Exercise Intolerance, Mortality, and Organ System Impairment in Adult Survivors of Childhood Cancer

The Future of Childhood Cancer Survivorship: Challenges and Opportunities for Continued Progress

As treatment evolves and the population who survive childhood cancer ages and increases in number, researchers must use novel approaches to prevent, identify and mitigate adverse effects of treatment. Future priorities include collaborative efforts to pool large cohort data to improve detection of late effects, identify late effects of novel therapies, and determine the contribution of genetic factors along with physiologic and accelerated aging among survivors. This knowledge should translate to individual risk prediction and prevention strategies. Finally, we must utilize health services research and implementation science to improve adoption of survivorship care recommendations outside of specialized pediatric oncology centers.

Cardiac biomarkers and association with subsequent cardiomyopathy and mortality among adult survivors of childhood cancer: A report from the St. Jude Lifetime Cohort

BACKGROUND

Survivors of childhood cancer exposed to cardiotoxic therapies are at significant cardiovascular risk. The utility of cardiac biomarkers for identifying the risk of future cardiomyopathy and mortality is unknown.

METHODS

N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) were assessed in 1213 adults 10 or more years from a childhood cancer diagnosis; 786 were exposed to anthracycline chemotherapy and/or chest-directed radiation therapy (RT). NT-proBNP values above age- and sex-specific 97.5th percentiles were considered abnormal. Generalized linear models estimated cross-sectional associations between abnormal NT-proBNP and anthracycline or chest RT doses as risk ratios with 95% confidence intervals (CIs). A Poisson distribution estimated rates and a Cox proportional hazards model estimated hazard ratios (HRs) for future cardiac events and death.

RESULTS

At a median age of 35.5 years (interquartile range, 29.8-42.5 years), NT-proBNP and cTnT were abnormal in 22.5% and 0.4%, respectively. Exposure to chest RT and exposure to anthracycline chemotherapy were each associated with a dose-dependent increased risk for abnormal NT-proBNP (P for trend <.0001). Among exposed survivors with no history of Common Terminology Criteria for Adverse Events-graded cardiomyopathy and with normal systolic function, survivors with abnormal NT-proBNP had higher rates per 1000 person-years of cardiac mortality (2.93 vs 0.96; P < .0001) and future cardiomyopathy (32.10 vs 15.98; P < .0001) and an increased risk of future cardiomyopathy (HR, 2.28; 95% CI, 1.28-4.08) according to a multivariable assessment.

CONCLUSIONS

Abnormal NT-proBNP values were prevalent and, among survivors who were exposed to cardiotoxic therapy but did not have a history of cardiomyopathy or current systolic dysfunction, identified those at increased risk for future cardiomyopathy. Further longitudinal studies are needed to confirm this novel finding.

Cardiovascular Family History Increases Risk for Late-Onset Adverse Cardiovascular Outcomes in Childhood Cancer Survivors: A St. Jude Lifetime Cohort Report

BACKGROUND

Survivors of childhood cancer have an increased risk of therapy-related cardiovascular disease. It is not known whether family history of cardiovascular disease further increases risk of adverse cardiovascular outcomes among survivors.

METHODS

Family history of cardiovascular disease was collected from 1,260 survivors [median age at diagnosis, 8 years (range, 0-23); age at last follow-up, 35 years (range, 18-66)] of childhood cancer in the St. Jude Lifetime Cohort Study. Multivariable risk models evaluated associations with cardiovascular disease (Common Terminology Criteria for Adverse Events grade 2-4 events) and cardiovascular risk factors.

RESULTS

Among survivors exposed to chest-directed radiation and/or anthracycline chemotherapy (n = 824), 7% reported a first-degree family history of heart failure, 19% myocardial infarction, 11% stroke, 26% atherosclerotic disease (myocardial infarction and/or stroke), 62% hypertension, and 31% diabetes mellitus. Eighteen percent of exposed survivors developed heart failure, 9% myocardial infarction, 3% stroke, 11% atherosclerotic disease, 30% hypertension, and 9% diabetes mellitus. Having a first-degree family history of atherosclerotic disease was independently associated with development of treatment-related heart failure [RR, 1.38; 95% confidence interval (CI), 1.01-1.88; P = 0.04] among exposed survivors. Risk for hypertension was increased among exposed survivors with a first-degree family history of hypertension (RR, 1.55; 95% CI, 1.26-1.92; P < 0.0001) or of any cardiovascular disease [myocardial infarction, stroke, or heart failure (RR, 1.30; 95% CI, 1.06-1.59; P = 0.01)].

CONCLUSIONS

Family history of cardiovascular disease and cardiovascular risk factors independently increased risk of heart failure and hypertension among survivors of childhood cancer exposed to cardiotoxic therapies.

IMPACT

These data show the importance of cardiovascular family history as a risk factor for cardiovascular disease in survivors of childhood cancer.

Exercise cardiovascular magnetic resonance reveals reduced cardiac reserve in pediatric cancer survivors with impaired cardiopulmonary fitness

BACKGROUND

Pediatric cancer survivors are at increased risk of cardiac dysfunction and heart failure. Reduced peak oxygen consumption (peak VO2) is associated with impaired cardiac reserve (defined as the increase in cardiac function from rest to peak exercise) and heart failure risk, but it is unclear whether this relationship exists in pediatric cancer survivors. This study sought to investigate the presence of reduced peak VO2 in pediatric cancer survivors with increased risk of heart failure, and to assess its relationship with resting cardiac function and cardiac haemodynamics and systolic function during exercise.

METHODS

Twenty pediatric cancer survivors (8-24 years; 10 male) treated with anthracycline chemotherapy ± radiation underwent cardiopulmonary exercise testing to quantify peak VO2, with a value < 85% of predicted defined as impaired peak VO2. Resting cardiac function was assessed using 2- and 3-dimensional echocardiography, with cardiac reserve quantified from resting and peak exercise heart rate, stroke volume index (SVI) and cardiac index (CI) using exercise cardiovascular magnetic resonance (CMR).

RESULTS

Twelve of 20 survivors (60%) had reduced peak VO2 (70 ± 16% vs. 97 ± 14% of age and gender predicted). There were no differences in echocardiographic or CMR measurements of resting cardiac function between survivors with normal or impaired peak VO2. However, those with reduced peak VO2 had diminished cardiac reserve, with a lesser increase in CI and SVI during exercise (Interaction P < 0.01 for both), whilst the heart rate response was similar (P = 0.71).

CONCLUSIONS

Whilst exercise intolerance is common among pediatric cancer survivors, it is poorly explained by resting measures of cardiac function. In contrast, impaired exercise capacity is associated with impaired haemodynamics and systolic functional reserve measured during exercise. Consequently, measures of cardiopulmonary fitness and cardiac reserve may aid in early identification of survivors with heightened risk of long-term heart failure.

Cardiac Disease in Childhood Cancer Survivors: Risk Prediction, Prevention, and Surveillance: JACC CardioOncology State-of-the-Art Review

Cardiac diseases in the growing population of childhood cancer survivors are of major concern. Cardiotoxicity as a consequence of anthracyclines and chest radiotherapy continues to be relevant in the modern treatment era. Mitoxantrone has emerged as an important treatment-related risk factor and evidence on traditional cardiovascular risk factors in childhood cancer survivors is accumulating. International surveillance guidelines have been developed with the aim to detect and manage cardiac diseases early and prevent symptomatic disease. There is growing interest in risk prediction models to individualize prevention and surveillance. This State-of-the-Art Review summarizes literature from a systematic PubMed search focused on cardiac diseases after treatment for childhood cancer. Here, we discuss the prevalence, risk factors, prevention, risk prediction, and surveillance of cardiac diseases in survivors of childhood cancer.

Association of Exercise Intolerance With Emotional Distress, Attainment of Social Roles, and Health-Related Quality of Life Among Adult Survivors of Childhood Cancer

Importance

Exercise intolerance is associated with increased risk for morbidity and mortality in childhood cancer survivors. However, an association between exercise intolerance and psychosocial outcomes has not been fully explored.

Objective

To examine the associations between exercise intolerance and emotional distress, attainment of social roles, and health-related quality of life in childhood cancer survivors.

Design, Setting, and Participants

A cross-sectional study including 1041 adult survivors of childhood cancer and 286 community controls in the St Jude Lifetime Cohort was conducted at St Jude Children's Research Hospital. The study was performed from April 1, 2012, to March 15, 2020.

Exposures

Exercise intolerance was defined as relative peak oxygen uptake less than 85% of age- and sex-estimated levels from maximal cardiopulmonary exercise testing.

Main Outcomes and Measures

Emotional distress was measured with the 18-item Brief Symptom Inventory-18, which includes overall Global Severity Index and depression, anxiety, and somatization subscales. Participants with T scores greater than or equal to 63 were classified as having elevated levels of distress. Social attainment was evaluated using patient-reported educational, employment, and marital status. Health-related quality of life was examined with the Medical Outcomes Survey Short Form-36. Participants with T scores less than or equal to 40 were classified as reporting poor health-related quality of life.

Results

Of the 1041 participants, 528 were women (50.7%). The prevalence of exercise intolerance among survivors (mean [SD] age, 35.5 [9.2] years) was higher than that among controls (age, 34.5 [10.0] years) (survivors: 634 [60.9%] vs controls: 75 [26.2%], P < .001). After adjusting for age at diagnosis and cardiopulmonary exercise testing, sex, race/ethnicity, smoking, physical activity, and exercise intolerance were associated with an increased risk for anxiety (prevalence rate ratio [PRR], 1.95; 95% CI, 1.20-3.16), somatization (PRR, 1.86; 95% CI, 1.23-2.80), and unemployment (PRR, 1.76; 95% CI, 1.23-2.52); an inverse association was noted with having a college degree (PRR, 0.67; 95% CI, 0.50-0.88). Exercise intolerance was associated with an increased the risk for scoring less than or equal to 40 on the physical component summary of the Medical Outcomes Survey Short Form-36 (PRR, 3.69; 95% CI, 2.34-5.84). These associations persisted when either cancer treatment exposures or chronic health conditions were added to the model.

Conclusions and Relevance

The findings of this study suggest that exercise intolerance is independently associated with emotional distress, attainment of social roles, and health-related quality of life of long-term survivors of childhood cancer. The results also suggest that improving physiologic capacity may benefit general health and wellness, as well as emotional health, ability to participate in social roles, and health-related quality of life.

Effects of a physical activity program from diagnosis on cardiorespiratory fitness in children with cancer: a national non-randomized controlled trial

BACKGROUND

Children with cancer experience impaired cardiorespiratory fitness and physical function during and after treatment restricting their possibilities to engage in social activities including sport, leisure activities, and school. The objectives were to determine the effects of classmate-supported, controlled, supervised, in-hospital, physical activity program to preserve cardiorespiratory fitness and physical function from time of diagnosis in children with cancer.

METHODS

National non-randomized controlled trial including schoolchildren aged 6-18 years at diagnosis treated with chemo-/radiotherapy. We included 120 of 128 eligible patients (94%) in the intervention group (62.5% boys, 11.2 ± 3.1 years) from East Denmark and 58 patients in the control group (57% boys, 11.0 ± 3.2 years) from West Denmark. Eight children from the control group withdrew from participation. The groups were comparable in anthropometrics and cancer diagnoses (p > 0.05). The intervention consisted of (i) supervised in-hospital physical activity from diagnosis and throughout intensive treatment, (ii) 90-min general educational session on cancer and therapy in the child's school class, and (iii) selection of two classmates as ambassadors who took turns to support the child's physical training during the daytime. The primary outcome was cardiorespiratory fitness (VO₂peak, mL/min/kg) at 6 months after diagnosis (sex, age, diagnosis adjusted). Secondary outcomes were sit-to-stand, timed-up-and-go, handgrip strength, and balance test scores.

RESULTS

Ambassadors were identified for all, and 2542 individual and 621 group training sessions were held. VO₂peak deteriorated over time in the control group (- 0.17 [95% CI - 0.32 to - 0.02] per week, p = 0.02), but not in the intervention group (p = 0.14). At 6 months from diagnosis, VO₂peak was higher in the intervention group (29.6 ± 5.6 mL/kg/min) than in the control group (22.1 ± 5.6 mL/kg/min) (p = 0.01), and the intervention group had a better physical function at 3 and 6 months (p < 0.0001).

CONCLUSIONS

Peer-supported, supervised, in-hospital, physical activity is safe and feasible in children with cancer during treatment. Further, the results suggest that the intervention might mitigate impairments in cardiorespiratory fitness during treatment in children with cancer.

TRIAL REGISTRATION

The study was prospectively registered on the 11 January 2013. Clinicaltrial.gov NCT01772849 and NCT01772862 .

Maximal cardiopulmonary exercise testing in childhood acute lymphoblastic leukemia survivors exposed to chemotherapy

PURPOSE

The purpose of this study was to demonstrate if childhood acute lymphoblastic leukemia (ALL) survivors exposed to chemotherapy (i.e., doxorubicin) are able to achieve a safe maximal cardiopulmonary exercise test (CPET).

METHODS

A total of 250 childhood ALL survivors were eligible to undergo a CPET on ergocycle. Analyses were performed in 216 survivors and stratified in regard to their prognostic risk groups: 99 survivors (55 males and 44 females) at standard risk and 117 survivors (56 males and 61 females) at high risk.

RESULTS

Results showed that 100% (n = 216) of survivors completed a maximal CPET confirmed by the achievement of two out of three of the following criteria: 197 survivors (91.2%) reached a peak RER value of ≥ 1.15, 197 survivors (91.2%) reached a RPE score > 7, and 210 survivors (97.2%) reached a maximal heart rate ≥ 85% of the predicted value. Linear regression analysis showed a significant association between the survivors' cumulative dose of doxorubicin and their VO₂ peak measured. Two non-fatal adverse events were observed and reported at the end of the maximal CPET, while non-fatal adverse events were reported in 5 survivors during the recovery period. None of these events resulted in a long-term complication.

CONCLUSION

Childhood ALL survivors with prior exposure to chemotherapy can achieve a safe maximal CPET. They were able of achieving a maximal exercise test without being limited by symptoms, potential overprotection, or musculoskeletal issues. Thus, it should be the norm to realize a CPET prior a physical activity program to propose an optimal prescription. This study provides important information regarding the maximal physiological parameters that childhood ALL survivors are able to reach and have important clinical implications in the exercise and oncology field for this population of survivors.

Clinical Practice and Research in Cardio-Oncology: Finding the "Rosetta Stone" for Establishing Program Excellence in Cardio-oncology

The burgeoning field of cardio-oncology (C-O) is now necessary for the delivery of excellent care for patients with cancer. Many factors have contributed to this increasing population of cancer survivors or those being treated with novel and targeted cancer therapies. There is a tremendous need to provide outstanding cardiovascular (CV) care for these patients; however, current medical literature actually provides a paucity of guidance. C-O therefore provides a novel opportunity for clinical, translational, and basic research to advance patient care. This review aims to be a primer for cardio-oncologists on how to develop a vibrant and comprehensive C-O program, use practical tools to assist in the construction of C-O services, and to proactively incorporate translational and clinical research into the training of future leaders as well as enhance clinical care.

The Utility of Cardiac Reserve for the Early Detection of Cancer Treatment-Related Cardiac Dysfunction: A Comprehensive Overview

With progressive advancements in cancer detection and treatment, cancer-specific survival has improved dramatically over the past decades. Consequently, long-term health outcomes are increasingly defined by comorbidities such as cardiovascular disease. Importantly, a number of well-established and emerging cancer treatments have been associated with varying degrees of cardiovascular injury that may not emerge until years following the completion of cancer treatment. Of particular concern is the development of cancer treatment related cardiac dysfunction (CTRCD) which is associated with an increased risk of heart failure and high risk of morbidity and mortality. Early detection of CTRCD appears critical for preventing long-term cardiovascular morbidity in cancer survivors. However, current clinical standards for the identification of CTRCD rely on assessments of cardiac function in the resting state. This provides incomplete information about the heart's reserve capacity and may reduce the sensitivity for detecting sub-clinical myocardial injury. Advances in non-invasive imaging techniques have enabled cardiac function to be quantified during exercise thereby providing a novel means of identifying early cardiac dysfunction that has proved useful in several cardiovascular pathologies. The purpose of this narrative review is (1) to discuss the different non-invasive imaging techniques that can be used for quantifying different aspects of cardiac reserve; (2) discuss the findings from studies of cancer patients that have measured cardiac reserve as a marker of CTRCD; and (3) highlight the future directions important knowledge gaps that need to be addressed for cardiac reserve to be effectively integrated into routine monitoring for cancer patients exposed to cardiotoxic therapies.