.
“These data confirm and extend to cancer survivors our longstanding medical and research experience which have shown that people who exercise generally live longer and better lives,” said Dr. Venkatesh Murthy, a researcher at the University of Michigan in Ann Arbor who wasn’t involved in the study.
“What is less clear from the study is what amount of exercise is necessary or how to best implement programs to encourage exercise during and after treatment for cancer,” Murthy said by email.
Still, it makes sense for cancer survivors to get as much exercise as they can manage.
“Exercise has positive effects on many parts of the body including muscles, bones, blood vessels, and heart and lung function,” Murthy said. “It can also improve mood and promote general well-being.”