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

Associations between mitochondrial copy number, exercise capacity, physiologic cost of walking, and cardiac strain in young adult survivors of childhood cancer

PURPOSE

Childhood cancer survivors are at risk for cardiac dysfunction and impaired physical performance, though underlying cellular mechanisms are not well studied. In this cross-sectional study, we examined the association between peripheral blood mitochondrial DNA copy number (mtDNA-CN, a proxy for mitochondrial function) and markers of performance impairment and cardiac dysfunction.

METHODS

Whole-genome sequencing, validated by quantitative polymerase chain reaction, was used to estimate mtDNA-CN in 1720 adult survivors of childhood cancer (48.5% female; mean age = 30.7 years, standard deviation (SD) = 9.0). Multivariable logistic regression was performed to evaluate the associations between mtDNA-CN and exercise intolerance, walking inefficiency, and abnormal global longitudinal strain (GLS), adjusting for treatment exposures, age, sex, and race and ethnicity.

RESULTS

The prevalence of exercise intolerance, walking inefficiency, and abnormal GLS among survivors was 25.7%, 10.7%, and 31.7%, respectively. Each SD increase of mtDNA-CN was associated with decreased odds of abnormal GLS (adjusted odds ratio (OR) = 0.88, p = 0.04) but was not associated with exercise intolerance (OR = 1.02, p = 0.76) or walking inefficiency (OR = 1.06, p = 0.46). Alkylating agent exposure was associated with increased odds of exercise intolerance (OR = 2.25, p < 0.0001), walking inefficiency (OR = 2.37, p < 0.0001), and abnormal GLS (OR = 1.78, p = 0.0002).

CONCLUSIONS

Increased mtDNA-CN is associated with decreased odds of abnormal cardiac function in childhood cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

These findings demonstrate a potential role for mtDNA-CN as a biomarker of early cardiac dysfunction in this population.

Cardiac Dysfunction and Exercise Tolerance in Patients after Complex Treatment for Cranial and Craniospinal Tumors in Childhood

State-of-the-art therapy improves the five-year survival rate of patients under the age of 20 with cranial and craniospinal tumors by up to 74%. The urgency of dealing effectively with late treatment-associated cardiovascular complications is rising. Objective: We aimed to assess echocardiographic parameters and exercise performance in subjects with a history of complex treatment for cranial and craniospinal tumors in childhood. Methods: the study of 48 subjects who underwent cranial and craniospinal irradiation for CNS tumors in childhood and 20 healthy age- and sex-matched volunteers was conducted. The examination included hormone studies, cardiopulmonary exercise testing, and, in the main group, echocardiography (ECHO). Results: In five (10.4%) patients, ECHO changes were detected after complex anti-cancer treatment: thickening and calcification of the aortic valve leaflets (2%), and reduction in the systolic LV and RV function (8% and 6%, respectively). Irradiation of various areas was a significant predictor for reduced exercise tolerance, hyperventilation at rest and upon exertion, and an increased ventilatory equivalent for carbon dioxide. Low exercise tolerance was associated with a younger age at the time of treatment initiation. Significant differences were noted between the control group and the childhood cancer survivors with endocrine disorders. Conclusions: The obtained data confirm the importance of regular cardiovascular and endocrine monitoring of this group of cancer survivors.

Mechanisms of Exercise Intolerance Across the Breast Cancer Continuum: A Pooled Analysis of Individual Patient Data

PURPOSE

The purpose of this study is to evaluate the prevalence of abnormal cardiopulmonary responses to exercise and pathophysiological mechanism(s) underpinning exercise intolerance across the continuum of breast cancer (BC) care from diagnosis to metastatic disease.

METHODS

Individual participant data from four randomized trials spanning the BC continuum ([1] prechemotherapy [n = 146], [2] immediately postchemotherapy [n = 48], [3] survivorship [n = 138], and [4] metastatic [n = 47]) were pooled and compared with women at high-risk of BC (BC risk; n = 64). Identical treadmill-based peak cardiopulmonary exercise testing protocols evaluated exercise intolerance (peak oxygen consumption; V̇O2peak) and other resting, submaximal, and peak cardiopulmonary responses. The prevalence of 12 abnormal exercise responses was evaluated. Graphical plots of exercise responses were used to identify oxygen delivery and/or uptake mechanisms contributing to exercise intolerance. Unsupervised, hierarchical cluster analysis was conducted to explore exercise response phenogroups.

RESULTS

Mean V̇O2peak was 2.78 ml O2.kg-1·min-1 (95% confidence interval [CI], -3.94, -1.62 mL O2.kg-1·min-1; P < 0.001) lower in the pooled BC cohort (52 ± 11 yr) than BC risk (55 ± 10 yr). Compared with BC risk, the pooled BC cohort had a 2.5-fold increased risk of any abnormal cardiopulmonary response (odds ratio, 2.5; 95% confidence interval, 1.2, 5.3; P = 0.014). Distinct exercise responses in BC reflected impaired oxygen delivery and uptake relative to control, although considerable inter-individual heterogeneity within cohorts was observed. In unsupervised, hierarchical cluster analysis, six phenogroups were identified with marked differences in cardiopulmonary response patterns and unique clinical characteristics.

CONCLUSIONS

Abnormal cardiopulmonary response to exercise is common in BC and is related to impairments in oxygen delivery and uptake. The identification of exercise response phenogroups could help improve cardiovascular risk stratification and guide investigation of targeted exercise interventions.

Lifestyle and Subsequent Malignant Neoplasms in Childhood Cancer Survivors: A Report from the St. Jude Lifetime Cohort Study

INTRODUCTION

This study aimed to assess longitudinal associations between lifestyle and subsequent malignant neoplasms (SMNs) in young adult childhood cancer survivors.

METHODS

Members of the St. Jude Lifetime Cohort (SJLIFE) aged ≥18 years and surviving ≥5 years after childhood cancer diagnosis were queried and evaluated for physical activity, cardiorespiratory fitness (CRF), muscle strength, body mass index (BMI), smoking, risky drinking, and a combined lifestyle score. Time to first SMN, excluding nonmalignant neoplasms and nonmelanoma skin cancer, was the outcome of longitudinal analysis.

RESULTS

Survivors (n = 4072, 47% female, 29% smokers, 37% risky drinkers, 34% obese, and 48% physically inactive) had a mean (SD) time between baseline evaluation and follow-up of 7.0 (3.3) years, an age of 8.7 (5.7) years at diagnosis, and an age of 30 (8.4) years at baseline lifestyle assessment. Neither individual lifestyle factors nor a healthy lifestyle score (RR 0.8, 0.4-1.3, p = 0.36) were associated with the risk of developing an SMN.

CONCLUSIONS

We did not identify any association between lifestyle factors and the risk of SMN in young adult childhood cancer survivors.

Movement efficiency in survivors of childhood acute lymphoblastic leukemia: a report from the St. Jude lifetime cohort study

PURPOSE

Movement efficiency, a measure of neuromuscular biomechanics, may be modified by physical activity. We aimed to assess the risk of and risk factors for low movement efficiency in survivors of childhood acute lymphoblastic leukemia (ALL).

METHODS

Participants underwent an assessment of activity energy expenditure (AEE) with actigraphy, and the gold standard doubly labeled water, where the differences between elimination rates of oxygen and hydrogen from body water are evaluated over a week. Movement efficiency was assessed using the raw residuals of a linear regression between AEEs from accelerometers and doubly labeled water. Elastic-net logistic regressions were used to identify demographic, treatment, and functional variables associated with movement efficiency.

RESULTS

The study cohort included 256 non-cancer controls and 302 ALL survivors (48% female), categorized as efficient (N = 24), normal (N = 245), or inefficient (N = 33) based on their movement efficiency. There was no difference in the odds for poor movement efficiency between survivors (n = 33, 10.9%) compared to controls (n = 23, 9.0%, odds ratio [OR]: 1.19, 95% confidence interval [CI]: 0.67, 2.10; p = 0.55). In survivors, neuropathy was associated with a higher risk of being inefficient compared to efficient (OR 4.30, 95% CI 1.03-17.96), while obesity (≥ 30 kg/m2) had a protective association (OR 0.18, 95% CI 0.04-0.87).

CONCLUSIONS

Neuropathy was associated with a higher risk of poor movement efficiency in survivors of childhood ALL.

IMPLICATIONS FOR CANCER SURVIVORS

These results further highlight impairments associated with treatment-induced neuropathy in survivors of childhood ALL.

Evaluation of Metabolic and Cardiovascular Risk Measured by Laboratory Biomarkers and Cardiopulmonary Exercise Test in Children and Adolescents Recovered from Brain Tumors: The CARMEP Study

In recent decades, the improvement of treatments and the adoption of therapeutic protocols of international cooperation has led to an improvement in the survival of children affected by brain tumors. However, in parallel with the increase in survival, long-term side effects related to treatments have been observed over time, including the activation of chronic inflammatory processes and metabolic alterations, which can facilitate the onset of metabolic syndrome and increased cardiovascular risk. The aim of this study was to find possible statistically significant differences in the serum concentrations of early biomarkers of metabolic syndrome and in the results of cardiopulmonary exercise testing between survivors of childhood brain tumors and healthy controls. This is a prospective and observational study conducted on a group of 14 male patients who survived childhood brain tumors compared with the same number of healthy controls. The concentrations of early metabolic syndrome biomarkers [adiponectin, leptin, TNF-α, IL-1, IL-6, IL-10, endothelin-1, apolipoprotein B, and lipoprotein (a)] were measured and a cardiopulmonary exercise test (CPET) was performed. Results: Childhood brain tumor survivors performed worse on average than controls on the CPET. Furthermore, they showed higher endothelin-1 values than controls (p = 0.025). The CPET results showed an inverse correlation with leptin. The differences found highlight the greater cardiovascular risk of brain tumor survivors, and radiotherapy could be implicated in the genesis of this greater cardiovascular risk.

Promoting positive physical activity behaviours in children undergoing acute cancer treatment: feasibility of the CanMOVE intervention

BACKGROUND

Supporting children and adolescents with cancer to be physically active can improve medium- and long-term health outcomes.

OBJECTIVE

To assess the feasibility of CanMOVE, a 10-week complex, theoretically-informed, behaviour change intervention to promote physical activity for children and adolescents undergoing acute cancer treatment.

METHODS

A feasibility study using a single-group, repeated measures, mixed methods design. Participants completed CanMOVE, which included provision of a Fitbit (child/adolescent and carer) and structured support from a physical therapist. Feasibility domains of demand, acceptability, implementation, practicality, limited efficacy, and integration were evaluated. Data sources included service level data, objective assessment of physical activity, physical function, and health-related quality of life; and qualitative data collected via semi-structured interviews with participants and focus groups with staff.

RESULTS

Twenty children/adolescents (median age 13yrs, interquartile-range 9-14) with a mix of cancer diagnoses, 20 parents, and 16 clinicians participated. There was high demand with 95% enrolment rate. CanMOVE was acceptable for participants. All feasibility thresholds set for implementation were met. Under practicality, there were no serious adverse events related to the intervention. Limited efficacy data indicated CanMOVE showed positive estimates of effect in influencing child/adolescent physical activity behaviour, physical function, and health-related quality of life. Positive impacts were also seen in parent and staff attitudes towards physical activity promotion. To improve integration into the clinical setting, it was suggested the duration and scope of CanMOVE could be expanded.

CONCLUSION

CanMOVE was feasible to implement in a paediatric cancer setting. CanMOVE is appropriate to be tested in a large-scale trial.

Children with cancer and their cardiorespiratory fitness and physical function-the long-term effects of a physical activity program during treatment: a multicenter non-randomized controlled trial

PURPOSE

We aimed to determine the effects of a classmate-supported, supervised, in-hospital physical activity program during treatment primarily on cardiorespiratory fitness and secondarily on physical function.

METHODS

A multicenter non-randomized controlled intervention study including children diagnosed with cancer, 6-18 years at diagnosis treated with chemo-/radiotherapy. The intervention comprised (i) an educational session on cancer in the child's school class; (ii) selection of two "ambassadors"-classmates who were co-admitted, supporting the child's everyday hospital life; and (iii) supervised in-hospital physical activity from diagnosis and throughout intensive treatment. One-year post-treatment, physical testing included cardiorespiratory fitness (primary outcome), Sit-to-Stand test, Timed-Up-and-Go, and Handgrip Strength.

RESULTS

The intervention group included 75 of 120 children (61% boys, 13.4 ± 3.1 years); the control groups included 33 of 58 children with cancer (58% boys, 13.5 ± 2.5 years), and 94 age- and sex-matched children without a cancer history. One-year post-treatment, cardiorespiratory fitness tended to be higher in the intervention group (37.0 ± 6.0 mL/kg/min) than in the patient control group with cancer (32.3 ± 9.7 mL/kg/min) (mean difference 4.7 [0.4 to 9.1], p = 0.034). The intervention group performed better in the secondary outcomes. Compared with community controls, both patient groups had lower cardiorespiratory fitness. The patient control group had lower Sit-to-Stand, Timed Up and Go, and Handgrip Strength, while the intervention group had strength comparable to that of the community controls.

CONCLUSIONS

Peer-supported, supervised, in-hospital physical activity during treatment may improve cardiorespiratory fitness and muscle strength 1-year post-treatment in children with cancer; however, survivors continue to have lower cardiorespiratory fitness than community controls.

IMPLICATIONS FOR CANCER SURVIVORS

Children with cancer may benefit from in-hospital physical activity in improving long-term cardiorespiratory fitness and muscle strength.

Surveillance cardiopulmonary exercise testing can risk-stratify childhood cancer survivors: underlying pathophysiology of poor exercise performance and possible room for improvement

BACKGROUND

Asymptomatic childhood cancer survivors (CCS) frequently show decreased exercise performance. Poor exercise performance may indicate impaired future cardiovascular health.

METHODS

Cardiopulmonary exercise testing (CPET) was performed in asymptomatic off-treatment CCS (age ≥ 10 years). Patients were divided into Normal and Poor performance groups by %predicted maximum VO2 at 80%. Both peak and submaximal CPET values were analyzed.

RESULTS

Thirty-eight males (19 Normal, 19 Poor) and 40 females (18 Normal, 22 Poor) were studied. Total anthracycline dosage was comparable among 4 groups. The body mass index (BMI), although normal, and weight were significantly higher in Poor groups. Peak heart rate (HR) and peak respiratory exchange ratio (RER) were comparable in all four groups. Peak work rate (pWR)/kg, peak oxygen consumption (pVO2)/kg, peak oxygen pulse (pOP)/kg, and ventilatory anaerobic threshold (VAT)/kg were significantly lower, whereas heart rate (HR) increase by WR/kg (ΔHR/Δ[WR/kg] was significantly higher in Poor groups. Simultaneously plotting of weight & pVO2 and ΔHR/ΔWR & ΔVO2/ΔHR revealed a distinct difference between the Normal and Poor groups in both sexes, suggesting decreased skeletal muscle mass and decreased stroke volume reserve, respectively, in Poor CCS. The relationship between VAT and pVO2 was almost identical between the two groups in both sexes. Ventilatory efficiency was mildly diminished in the Poor groups.

CONCLUSIONS

Decreased skeletal muscle mass, decreased stroke volume reserve, and slightly decreased ventilatory efficiency characterize Poor CCS in both sexes. This unique combined CPET analysis provides useful clinical biomarkers to screen subclinical cardiovascular abnormality in CCS and identifies an area for improvement.

Cancer survivorship at heart: a multidisciplinary cardio-oncology roadmap for healthcare professionals

In cancer, a patient is considered a survivor from the time of initial diagnosis until the end of life. With improvements in early diagnosis and treatment, the number of cancer survivors (CS) has grown considerably and includes: (1) Patients cured and free from cancer who may be at risk of late-onset cancer therapy-related cardiovascular toxicity (CTR-CVT); (2) Patients with long-term control of not-curable cancers in whom CTR-CVT may need to be addressed. This paper highlights the importance of the cancer care continuum, of a patient-centered approach and of a prevention-oriented policy. The ultimate goal is a personalized care of CS, achievable only through a multidisciplinary-guided survivorship care plan, one that replaces the fragmented management of current healthcare systems. Collaboration between oncologists and cardiologists is the pillar of a framework in which primary care providers and other specialists must be engaged and in which familial, social and environmental factors are also taken into account.

Predictors of lower exercise capacity in patients with cancer

Maintaining cancer patients' exercise capacity and therefore patients' ability to live a self-determined life is of huge importance, but little is known about major determinants. We sought to identify determinants of exercise capacity in patients with a broad spectrum of cancer types, who were already receiving cancer treatment or about to commence such therapy. Exercise capacity was assessed in 253 consecutive patients mostly suffering from advanced cancer using the 6-min walk test (6-MWT). All patients underwent echocardiography, physical examination, resting electrocardiogram, hand grip strength (HGS) measurement, and laboratory assessments. Patients were divided into two groups according to the median distance in the 6-MWT (459 m). Patients with lower exercise capacity were older, had significantly lower HGS and haemoglobin and higher values of high sensitive (hs) Troponin T and NT-proBNP (all p < 0.05). Whilst the co-morbidity burden was significantly higher in this group, no differences were detected for sex, body mass index, tumor type, or cachexia (all p > 0.2). Using multivariable logistic regression, we found that the presence of anaemia (odds ratio (OR) 6.172, 95% confidence interval (CI) 1.401-27.201, p = 0.016) as well as an increase in hs Troponin T (OR 3.077, 95% CI 1.202-5.301, p = 0.019) remained independent predictors of impaired exercise capacity. Increasing HGS was associated with a reduced risk of a lower exercise capacity (OR 0.896, 95% CI 0.813-0.987, p = 0.026). Screening patients for elevated hs troponin levels as well as reduced HGS may help to identify patients at risk of lower exercise capacity during cancer treatment.

Substrate oxidation during exercise in childhood acute lymphoblastic leukemia survivors

Children with acute lymphoblastic leukemia (ALL) are at high risk of developing long-term cardiometabolic complications during their survivorship. Maximal fat oxidation (MFO) is a marker during exercise of cardiometabolic health, and is associated with metabolic risk factors. Our aim was to characterize the carbohydrate and fat oxidation during exercise in childhood ALL survivors. Indirect calorimetry was measured in 250 childhood ALL survivors to quantify substrate oxidation rates during a cardiopulmonary exercise test. A best-fit third-order polynomial curve was computed for fat oxidation rate (mg/min) against exercise intensity (%V ̇ O2peak) and was used to determine the MFO and the peak fat oxidation (Fatmax). The crossover point was also identified. Differences between prognostic risk groups were assessed (ie, standard risk [SR], high risk with and without cardio-protective agent dexrazoxane [HR + DEX and HR]). MFO, Fatmax and crossover point were not different between the groups (p = .078; p = .765; p = .726). Fatmax and crossover point were achieved at low exercise intensities. A higher MFO was achieved by men in the SR group (287.8 ± 111.2 mg/min) compared to those in HR + DEX (239.8 ± 97.0 mg/min) and HR groups (229.3 ± 98.9 mg/min) (p = .04). Childhood ALL survivors have low fat oxidation during exercise and oxidize carbohydrates at low exercise intensities, independently of the cumulative doses of doxorubicin they received. These findings alert clinicians on the long-term impact of cancer treatments on childhood ALL survivors' substrate oxidation.

Simultaneous exercise stress cardiac magnetic resonance and cardiopulmonary exercise testing to elucidate the Fick components of aerobic exercise capacity: a feasibility and reproducibility study and pilot study in hematologic cancer survivors

BACKGROUND

Patients treated for hematologic malignancy often experience reduced exercise capacity and increased fatigue; however whether this reduction is related to cardiac dysfunction or impairment of skeletal muscle oxygen extraction during activity is unknown. Cardiopulmonary exercise testing (CPET) coupled with stress cardiac magnetic resonance (ExeCMR), may provide a noninvasive method to identify the abnormalities of cardiac function or skeletal muscle oxygen extraction. This study was performed to determine the feasibility and reproducibility of a ExeCMR + CPET technique to measure the Fick components of peak oxygen consumption (VO2) and pilot its discriminatory potential in hematologic cancer patients experiencing fatigue.

METHODS

We studied 16 individuals undergoing ExeCMR to determine exercise cardiac reserve with simultaneous measures of VO2. The arteriovenous oxygen content difference (a-vO2diff) was calculated as the quotient of VO2/cardiac index (CI). Repeatability in measurements of peak VO2, CI, and a-vO2diff was assessed in seven healthy controls. Finally, we measured the Fick determinants of peak VO2 in hematologic cancer survivors with fatigue (n = 6) and compared them to age/gender-matched healthy controls (n = 6).

RESULTS

Study procedures were successfully completed without any adverse events in all subjects (N = 16, 100%). The protocol demonstrated good-excellent test-retest reproducibility for peak VO2 (intraclass correlation coefficient [ICC] = 0.992 [95%CI:0.955-0.999]; P < 0.001), peak CI (ICC = 0.970 [95%CI:0.838-0.995]; P < 0.001), and a-vO2diff (ICC = 0.953 [95%CI:0.744-0.992]; P < 0.001). Hematologic cancer survivors with fatigue demonstrated a significantly lower peak VO2 (17.1 [13.5-23.5] vs. 26.0 [19.7-29.5] mL·kg-1·min-1, P = 0.026) and lower peak CI (5.0 [4.7-6.3] vs. 7.4 [7.0-8.8] L·min-1/m2, P = 0.004) without a significant difference in a-vO2diff (14.4 [11.8-16.9] vs. 13.6 [10.9-15.4] mLO2/dL, P = 0.589).

CONCLUSIONS

Noninvasive measurement of peak VO2 Fick determinants is feasible and reliable with an ExeCMR + CPET protocol in those treated for a hematologic malignancy and may offer insight into the mechanisms of exercise intolerance in those experiencing fatigue.

Systolic myocardial function measured by echocardiographic speckle-tracking and peak oxygen consumption in pediatric childhood cancer survivors-a PACCS study

Background

Cancer therapy-related cardiotoxicity is a major cause of cardiovascular morbidity in childhood cancer survivors. The aims of this study were to investigate systolic myocardial function and its association to cardiorespiratory fitness in pediatric childhood cancer survivors.

Methods

In this sub-study of the international study "Physical Activity and fitness in Childhood Cancer Survivors" (PACCS), echocardiographic measures of left ventricular global longitudinal strain (LV-GLS) and right ventricular longitudinal strain (RV-LS) were measured in 128 childhood cancer survivors aged 9-18 years and in 23 age- and sex-matched controls. Cardiorespiratory fitness was measured as peak oxygen consumption achieved on treadmill and correlated to myocardial function.

Results

Mean LV-GLS was reduced in the childhood cancer survivors compared to the controls, -19.7% [95% confidence interval (CI) -20.1% to -19.3%] vs. -21.3% (95% CI: -22.2% to -20.3%) (p = 0.004), however, mainly within normal range. Only 13% of the childhood cancer survivors had reduced LV longitudinal strain z-score. Mean RV-LS was similar in the childhood cancer survivors and the controls, -23.2% (95% CI: -23.7% to -22.6%) vs. -23.3% (95% CI: -24.6% to -22.0%) (p = 0.8). In the childhood cancer survivors, lower myocardial function was associated with lower peak oxygen consumption [correlation coefficient (r) = -0.3 for LV-GLS]. Higher doses of anthracyclines (r = 0.5 for LV-GLS and 0.2 for RV-LS) and increasing time after treatment (r = 0.3 for LV-GLS and 0.2 for RV-LS) were associated with lower myocardial function.

Conclusions

Left ventricular function, but not right ventricular function, was reduced in pediatric childhood cancer survivors compared to controls, and a lower left ventricular myocardial function was associated with lower peak oxygen consumption. Furthermore, higher anthracycline doses and increasing time after treatment were associated with lower myocardial function, implying that long-term follow-up is important in this population at risk.

Physical Inactivity as an Early Sign of Frailty in Young Adult Survivors of Childhood Acute Lymphoblastic Leukemia

Young adult survivors of childhood leukemia have been reported with increased likelihood of age-related comorbidities compared with the general population. We compared the prevalence of frailty in young adult survivors of childhood acute lymphoblastic leukemia (n=58, median age=23 y, median survival time=18 y) with age-matched and sex-matched controls without history of cancer. Frailty phenotypes were determined using Fried frailty model. Association between frailty status and cardiometabolic conditions, systemic inflammation, and T-cell immunophenotype changes were also examined. Frailty and prefrailty were more common among survivors compared with controls (58.6% vs. 34.5%, P =0.019). Physical inactivity (39.7%) was the most frequently observed frailty criterion among the survivors. Prevalence of cardiometabolic conditions was comparable between the robust and frail/prefrail survivors. Robust survivors had a higher level of T-cell activation than the prefrail/frail survivors ( P <0.05), but no significant difference was observed for systemic inflammatory markers (IL-6 and C-reactive protein) and percentage of terminally differentiated T cells. Signs of frailty, especially physical inactivity, was detected in childhood acute lymphoblastic leukemia survivors early in their third decade of life. Survivors who were prefrail/frail also had altered T-cell activation; however, the role of such changes in T-cell phenotype in the etiology of frailty warrant further investigation.

Cardio-oncology for Pediatric and Adolescent/Young Adult Patients

OPINION STATEMENT

As chemotherapy continues to improve the lives of patients with cancer, understanding the effects of these drugs on other organ systems, and the cardiovascular system in particular, has become increasingly important. The effects of chemotherapy on the cardiovascular system are a major determinant of morbidity and mortality in these survivors. Although echocardiography continues to be the most widely used modality for assessing cardiotoxicity, newer imaging modalities and biomarker concentrations may detect subclinical cardiotoxicity earlier. Dexrazoxane continues to be the most effective therapy for preventing anthracycline-induced cardiomyopathy. Neurohormonal modulating drugs have not prevented cardiotoxicity, so their widespread, long-term use for all patients is currently not recommended. Advanced cardiac therapies, including heart transplant, have been successful in cancer survivors with end-stage HF and should be considered for these patients. Research on new targets, especially genetic associations, may produce treatments that help reduce cardiovascular morbidity and mortality.

Functional Impairment in Pediatric Cancer Survivorship

Care for pediatric cancer survivors must include scheduled, thorough evaluations of potential chronic and late effects resulting from multidimensional cancer treatments. Assessment of functional independence with activities and participation is critical in assuring that survivors can optimally access their environments and pursue educational, occupational, and leisure activities appropriate to their interests and capabilities. Owing to their expertise in both rehabilitation and habilitation, pediatric physiatrists are of great benefit in the care of survivors of pediatric cancer.

Part 1: The Clinical Applications of Left Ventricular Myocardial Strain

There is an increasing prevalence of cardiovascular disease and heart failure. Indices of left ventricular (LV) systolic function such as LV ejection fraction used to identify those at risk of adverse cardiac events such as heart failure may not be truly representative of LV systolic function in certain cardiac diseases. Given that LV ejection fraction reduction may represent more advanced irreversible stages of disease, measures of myocardial strain have emerged as a feasible and robust instrument for the early identification of heart disease and subtle LV systolic dysfunction. The purpose of this review was to provide an overview of myocardial strain concepts and emerging clinical applications of global longitudinal strain in cardio-oncology.

Childhood Cancer Survivors Have Impaired Strain-Derived Myocardial Contractile Reserve by Dobutamine Stress Echocardiography

Abnormal left ventricular contractile reserve (LVCR) is associated with adverse cardiac outcomes in different patient cohorts and might be useful in the detection of cardiomyopathy in childhood cancer survivors (CCS) after cardiotoxic treatment. The aim of this study was to evaluate LVCR by dobutamine stress echocardiography (DSE) combined with measures of myocardial strain in CCS previously treated with anthracyclines (AC). Fifty-three CCS (age 25.34 ± 2.44 years, 35 male) and 53 healthy controls (age 24.40 ± 2.40 years, 32 male) were included. Subjects were examined with echocardiography at rest, at low-dose (5 micrograms/kg/min), and at high-dose (40 micrograms/kg/min) dobutamine infusion. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS), strain rate (GSR), and early diastolic strain rate (GEDSR) at different DSE phases were used as measures of LVCR. The mean follow-up time among CCS was 15.8 ± 5.8 years. GLS, GSR, and LVEF were lower at rest in CCS compared to controls (p ≤ 0.03). LVEF was within the normal range in CCS. ΔGLS, ΔGSR, and ΔGEDSR but not ΔLVEF were lower in CCS compared to controls after both low- (p ≤ 0.048) and high-dose dobutamine infusion (p ≤ 0.023). We conclude that strain measures during low-dose DSE detect impaired myocardial contractile reserve in young CCS treated with AC at 15-year follow-up. Thus, DSE may help identify asymptomatic CCS at risk for heart failure and allows for tailored follow-up accordingly.

Safety, Feasibility and Efficacy of Lokomat® and Armeo®Spring Training in Deconditioned Paediatric, Adolescent and Young Adult Cancer Patients

BACKGROUND

Rehabilitation robotics is a field of study which aims to understand and augment rehabilitation through the use of robotics devices.

OBJECTIVE

This proof of concept study aimed to test the safety (no. adverse events, incidence of infection), feasibility (program demand, adherence, participant satisfaction) and efficacy (Peak Oxygen uptake (VO_2peak), 6-min walk test, gait speeds, Canadian Occupational Performance Measure, quality of life) of Lokomat^® and Armeo^®Spring training in children and adolescents and young adults (AYAs) during or soon after cancer treatment.

METHOD

This was a 6-week single arm pre-post study. Cancer patients with significant musculoskeletal, neurological, gait and/or upper limb deficiency aged 5 to 25 years were recruited. The rehabilitation program included access to two robotic orthoses: the Lokomat^® and/or Armeo^®Spring. Robotic devices utilised real-time biofeedback and computer games to engage and guide participants through a repetitive functional range of movement aimed at improving functional deficiencies. Progressive increases in exercise intensity and duration were encouraged.

RESULTS

Twentey-eight participants were approached for study; twenty-one consented. Seventy-six percent completed the six-week intervention with an overall adherence of 83%. The mean participant satisfaction score was 8.8/10. Forty-nine adverse events were recorded throughout the course of the study, forty-five grade 1, three grade 2 and one grade 3. No adverse events led to withdrawal from the study. Preliminary efficacy results indicate large beneficial effects on VO_2peak (r = 0.63), 10 m comfortable pace walk (r = 0.51) and maximal pace walk (r = 0.60), 6-min walk test (r = 0.60), maximal back and leg strength (r = 0.71), trunk flexibility (r = 0.60), The European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C30) (r = 0.61), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT F) r = 0.53 and the Canadian Occupational Performance Measure, satisfaction (r = 0.88) and performance scores (r = 0.83), and moderate beneficial effects on Leisure Score Index (LSI) (r = 0.30).

CONCLUSION

Our results suggest that Lokomat^® and Armeo^®Spring training is safe and feasible for use in children and AYAs who are currently undergoing or have recently completed cancer therapy. A larger controlled trial investigating the efficacy of robotics rehabilitation in this cohort is warranted.

Cardiopulmonary Exercise Testing Characterizes Silent Cardiovascular Abnormalities in Asymptomatic Pediatric Cancer Survivors

Late-onset cardiovascular complications are serious concerns for pediatric cancer survivors (PCS) including those who are asymptomatic. We investigated whether cardiopulmonary exercise testing (CPET) can delineate the underlying pathophysiology of preclinical cardiovascular abnormalities in PCS. We examined CPET data via cycle ergometer in asymptomatic PCS with normal echocardiogram and age-matched controls. Peak and submaximal parameters were analyzed. Fifty-three PCS and 60 controls were studied. Peak oxygen consumption (VO₂), peak work rate (WR), and ventilatory anaerobic threshold (VAT) were significantly lower in PCS than controls (1.86 ± 0.53 vs. 2.23 ± 0.61 L/min, 125 ± 45 vs. 154 ± 46 W, and 1.20 ± 0.35 vs. 1.42 ± 0.43 L/min, respectively; all p < 0.01), whereas peak heart rate (HR) and ventilatory efficiency (a slope of minute ventilation over CO₂ production or ∆VE/∆VCO₂) were comparable. Peak respiratory exchange ratio (RER) was significantly higher in PCS (p = 0.0006). Stroke volume (SV) reserve was decreased in PCS, indicated by simultaneous higher dependency on HR (higher ∆HR/∆WR) and lower peak oxygen pulse (OP). Twelve PCS with high peak RER (≥ 1.3) revealed lower pVO₂ and VAT than the rest of PCS despite higher ventilatory efficiency (lower ∆VE/∆VCO₂), suggesting fundamental deficiency in oxygen utilization in some PCS. Poor exercise performance in PCS may be mainly attributed to limited stroke volume reserve, but the underlying pathophysiology is multifactorial. Combined assessment of peak and submaximal CPET parameters provided critical information in delineating underlying exercise physiology of PCS.

Reduced exercise capacity is associated with left ventricular systolic dysfunction in long-term survivors of allogeneic hematopoietic stem-cell transplantation

PURPOSE

Exercise intolerance is a common complication in survivors of allogeneic hematopoietic stem-cell transplantation (allo-HSCT). The aim of this study was to determine if cardiac function measured with echocardiography is associated with exercise capacity measured with cardio-pulmonary exercise tests in long-term survivors treated in their youth with allo-HSCT.

METHODS

The study included 96 patients, of which 54.2% were female, aged 34.9 ± 11.6 years and 17.7 ± 9.3 years after allo-HSCT. Reduced exercise capacity was defined as <85% of predicted-peak oxygen uptake (VO_2peak ). Linear regression was used in the prediction of VO_2peak (ml/kg/min). Receiver operating characteristic evaluated the accuracy of predicting reduced exercise capacity.

RESULTS

VO_2peak was 36.2 ± 7.7 ml/kg/min and 43 (44.8%) had reduced exercise capacity. Left ventricular ejection fraction was 55.4 ± 5.9% and global longitudinal strain (GLS) was -17.6% ± 2.0%. Left and right ventricular functions were significantly lower in survivors with reduced exercise capacity. Increased body mass index, lower physical activity score, reduced pulmonary function (by forced expiratory volume in 1-s) and reduced left ventricular systolic function (by GLS) were significant independent predictors for reduced VO_2peak . GLS was superior to other echocardiographical indices for identifying reduced exercise capacity (area under curve = 0.64, p = 0.014).

CONCLUSIONS

Left ventricular systolic dysfunction measured by GLS is associated with reduced exercise capacity in long-term allo-HSCT survivors.

Perceived barriers and facilitators to physical activity in childhood cancer survivors and their parents: A large-scale interview study from the International PACCS Study

BACKGROUND

Physical activity (PA) may reduce risks of late effects in childhood cancer survivors, yet many have low activity levels. Using the WHO's International Classification of Functioning, Disability, and Health for Children and Youths (ICF-CY) as a conceptual framework, we aimed to identify perceived barriers and facilitators to PA in young survivors and their parents.

DESIGN/METHODS

We conducted individual, semi-structured interviews with 63 survivors, aged 9-18 years, ≥1-year off treatment, and 68 parents, recruited from three pediatric oncology departments in Norway and Denmark. Interviews were analyzed inductively using thematic analysis to identify barriers and facilitators to PA, which were mapped onto the ICF-CY model components; body function/structures, activities, participation, and environmental and personal factors.

RESULTS

Two-thirds of the survivors described how treatment-related impairments of bodily functions (e.g., fatigue, physical weakness, reduced lung capacity) caused physical limitations, reducing opportunities to participate in PA, especially team sports and school physical education. This resulted in a perceived ability gap between survivors and peers, reducing motivation for PA. These PA barriers were moderated by environmental factors that facilitated or further hindered PA participation (family, peer, and school support). Similarily, personal factors also facilitated (acceptance, motivation, goal setting) or hindered (anxiety, low motivation, and lack of trust) PA participation.

CONCLUSION

Treatment-related long-term or late effects represented significant barriers to PA as their functional consequences reduced survivors' capacities and capabilities to be active. Environmental and personal factors acting as facilitators or further barriers to PA were identified. Applying the ICF-CY framework in clinical practice could help to enable PA participation.

Adherence and Barriers to Inpatient Physical Therapy Among Adolescents and Young Adults with Hematologic Malignancies

This study described inpatient physical therapy (PT) adherence and barriers to inpatient PT among adolescents and young adults (AYAs) with hematologic malignancies receiving care at a Midwestern children's hospital. Forty-seven AYAs receiving care over a 2-year period were included. PT contact was established in 93% of hospitalizations. AYAs declined an average of 34% of PT visits, resulting in PT visits on 27% of hospitalized days, 1 day less than the goal of 3 days a week. The most frequent reasons for decline included: AYA sleeping (22%), AYA undergoing medical procedure (18%), and AYA not feeling well (12%).

Associations between exercise capacity, p16INK4a expression and inflammation among adult survivors of childhood cancer

BACKGROUND

Over 50% of childhood cancer survivors are exercise intolerant, with maximal aerobic capacities comparable to individuals decades older, suggesting early physiologic ageing. In addition, 36% of survivors are obese. Optimal exercise capacity provides a foundation to support daily function and healthy body habitus and is associated with benefits to cognition, cardiovascular health, and longevity. Cellular senescence and inflammation are key mechanisms that drive age-related disease, quantifiable as biomarkers in peripheral blood.

AIMS

This study aimed to evaluate associations between p16INKa, a biomarker of cellular senescence, and inflammation and exercise capacity among adult survivors of childhood cancer.

MATERIALS AND METHODS

Eligible survivors were recruited from the St. Jude Lifetime (SJLIFE) Cohort Study. Exercise capacity was assessed by maximal oxygen uptake (VO2, ml/kg/min) obtained via cardiopulmonary exercise testing using a modified Bruce protocol. Body fat (%) was determined from dual energy x-ray absorptiometry (DEXA). Peripheral blood samples were used to evaluate log2 p16INK4a mRNA expression, a biomarker of cellular senescence, and inflammation with high sensitivity C-reactive protein (hs-CRP) levels. Multivariable regression evaluated associations between p16INK4a, hs-CRP, body fat, and exercise capacity.

RESULTS

Participants included 185 five-year childhood cancer survivors (mean age 36.6 [range 20.1 - 55.7] years, 44% male, 77% non-Hispanic white, 53% leukemia/lymphoma). Compared to males, females had lower peak VO2 (mean ± SD, 22.5 ± 8.2 vs. 28.8 ± 7.7 ml/kg/min, p<0.01), higher p16INK4a expression (9.6 ± 1.2 vs. 9.2 ± 1.2 fold, p=0.02), and hs-CRP concentration (5.9 ± 8.4 vs. 3.3 ± 3.9 mg/L, p=0.01). Among females (n=103), hs-CRP concentration (β -0.2, 95% CI -0.34 to -0.05, p=0.01) and p16INK4a expression (β-5.32, 95% CI 10.42 to -0.22, p=0.04) were inversely associated and statistically significant with peak exercise capacity, with a significant interaction between p16INK4a expression and body fat (β 0.15, 95% CI 0.02 to 0.28, p=0.03). Among males (n=82), p16INK4a expression (β -1.01, 95% CI -2.14 to 0.12, p=0.08), and body fat (β -0.54, 95% CI -0.70 to -0.38, p<0.01) were inversely associated with peak exercise capacity.

CONCLUSION

Inflammation and p16INK4a expression, a biomarker of cellular senescence, are associated with lower exercise capacity in childhood cancer survivors, suggesting potential targets or outcome measures for interventions designed to prevent or remediate accelerated physiologic ageing in this population.

Inflammatory biomarkers after an exercise intervention in childhood acute lymphoblastic leukemia survivors

Cancer survivors show increased risk for non-communicable diseases and chronic low-grade inflammation characterizes the development of such diseases. We investigated inflammatory plasma protein profiles of survivors of childhood acute lymphoblastic leukemia (ALL) in comparison to healthy controls and after an intervention with a home-based exercise program. Survivors of childhood ALL aged 16-30 years (n = 21) with a median age at diagnosis 4.9 (1.6-12.9) years and a median time of 15.9 years from diagnosis, and sex- and age-matched healthy controls (n = 21) were studied. Stored plasma samples were analyzed with Olink's 92-protein-wide Inflammation panel in 21 ALL long-term survivors at baseline, after a previous 16-week home-based exercise intervention (n = 17) and in 21 age- and sex-matched controls at baseline. Protein expression levels were compared between the groups. Inflammatory protein levels did not differ between the survivors and controls at baseline. Significantly reduced levels after the intervention were found in 11 proteins related to either vascular inflammation, insulin resistance, or both: tumor necrosis factor superfamily member 14 (TNFSF14), oncostatin M (OSM), monocyte chemoattractant protein 1 (MCP-1), MCP-2, fibroblast growth factor 21 (FGF-21), chemokine (C-C motif) ligand 4 (CCL4), transforming growth factor alpha (TGF-α), tumor necrosis factor-related apoptosis-inducing ligand 10 (TRAIL), adenosine deaminase (ADA), chemokine (C-X-C motif) ligand 6 (CXCL6), and latency-associated peptide transforming growth factor beta 1 (LAP TGF-β1). The ALL survivors were not significantly more affected by inflammation than controls at baseline. The survivors' 16-week exercise intervention led to significant reduction in inflammatory protein levels. Physical exercise should be promoted for survivors of childhood cancer.

Exercise Intolerance in Facioscapulohumeral Muscular Dystrophy

PURPOSE

Determine 1) if adults with facioscapulohumeral muscular dystrophy (FSHD) exhibit exercise intolerance and 2) potential contributing mechanisms to exercise intolerance, specific to FSHD.

METHODS

Eleven people with FSHD (47 ± 13 yr, 4 females) and 11 controls (46 ± 13 yr, 4 females) completed one visit, which included a volitional peak oxygen consumption (V̇O2peak) cycling test. Breath-by-breath gas exchange, ventilation, and cardiovascular responses were measured at rest and during exercise. The test featured 3-min stages (speed, 65-70 rpm) with incremental increases in intensity (FSHD: 20 W per stage; control: 40-60 W per stage). Body lean mass (LM (kg, %)) was collected via dual-energy x-ray absorptiometry.

RESULTS

V̇O2peak was 32% lower (24.5 ± 9.7 vs 36.2 ± 9.3 mL·kg-1·min-1, P < 0.01), and wattage was 55% lower in FSHD (112.7 ± 56.1 vs 252.7 ± 67.7 W, P < 0.01). When working at a relative submaximal intensity (40% of V̇O2peak), wattage was 55% lower in FSHD (41.8 ± 30.3 vs 92.7 ± 32.6 W, P = 0.01), although ratings of perceived exertion (FSHD: 11 ± 2 vs control: 10 ± 3, P = 0.61) and dyspnea (FSHD: 3 ± 1 vs control: 3 ± 2, P = 0.78) were similar between groups. At an absolute intensity (60 W), the rating of perceived exertion was 63% higher (13 ± 3 vs 8 ± 2, P < 0.01) and dyspnea was 180% higher in FSHD (4 ± 2 vs 2 ± 2, P < 0.01). V̇O2peak was most strongly correlated with resting O2 pulse in controls (P < 0.01, r = 0.90) and percent leg LM in FSHD (P < 0.01, r = 0.88). Among FSHD participants, V̇O2peak was associated with self-reported functionality (FSHD-HI score; activity limitation: P < 0.01, r = -0.78), indicating a strong association between perceived and objective impairments.

CONCLUSIONS

Disease-driven losses of LM contribute to exercise intolerance in FSHD, as evidenced by a lower V̇O2peak and elevated symptoms of dyspnea and fatigue during submaximal exercise. Regular exercise participation may preserve LM, thus providing some protection against exercise tolerance in FSHD.

Insights into muscle stem cell dynamics during postnatal development

During development, resident stem cell populations contribute to the growth and maturation of tissue and organs. In skeletal muscle, muscle stem cells, or satellite cells (SCs), are responsible for the maturation of postnatal myofibers. However, the role SCs play in later stages of postnatal growth, and thus, when they enter a mature quiescent state is controversial. Here, we discuss the current literature regarding the role SCs play in all stages of postnatal growth, from birth to puberty onset to young adulthood. We additionally highlight the implications of SC loss or dysfunction during developmental stages, both in the context of experimental paradigms and disease settings.

Exploring relationships between inspiratory muscle strength and functional capacity in childhood cancer survivors: a pilot study

Childhood cancer survivors (CCS) experience short- and long-term side effects from cancer treatment that often impair functional capacity. Inspiratory muscle weakness is a potential mechanism for reduced functional capacity. The objective of this pilot study was to examine the relationship between inspiratory muscle strength and functional capacity in 10 CCS. Inspiratory muscle strength was measured by maximal inspiratory pressure (MIP) while functional capacity was measured by the two-minute walk test (2MWT), the physiological cost index and hemodynamic response to exercise according to changes in heart rate, blood pressure and rate-pressure product (RPP). Overall, MIP and 2MWT distance were below predicted values. Hemodynamic responses to the 2MWT were consistent with little variation, except for elevated diastolic blood pressure (DBP) response. MIP had significant relationships with resting DBP (Spearman's rank correlation coefficient [r_s] = -0.70; p = 0.03) and DBP response (r_s = 0.72; p = 0.02). Time since completion of cancer treatment had a significant positive relationship with RPP response (r_s = 0.67; p = 0.03). Inspiratory muscle weakness in childhood cancer could be an indicator of skeletal muscle dysfunction and should be considered when symptoms of dyspnea or poor functional capacity arise. Inspiratory muscle strength was found to be related to changes in blood pressure in CCS. Future studies should further investigate these relationships and the impact of inspiratory muscle training on hemodynamics and functional capacity in CCS.

Myocardial Deformation Imaging by Speckle Tracking Echocardiography for Assessment of Cardiotoxicity in Children During and After Chemotherapy: A Systematic Review and Meta-analysis

BACKGROUND

Childhood cancer patients and childhood cancer survivors (CCS) are at risk of developing chemotherapy-induced cardiomyopathy. Myocardial deformation imaging has shown potential in the early detection of subclinical myocardial damage with implications on therapeutic interventions and improvement of outcomes. We aimed to perform a systemic review and meta-analysis of literature on the assessment of left (LV) and right ventricular (RV) myocardial deformation by speckle tracking echocardiography (STE) at rest and during stress in childhood cancer patients during and in survivors after chemotherapy.

METHODS

A systematic review was performed through searching MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, and Scopus. Search hedges were created to cover the concepts of childhood cancer, chemotherapy, radiotherapy, anthracycline, cardiotoxicity, speckle tracking, myocardial strain, and myocardial deformation. Two independent investigators reviewed the eligibility of the articles for inclusion. Weighted mean difference in ventricular strain between pre-and post-chemotherapy treatment and that between long-term CCS and healthy subjects were estimated by random-effect models with 95% confidence intervals. Heterogeneity and publication bias were assessed by I2 statistics and Egger test, respectively.

RESULTS

Of the total of 8703 records initially identified, 42 studies with a total of 430 childhood cancer patients were included. Of these 42 studies that showed heterogeneities, 9 assessed early myocardial injury during chemotherapy, 30 assessed late myocardial injury after chemotherapy with no publication bias, and 3 studied myocardial mechanics during stress. The main findings were 1) impairment of LV systolic deformation in childhood cancer patients during the initial treatment phase and among long-term CCS, while data on changes in RV deformation are limited and inconclusive, 2) the predictive value of early reduction of myocardial strain imaging in forecasting subsequent development of cardiotoxicity is unknown as it has not been studied, 3) limited data suggest possibility of impaired LV contractile mechanics during stress in CCS, and 4) cumulative anthracycline dose and chest-directed radiotherapy are consistently identified as factors associated with impaired myocardial deformation.results CONCLUSIONS: Myocardial strain imaging by STE unveils early evidence of myocardial injury in childhood cancer patients and long-term CCS. To support its adoption for clinical use, more data are required for the better understating of myocardial deformation parameters in the risk stratification of childhood cancer patients and prediction of development of cardiomyopathy among CCS.

Current State of Pediatric Cardio-Oncology: A Review

The landscape of pediatric oncology has dramatically changed over the course of the past several decades with five-year survival rates surpassing 80%. Anthracycline therapy has been the cornerstone of many chemotherapy regimens for pediatric patients since its introduction in the 1960s, and recent improved survival has been in large part due to advancements in chemotherapy, refinement of supportive care treatments, and development of novel therapeutics such as small molecule inhibitors, chimeric antigen receptor T-cell therapy, and immune checkpoint inhibitors. Unfortunately, many cancer-targeted therapies can lead to acute and chronic cardiovascular pathologies. The range of cardiotoxicity can vary but includes symptomatic or asymptotic heart failure, arrhythmias, coronary artery disease, valvar disease, pericardial disease, hypertension, and peripheral vascular disease. There is lack of data guiding primary prevention and treatment strategies in the pediatric population, which leads to substantial practice variability. Several important future research directions have been identified, including as they relate to cardiac disease, prevention strategies, management of cardiovascular risk factors, risk prediction, early detection, and the role of genetic susceptibility in development of cardiotoxicity. Continued collaborative research will be key in advancing the field. The ideal model for pediatric cardio-oncology is a proactive partnership between pediatric cardiologists and oncologists in order to better understand, treat, and ideally prevent cardiac disease in pediatric oncology patients.

Exercise and Childhood Cancer-A Historical Review

Simple Summary

Childhood cancer survivors are at risk of developing important adverse effects, but there is growing evidence that physical exercise could help in this regard. The present review summarizes the history of pediatric exercise oncology and the main milestones achieved along the way. Overall, physical exercise appears to be safe and beneficial even during the most aggressive phases of pediatric cancer treatment and can represent an effective coadjuvant therapy for attenuating cancer-related adverse effects.

Abstract

Childhood cancer survivors are at risk of developing important adverse effects, many of which persist for years after the end of treatment. The implementation of interventions aiming at attenuating tumor/treatment-associated adverse effects is therefore a major issue in pediatric oncology, and there is growing evidence that physical exercise could help in this regard. The present review aims to summarize the main milestones achieved in pediatric exercise oncology. For this purpose, we conducted a systematic review of relevant studies written in English in the electronic database PubMed (from inception to 14 August 2021). This review traces the field of pediatric exercise oncology throughout recent history based on three fundamental pillars: (i) exercise during childhood cancer treatment; (ii) exercise during/after hematopoietic stem cell transplantation; and (iii) exercise after childhood cancer treatment. Accumulating evidence––although still preliminary in many cases––supports the safety and potential benefits of regular exercise (with no major contraindications in general) in the childhood cancer continuum, even during the most aggressive phases of treatment. Exercise can indeed represent an effective coadjuvant therapy for attenuating cancer-related adverse effects.

Physical activity and fitness in childhood cancer survivors: a scoping review

BACKGROUND

Estimates indicate that nearly eight percent of the over 500,000 survivors of childhood cancer living in the United States are frail in their fourth and fifth decades of life, a phenotype typically seen in geriatric populations. Participation in regular physical activity to improve physical fitness in healthy and diseased populations reduces risk for frail health by increasing physiologic reserve. However, physical activity may not have the same effects on fitness in childhood cancer survivors as it does among their peers with no cancer history.

AIMS

This scoping review seeks to describe associations between physical activity, physical fitness, chronic disease, and mortality in childhood cancer survivors.

METHODS

Relevant literature was identified through a comprehensive search in the PubMed, Web of Science, CINAHL, and Cochrane databases. A narrative synthesis was performed on observational studies that had physical activity or physical fitness clearly defined and compared with chronic disease outcomes.

RESULTS

A total of 595 studies were screened, and results from 11 studies are presented. Childhood cancer survivors who participate in regular physical activity have improved markers of cardiovascular health, decreased risk of overt cardiovascular disease, and decreased risk of all-cause mortality compared to survivors who are not physically active. Childhood cancer survivors who are physically fit have increased neurocognition, and decreased risk of all-cause mortality compared to survivor's who are not fit. The differential effects of physical activity on fitness and health among childhood cancer survivors when compared to peers is potentially related to treatment exposures that damage cardiovascular tissue and impact regenerative potential.

CONCLUSION

Research is needed to determine the optimal timing, frequency, intensity, and duration of physical activity necessary to optimize fitness in childhood cancer survivors.

Future Perspectives of Cardiovascular Biomarker Utilization in Cancer Survivors: A Scientific Statement From the American Heart Association

Improving cancer survival represents the most significant effect of precision medicine and personalized molecular and immunologic therapeutics. Cardiovascular health becomes henceforth a key determinant for the direction of overall outcomes after cancer. Comprehensive tissue diagnostic studies undoubtedly have been and continue to be at the core of the fight against cancer. Will a systemic approach integrating circulating blood-derived biomarkers, multimodality imaging technologies, strategic panomics, and real-time streams of digitized physiological data overcome the elusive cardiovascular tissue diagnosis in cardio-oncology? How can such a systemic approach be personalized for application in day-to-day clinical work, with diverse patient populations, cancer diagnoses, and therapies? To address such questions, this scientific statement approaches a broad definition of the biomarker concept. It summarizes the current literature on the utilization of a multitude of established cardiovascular biomarkers at the intersection with cancer. It identifies limitations and gaps of knowledge in the application of biomarkers to stratify the cardiovascular risk before cancer treatment, monitor cardiovascular health during cancer therapy, and detect latent cardiovascular damage in cancer survivors. Last, it highlights areas in biomarker discovery, validation, and clinical application for concerted efforts from funding agencies, scientists, and clinicians at the cardio-oncology nexus.

Physical activity levels, exercise preferences, and exercise barriers in Korean children and adolescents after cancer treatment

PURPOSE

The purpose of the current study was to explore physical activity (PA) levels, exercise preferences, and perceived barriers to PA in childhood cancer survivors.

METHODS

This cross-sectional study surveyed 120 childhood cancer survivors aged 8-18 years from the pediatric oncology center in South Korea between March and August 2017. The modified Exercise & Quality of Life questionnaire, Korea Youth Risk Behavior Web-based Survey, and Godin Leisure-Time Questionnaire were used to assess PA levels, preferences, and exercise barriers.

RESULTS

Among 120 participants (72 boys, 48 girls) whose average age at the time of the survey was 14.57 ± 3.00 years and the average age at diagnosis was 8.22 years, the three most common diagnoses were acute leukemia (43.3%), brain tumor (13.3%), and malignant lymphoma (10.8%). Only 16 participants (5%) met the PA recommendations for children (at least 60 min of moderate PA per day). The most preferred sporting activities included soccer, basketball, strengthening exercises, badminton, dance, and taekwondo. They generally had positive attitudes toward exercise, and more than 63% of participants intended to exercise the following month. The five most prevalent perceived barriers to exercise were lack of time, poor health, reluctance to sweat, lack of exercise skills, and no exercise partners.

CONCLUSIONS

While most childhood cancer survivors did not meet the PA recommendation, most of them agreed that exercise was beneficial, and they intended to participate in the exercise. Exercise and PA programs should be tailored to the personal health and preferences of childhood cancer survivors.

Cardiorespiratory fitness and physical performance after childhood hematopoietic stem cell transplantation: a systematic review and meta-analysis

The effects of childhood hematopoietic stem cell transplantation (HSCT) on key organs can impair cardiorespiratory fitness, muscle strength, and physical performance. We aimed to provide an overview of childhood HSCT survivors' status on these parameters compared with healthy controls and discuss current insights into clinical risk factors. We performed a systematic search in six scientific databases, including studies published before April 2019 and performed a meta-analysis on cardiorespiratory fitness. Muscle strength and physical performance status were presented narratively. We included ten studies embodying 517 childhood HSCT survivors (mean 17.8 years at follow-up). The meta-analysis (n = 4 studies) showed that childhood HSCT survivors have lower cardiorespiratory fitness compared with healthy controls (Standard mean difference (SMD) -1.32 [95% CI -1-58 to -1.07]; I² 2%, p < 0.00001). Collectively, the studies indicated that childhood HSCT survivors have lower muscle strength (n = 4 studies) and physical performance (n = 3 studies) compared with healthy controls. Childhood HSCT survivors have impaired cardiorespiratory fitness years after ended treatment. Muscle strength and physical performance seem to be impaired, although these measures are insufficiently investigated. Associations between HSCT-specific clinical risk factors and cardiorespiratory fitness, muscle strength, and physical performance are required.

Cardiac remodeling after anthracycline and radiotherapy exposure in adult survivors of childhood cancer: A report from the St Jude Lifetime Cohort Study

BACKGROUND

Limited data exist regarding left ventricular remodeling patterns observed in adult survivors of childhood cancer after therapy.

METHODS

Among 1190 adult survivors diagnosed with childhood cancer (median age at diagnosis, 9 years [interquartile range (IQR), 3.8-14.4 years]; age at evaluation, 35.6 years [IQR, 29.5-42.8 years]), treatment exposures included anthracyclines (n = 346), chest radiotherapy (n = 174), both (n = 245), or neither (n = 425). Prospective echocardiographic assessment compared survivors with 449 noncancer controls classified according to left ventricle geometric patterns. Associations between left ventricle geometric patterns and decreased exercise tolerance were assessed.

RESULTS

Overall, 28.2% of survivors (95% confidence interval [CI], 25.6%-30.8%) exhibited concentric remodeling, 2.4% (95% CI, 1.6%-3.5%) exhibited eccentric hypertrophy, and 1.1% (95% CI, 0.6%-1.9%) exhibited concentric hypertrophy. A greater proportion of survivors who received only chest radiotherapy (41%) had concentric remodeling compared with those who received only anthracyclines (24%), both (27%), or neither (27%; all P < .001), and all were greater than the proportions in noncancer controls (18%; all P < .05). Concentric remodeling was associated with radiation exposure, but not with anthracycline exposure, in multivariable models. Survivors who had concentric remodeling were more likely to have a maximal oxygen uptake peak <85% compared with those who had normal geometry (81.0% vs 66.3%; odds ratio, 1.75; 95% CI, 1.15-2.68).

CONCLUSIONS

Chest radiation therapy, but not anthracycline therapy, increased the risk for concentric remodeling in survivors of childhood cancer. The presence of concentric remodeling was associated with increased exercise intolerance.

Vo2peak in Adult Survivors of Hodgkin Lymphoma: Rate of Decline, Sex Differences, and Cardiovascular Events

Background

Adult survivors of Hodgkin lymphoma (HL) are at increased risk of cardiovascular (CV) events secondary to mediastinal radiation therapy (RT).

Objectives

In this group of patients, we assessed the association between cardiopulmonary exercise testing (CPET), as determined by percent-predicted peak Vo₂ (ppVo₂peak), and clinical outcomes, as well as the rate of ppVo₂peak decline and sex differences.

Methods

All survivors of HL who were >10 years post chest RT and who underwent ≥1 CPET were enrolled from a single center. Traditional CV and treatment risk factors, along with CV events, were ascertained.

Results

A total of 64 patients (67% female; median age 51 years [range 26 to 70 years]) with a median follow-up time after RT of 23 years (range 11 to 41 years), and 141 CPET studies, were included. Median initial ppVo₂peak was 91% (range 58% to 138%). ppVo₂peak in survivors declined by 7.5 percentage points every 10-year period after RT, as compared with age- and sex-based norms (P = 0.001), even after adjusting for hypertension and history of anthracycline. Both male and female patients had a similar rate of ppVo₂peak decline. However, women had a lower ppVo₂peak at all times, and they developed abnormal ppVo₂peak (≤85%) on average earlier than men (24.1 years vs 47.0 years after RT). Patients with abnormal ppVo₂peak vs normal ppVo₂peak (>85%), had an increased risk of CV events (59% vs 16%). Abnormal ppVo₂peak was independently associated with the risk of CV events (adjusted HR: 6.37; 95% CI: 2.06-19.80; P = 0.001).

Conclusions

Percent-predicted Vo₂peak in long-term survivors of HL who were treated with chest RT progressively declined as compared with population- and sex-based norms. Importantly, women developed abnormal ppVo₂peak more than 2 decades earlier than male survivors. Abnormal ppVo₂peak was associated with an increased risk of CV events in this group of patients.

Skeletal Muscle and Childhood Cancer: Where are we now and where we go from here

Skeletal muscle (muscle) is essential for physical health and for metabolic integrity, with sarcopenia (progressive muscle mass loss and weakness), a pre-curser of aging and chronic disease. Loss of lean mass and muscle quality (force generation per unit of muscle) in the general population are associated with fatigue, weakness, and slowed walking speed, eventually interfering with the ability to maintain physical independence, and impacting participation in social roles and quality of life. Muscle mass and strength impairments are also documented during childhood cancer treatment, which often persist into adult survivorship, and contribute to an aging phenotype in this vulnerable population. Although several treatment exposures appear to confer increased risk for loss of mass and strength that persists after therapy, the pathophysiology responsible for poor muscle quantity and quality is not well understood in the childhood cancer survivor population. This is partly due to limited access to both pediatric and adult survivor muscle tissue samples, and to difficulties surrounding non-invasive investigative approaches for muscle assessment. Because muscle accounts for just under half of the body's mass, and is essential for movement, metabolism and metabolic health, understanding mechanisms of injury responsible for both initial and persistent dysfunction is important, and will provide a foundation for intervention. The purpose of this review is to provide an overview of the available evidence describing associations between childhood cancer, its treatment, and muscle outcomes, identifying gaps in current knowledge.

Cardiorespiratory fitness and all-cause mortality in adults diagnosed with cancer systematic review and meta-analysis

INTRODUCTION

The inverse association between cardiorespiratory fitness and all-cause mortality in apparently healthy populations has been previously reported; however, the existence of this association among adults diagnosed with cancer is unclear.

AIM

To determine the association between cardiorespiratory fitness and all-cause mortality in adults diagnosed with cancer.

METHODS

Medline, Embase, and SPORTDiscus databases were searched. Eligible prospective cohort studies that examined the association of cardiorespiratory fitness with all-cause mortality in adults diagnosed with cancer were included. Hazard ratios (HRs) with associated 95% confidence intervals (CIs) were extracted from studies for all-cause mortality and pooled HRs were calculated using the random-effects inverse-variance model with the Hartung-Knapp-Sidik-Jonkman adjustment.

RESULTS

Data from 13 studies with 6,486 adults were included. Compared with lower levels of cardiorespiratory fitness, high levels were associated with a reduced risk of all-cause mortality among adults diagnosed with any cancer (HR = 0.52; 95% CI, 0.35-0.77), lung cancer (HR = 0.62; 95% CI, 0.46-0.83), and among those with cardiorespiratory fitness measurement via indirect calorimetry (HR = 0.47; 95% CI, 0.27-0.80). Pooled HRs for the reduction in all-cause mortality risk per 1-MET increase were also statistically significant (HR = 0.82; 95% CI, 0.69-0.99). Neither age at baseline nor the length of follow-up had a significant influence on the HR estimates for all-cause mortality risk.

CONCLUSION

Cardiorespiratory fitness may confer an independent protective benefit against all-cause mortality in adults diagnosed with cancer. The use of cardiorespiratory fitness as a prognostic parameter might help determine risk for future adverse clinical events and optimize therapeutic management strategies to reduce long-term treatment-related effects in adults diagnosed with cancer.

Breast Radiotherapy-Related Cardiotoxicity. When, How, Why. Risk Prevention and Control Strategies

In recent decades, improvements in breast cancer management have increased overall patient survival; however, many cancer therapies have been linked to an important risk of cardiovascular adverse events. Cardio-oncology has been proposed as an emerging specialty to coordinate preventive strategies that improve the cardiovascular health of oncologic patients. It employs the most suitable personalized multidisciplinary management approach for each patient to optimize their cardiovascular health and improve their survival and quality of life. Radiotherapy is an essential part of the therapeutic regimen in breast cancer patients but can also increase the risk of cardiovascular disease. Therefore, minimizing the negative impact of radiation therapy is an important challenge for radiotherapy oncologists and cardiologists specializing in this field. The aim of the present review is to update our knowledge about radiation-induced cardiotoxicity in breast cancer patients by undertaking a critical review of the relevant literature to determine risk prevention and control strategies currently available.

Echocardiographic myocardial strain analysis describes subclinical cardiac dysfunction after craniospinal irradiation in pediatric and young adult patients with central nervous system tumors

Background

Craniospinal irradiation (CSI) is part of the treatment of central nervous system (CNS) tumors and is associated with cardiovascular disease in adults. Global myocardial strain analysis including longitudinal peak systolic strain (GLS), circumferential peak systolic strain (GCS), and radial peak systolic strain (GRS) can reveal subclinical cardiac dysfunction.

Methods

Retrospective, single-center study in patients managed with CSI vs. age-matched controls. Clinical data and echocardiography, including myocardial strain analysis, were collected at early (< 12 months) and late (≥ 12 months) time points after completion of CSI.

Results

Echocardiograms were available at 20 early and 34 late time points. Patients at the late time point were older (21.7 ± 10.4 vs. 13.3 ± 9.6 years) and further out from CSI (13.1 ± 8.8 vs. 0.2 ± 0.3 years). Standard echocardiographic parameters were normal for both groups. For early, CSI vs. control: GLS was − 16.8 ± 3.6% vs. -21.3 ± 4.0% (p = 0.0002), GCS was − 22.5 ± 5.2% vs. -21.3 ± 3.4% (p = 0.28), and GRS was 21.8 ± 11.0% vs. 26.9 ± 7.7% (p = 0.07). For late, CSI vs. control: GLS was − 16.2 ± 5.4% vs. -21.6 ± 3.7% (p < 0.0001), GCS was − 20.9 ± 6.8% vs. -21.9 ± 3.5% (p = 0.42), and GRS was 22.5 ± 10.0% vs. 27.3 ± 8.3% (p = 0.03). Radiation type (proton vs. photon), and radiation dose (< 30 Gy vs. ≥ 30 Gy) did not impact any parameter, although numbers were small.

Conclusions

Subclinical cardiac systolic dysfunction by GLS is present both early and late after CSI. These results argue for future studies to determine baseline cardiovascular status and the need for early initiation of longitudinal follow-up post CSI.

A randomized controlled trial of a structured exercise intervention after the completion of acute cancer treatment in adolescents and young adults

BACKGROUND

Cancer treatments are frequently associated with impaired physical fitness, quality of life (QOL), and fatigue, often persisting into survivorship.  Studies in older adults with cancer have demonstrated benefits from exercise; however, this has not been rigorously investigated in adolescents and young adults (AYA). The aim of this study was to determine whether a structured 10-week exercise intervention was associated with improved cardiorespiratory fitness (VO_2peak ), fatigue, and QOL in AYA who have recently completed cancer treatment.

METHOD

Forty-three AYA (median age 21 ± 6 years) were randomly assigned to an exercise group (n = 22) or a control group (n = 21). The exercise group received a structured 10-week exercise program comprising progressive aerobic and resistance exercise; the control arm received routine care. VO_2peak was measured at baseline, 10 weeks, and six months. Fatigue and QOL were assessed by the FACIT fatigue scale and the PEDS QL, respectively.

RESULTS

Mean VO_2peak at baseline was 26.5 ± 7.2 mL.kg^-1 .min^-1 , which is substantially lower than population norms. The exercise group demonstrated significant improvement in VO_2peak at 10 weeks compared with controls (33.8 ± 8.1 vs 29.6 ± 7.6 mL.kg^-1 .min^-1 , P = 0.0002), but by six months, the difference was no longer significant (32.9 ± 7.0 vs 30.9 ± 11.0 mL.kg^-1 .min^-1 , P = 0.21). There were no significant differences in fatigue or total QOL scores between groups.

CONCLUSION

Cancer treatment is associated with reduced VO_2peak in AYA. Improvement in VO_2peak was accelerated by a 10-week exercise program; however, no significant benefit was observed in QOL or fatigue. The plateau in VO_2peak at six months suggests that a maintenance exercise program may be beneficial.

Strain Imaging in Cardio-Oncology

Echocardiographic imaging is crucial for patient management during cardiotoxic cancer therapy. Left ventricular ejection fraction is the most commonly used parameter for identifying left ventricular dysfunction. However, it lacks sensitivity to detect subclinical changes in cardiac function due to cardiotoxic treatment. Global longitudinal strain (GLS) is the best studied strain parameter with established diagnostic and prognostic value. Multiple studies have demonstrated changes in GLS as an early marker of cardiotoxicity. This document serves as a primer to help clinicians in the acquisition and interpretation of strain in cardio-oncology. Cases with embedded videos illustrate a step-by-step approach to obtaining GLS measurements and common pitfalls to avoid. The document includes a concise summary of the indications of GLS in cardio-oncology and its role in guiding oncological therapy. Practical approaches on how to implement strain in the echo laboratory with guidance on training and quality assurance are also discussed.