This podcast describes a study examining aerobic capacity in a cohort of over 1200 adult survivors of childhood cancer and related impairments of cardiac, pulmonary and neuromuscular body systems, to understand how aerobic capacity influences all-cause mortality.
This JCO Podcast provides observations and commentary on the JCO article 'Exercise Intolerance, Mortality, and Organ System Impairment in Adult Survivors of Childhood Cancer' by Ness et al. My name is Kristin Campbell, and I am a licenced physical therapist and associate professor in the Faculty of Medicine at the University of British Columbia in Vancouver, Canada. My oncologic specialty is in rehabilitation, primarily related to breast cancer.
Exercise intolerance is a global measure of functional capacity that reflects the complex integration of body systems. It is well established in the general population that exercise intolerance is predictive of future cardiovascular health and mortality. Whether this relationship also existed for adult survivors of childhood cancer was examined by Ness and colleagues in the article that accompanies this podcast. . In the largest study to date of its kind, this manuscript reports on a comprehensive and methodologically rigorous examination of exercise intolerance measured by a gold standard maximal cardiopulmonary exercise test in over 1200 adult survivors of childhood cancer who are part of the St. Jude’s Lifetime Cohort Study.
The first main finding is the low levels of exercise capacity in this sample of childhood cancer survivors despite a relatively young mean age of 35 years. The observed maximal aerobic capacity, or VO2peak, ranged on average between 25-27 ml/kg/min, which fall into the “poor” or “very poor” categories of age and sex matched normative values. Compared to 285 community controls who were friends or family members of the cohort patients, the observed maximal aerobic capacity values for childhood cancer survivors were on average 22% lower. In fact, these values are actually more consistent with values seen in healthy adults in their seventies or eighties. Furthermore, the low value of maximal aerobic capacity may also be an underestimate. Thirteen percent of individuals in the St. Jude’s cohort who agreed to participate in the study were not cleared to undertake the maximal cardiopulmonary exercise test due to recent diagnosis of cardiac or pulmonary disease, or lab values and symptoms indicating cardiac or pulmonary issues. This suggests that the prevalence of exercise intolerance may be even greater in a real-world clinical setting than that observed in this cohort.
To examine the association between exercise intolerance and mortality, the authors defined exercise intolerance as a maximal aerobic capacity of A unique feature of this study is that the authors also undertook comprehensive measures of host, treatment, and lifestyle factors to better understand how these factors influence exercise intolerance. These additional measures included cardiac imaging at rest, autonomic response, measured by blood pressure response to the maximal graded exercise test, standard pulmonary function testing, quadriceps strength testing, and peripheral sensorimotor function using the modified total neuropathy scale. This data provides a rare look into the acute and chronic responses to exercise of the cardiovascular, pulmonary, autonomic and neuromuscular systems in those exposed or not exposed to cardiotoxic agents and will appeal to those an interest in exercise physiology. Odds of exercise intolerance were highest with reporting Of note, the type of treatment received impacted the presentation of exercise intolerance. Lower exercise tolerance was observed in individuals who received >350 mg/m2 of anthracyclines, >30 Gy of chest radiation, >20 Gy of cranial radiation and receipt of carboplati