Scott JM, et al. - Researchers explored the relationship between vigorous exercise and change in exercise with mortality in adult survivors of childhood cancer in a cohort analysis using a questionnaire after a median follow-up of 10 years. They found a lower risk of mortality in adult survivors of childhood cancer in relation to vigorous exercise in early adulthood and increased exercise over 8 years.

Methods

• In this multicenter cohort analysis, researchers included 15,450 adult cancer survivors from pediatric tertiary hospitals in the US and Canada diagnosed before age 21 years between 1970 and 1999 enrolled in the Childhood Cancer Survivor Study, with follow-up through December 31, 2013.
• Self-reported vigorous exercise in metabolic equivalent task (MET) hours per week was included as exposure.
• They used multivariable piecewise exponential regression analysis to evaluate the link between vigorous exercise and change in vigorous exercise and cause-specific mortality.
• All-cause mortality was the primary outcome.
• Cause-specific mortality (recurrence/progression of primary malignant neoplasm and health-related mortality) was secondary end points.
• Using the National Death Index, the outcomes were assessed.

Results

• Data showed that 15,450 survivors had a median age at interview of 25.9 years (interquartile range [IQR], 9.5 years) and were 52.8% male.
• Researchers reported 1,063 deaths (811 health-related, 120 recurrence/progression of primary cancer, 132 external/unknown causes) during a median follow-up of 9.6 years (IQR, 15.5 years).
• At 15 years, the observed cumulative incidence of all-cause mortality was as follows: 11.7% (95% CI, 10.6%-12.8%) for those who exercised 0 MET-hours/week, 8.6% (95% CI, 7.4%-9.7%) for 3 to 6 MET-hours/week, 7.4% (95% CI, 6.2%-8.6%) for 9 to 12 MET-hours/week, and 8.0% (95% CI, 6.5%-9.5%) for 15 to 21 MET-hours/week (P < .001).
• They also noted that, after adjusting for chronic health conditions and treatment exposures (P=.02 for trend), a significant inverse association across quartiles of exercise and all-cause mortality was present.
• Among a subset of 5,689 survivors, increased exercise (mean [SD], 7.9 [4.4] MET-hours/week) over an 8-year period was related to a 40% attenuation in all-cause mortality rate vs maintenance of low exercise (rate ratio,0.60; 95% CI, 0.44-0.82; P=.001).