Identifying Cardiovascular Risk in Survivors of Childhood Leukaemia Treated with Haematopoietic Stem Cell Transplantation and Total Body Irradiation

Clinical response to lifestyle counseling for dyslipidemia and elevated blood pressure in childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) have increased risk of premature cardiovascular disease. Whether they respond similarly to lifestyle changes for elevated blood pressure (BP), body mass index (BMI), and dyslipidemia to those without history of childhood cancer is unknown.

PROCEDURE

This retrospective cohort study included CCS and 3:1 age- and sex-matched controls treated at Boston Children's Hospital Preventive Cardiology (2010-2019) using lifestyle management based on National Heart, Lung, and Blood Institute (NHLBI) guidelines. Change in BMI, BP, and lipids were analyzed.

RESULTS

We included 52 CCS and 162 controls with a median age of approximately 16 years. More CCS (84.3%) had elevated baseline fasting triglycerides (TG) than controls (49.4%) (p < .001). More CCS (62.5%) also had abnormal baseline high-density lipoprotein cholesterol (HDL-C) compared to controls (35.2%) (p = .001). Baseline BMI, BP, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) were similar between groups. Over 15 weeks [IQR: 10.5-26], CCS had greater decrease in TG than controls (72.5 vs. 17 mg/dl decrease, p = .095). BP improved in 5% of CCS versus 38% of controls (p = .008). For both, BMI, TC, LDL-C, and HDL-C remained stable. CCS with stem cell transplantation (SCT) had a TC increase of 5% (6 mg/dl) compared to a decrease of 9% (19 mg/dl) among CCS without SCT (p = .02).

CONCLUSIONS

CCS demonstrated similar improvement in lipids, but impaired BP lowering in response to lifestyle management compared to controls. Further prospective studies are needed to determine if earlier pharmaceutical treatment is warranted in this higher risk population and for the long-term risk reductions of these approaches.

Total Body Irradiation in Haematopoietic Stem Cell Transplantation for Paediatric Acute Lymphoblastic Leukaemia: Review of the Literature and Future Directions

Total body irradiation (TBI) has been a pivotal component of the conditioning regimen for allogeneic myeloablative haematopoietic stem cell transplantation (HSCT) in very-high-risk acute lymphoblastic leukaemia (ALL) for decades, especially in children and young adults. The myeloablative conditioning regimen has two aims: (1) to eradicate leukaemic cells, and (2) to prevent rejection of the graft through suppression of the recipient's immune system. Radiotherapy has the advantage of achieving an adequate dose effect in sanctuary sites and in areas with poor blood supply. However, radiotherapy is subject to radiobiological trade-offs between ALL cell destruction, immune and haematopoietic stem cell survival, and various adverse effects in normal tissue. To diminish toxicity, a shift from single-fraction to fractionated TBI has taken place. However, HSCT and TBI are still associated with multiple late sequelae, leaving room for improvement. This review discusses the past developments of TBI and considerations for dose, fractionation and dose-rate, as well as issues regarding TBI setup performance, limitations and possibilities for improvement. TBI is typically delivered using conventional irradiation techniques and centres have locally developed heterogeneous treatment methods and ways to achieve reduced doses in several organs. There are, however, limitations in options to shield organs at risk without compromising the anti-leukaemic and immunosuppressive effects of conventional TBI. Technological improvements in radiotherapy planning and delivery with highly conformal TBI or total marrow irradiation (TMI), and total marrow and lymphoid irradiation (TMLI) have opened the way to investigate the potential reduction of radiotherapy-related toxicities without jeopardising efficacy. The demonstration of the superiority of TBI compared with chemotherapy-only conditioning regimens for event-free and overall survival in the randomised For Omitting Radiation Under Majority age (FORUM) trial in children with high-risk ALL makes exploration of the optimal use of TBI delivery mandatory. Standardisation and comprehensive reporting of conventional TBI techniques as well as cooperation between radiotherapy centres may help to increase the ratio between treatment outcomes and toxicity, and future studies must determine potential added benefit of innovative conformal techniques to ultimately improve quality of life for paediatric ALL patients receiving TBI-conditioned HSCT.

Comparison of blood pressure values and expression of genes associated with hypertension in children before and after hematopoietic cell transplantation

Hypertension is a well-known late effect of hematopoietic cell transplantation (HCT), but no markers predicting its development are known. Our aim was to assess short-term blood pressure (BP) values and expressions of hypertension-associated genes as possible markers of hypertension in children treated with HCT. We measured systolic blood pressure (SBP) and diastolic blood pressure (DBP), using both office procedure and ambulatory BP monitoring (ABPM) in children before HCT and after a median of 6 months after HCT. We compared the results with two control groups, one of healthy children and another of children with simple obesity. We also performed microarray analysis of hypertension-associated genes in patients treated with HCT and children with obesity. We found no significant differences in SBP and DBP in patients before and after HCT. We found significant differences in expressions of certain genes in patients treated with HCT compared with children with obesity. We concluded that BP values in short-term follow-up after HCT do not seem to be useful predictors of hypertension as a late effect of HCT. However, over expressions of certain hypertension-associated genes might be used as markers of hypertension as a late effect of HCT if this is confirmed in larger long-term studies.

Metreleptin worked in a diabetic woman with a history of hematopoietic stem cell transplantation (HSCT) during infancy: further support for the concept of 'HSCT-associated lipodystrophy'

A 17-year-old woman with a history of childhood leukemia and hematopoietic stem cell transplantation (HSCT), preceded by total body irradiation, developed diabetes, dyslipidemia, fatty liver, and marked insulin resistance. Based on Dunnigan phenotype, HSCT-associated lipodystrophy was suspected. Because of rapid deterioration of diabetes control, metreleptin was introduced at 23 years of age upon receipt of her caregiver's documented consent. This trial was initially planned as a prospective 18 month-long study, with regular assessments of the patient's physical activity, food intake, and body composition analysis. However, because an abrupt and transient attenuation of the metreleptin effect occurred 16 months after the treatment initiation, the entire course of 28 months is reported here. Over the period, her HbA1c decreased from 10.9% to 6.7% despite no significant increase of physical activity and with a stable food intake. Decreased levels of triglyceride and non-HDL cholesterol were found. Her liver function improved, indicating the amelioration of fatty liver. In addition, a 25% reduction in the subcutaneous fat area at umbilical level was found, accompanied by a decrease in fat percentage of both total-body and trunk. The formation of neutralizing antibodies to metreleptin may be responsible for the transient loss of efficacy, considering a sudden elevation in her serum leptin level. In conclusion, metreleptin is useful for the management of HSCT-associated lipodystrophy, supporting the concept that adipose tissue dysfunction is responsible for diverse post-HSCT metabolic aberrations.

A Review of Acute and Long-Term Neurological Complications Following Haematopoietic Stem Cell Transplant for Paediatric Acute Lymphoblastic Leukaemia

Despite advances in haematopoietic stem cell transplant (HSCT) techniques, the risk of serious side effects and complications still exists. Neurological complications, both acute and long term, are common following HSCT and contribute to significant morbidity and mortality. The aetiology of neurotoxicity includes infections and a wide variety of non-infectious causes such as drug toxicities, metabolic abnormalities, irradiation, vascular and immunologic events and the leukaemia itself. The majority of the literature on this subject is focussed on adults. The impact of the combination of neurotoxic drugs given before and during HSCT, radiotherapy and neurological complications on the developing and vulnerable paediatric and adolescent brain remains unclear. Moreover, the age-related sensitivity of the nervous system to toxic insults is still being investigated. In this article, we review current evidence regarding neurotoxicity following HSCT for acute lymphoblastic leukaemia in childhood. We focus on acute and long-term impacts. Understanding the aetiology and long-term sequelae of neurological complications in children is particularly important in the current era of immunotherapy for acute lymphoblastic leukaemia (such as chimeric antigen receptor T cells and bi-specific T-cell engager antibodies), which have well-known and common neurological side effects and may represent a future treatment modality for at least a fraction of HSCT-recipients.

Body composition after allogeneic haematopoietic cell transplantation/total body irradiation in children and young people: a restricted systematic review

PURPOSE

To collate evidence of changes in body composition following treatment of leukaemia in children, teenagers and young adults (CTYA, 0-24 years) with allogeneic haematopoietic stem cell transplant and total body irradiation (HSCT+TBI).

METHODS

Papers were identified by searching Medline and Google Scholar, reference lists/citations and contacting key authors, with no date or language restrictions. Inclusion criteria were as follows: leukaemia, HSCT+TBI, aged ≤ 24 years at HSCT and changes in body composition (total fat, central adiposity, adipose tissue function, muscle mass, muscle function). Quality was assessed using a brief Newcastle-Ottawa scale.

RESULTS

Of 900 papers, 20 were included: seven controlled, five uncontrolled studies and eight case reports. Study quality appeared good. There was little evidence of differences in total fat/weight for HSCT + TBI groups (compared to healthy controls/population norms/short stature controls). There was some evidence of significantly higher central adiposity and differences in adipose tissue function (compared to leukaemic/non-leukaemic controls). Muscle mass was significantly lower (compared to healthy/obese controls). Muscle function results were inconclusive but suggested impairment. Case reports confirmed a lipodystrophic phenotype.

CONCLUSIONS

Early remodelling of adipose tissue and loss of skeletal muscle are evident following HSCT + TBI for CTYA leukaemia, with extreme phenotype of overt lipodystrophy. There is some evidence for reduced muscle effectiveness.

IMPLICATIONS FOR CANCER SURVIVORS

Body composition changes in patients after HSCT + TBI are apparent by early adult life and link with the risk of excess cardiometabolic morbidity seen in adult survivors. Interventions to improve muscle and/or adipose function, perhaps utilizing nutritional manipulation and/or targeted activity, should be investigated.

Cardiac autonomic dysfunction in survivors of childhood acute lymphoblastic leukemia: The St. Jude Lifetime Cohort Study

BACKGROUND

Cardiac autonomic dysfunction (CAD) is possible following treatment for childhood cancer. The aims of our analyses were to compare the prevalence of CAD between adult survivors of childhood acute lymphoblastic leukemia and controls, compare exercise response among survivors with and without CAD, and identify treatment-related risk factors for CAD.

PROCEDURE

Participants were treated for childhood acute lymphoblastic leukemia at St. Jude Children's Research Hospital between 1980 and 2003 (N = 338). A comparison group matched for race/ethnicity, age, and sex was also recruited (N = 325). Resting heart rate (HR) was assessed via electrocardiogram, and heart rate recovery (HRR) and exercise capacity were evaluated with submaximal cardiopulmonary exercise testing.

RESULTS

CAD was present in 33.7% of survivors and 27.6% of controls (P = 0.09). Although mean resting HR did not differ between survivors and controls (74 ± 12 vs 72 ± 12 beats per minute (bpm), P = 0.07), survivors had lower mean HRR than controls (22 ± 9 vs 25 ± 10 bpm; P < 0.001). Survivors with CAD had lower peak exercise tolerance (25.7 ± 6.5 vs 21.2 ± 4.9 mL/kg/min, P < 0.001) than those without. Survivors treated with cyclophosphamide in combination with vincristine ≥38 mg/m² and/or glucocorticoids ≥10 000 mg/m² were 1.56 (95% CI 1.09-2.24) times more likely to have CAD than those without this treatment. Obese survivors were 1.78 (95% CI: 1.31-2.40) times more likely to have CAD than nonobese survivors (P < 0.001).

CONCLUSION

CAD was present in over one third of survivors and was associated with lower exercise capacity. Obese survivors and those exposed to cyclophosphamide with high doses of vincristine and/or corticosteroids were at greatest risk.

Type 2 Diabetes Mellitus, the Metabolic Syndrome, and Its Components in Adult Survivors of Acute Lymphoblastic Leukemia and Hematopoietic Stem Cell Transplantations

PURPOSE OF REVIEW

A growing number of pediatric acute lymphoblastic leukemia (ALL) and hematopoietic stem cell transplantation (HSCT) survivors reach adulthood and face long-term health-related problems. We review risk factors and the prevalence of the metabolic syndrome (MetS), a cluster of obesity-related comorbidities, including abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, impaired glucose metabolism, and type 2 diabetes in ALL and HSCT survivors.

RECENT FINDINGS

Components of the MetS are already detected during the first year of ALL maintenance therapy and significantly worsen over time. The prevalence of MetS increases at a faster rate in this setting than in the general population. Factors found to be of the greatest potential risk to the development of the MetS are central obesity, increased BMI, irradiation therapy, older age, poor diet, and low level of physical activity. The early onset of MetS and its components among ALL and HSCT survivors calls for early and continuous screening to identify those at risk and to implement preventive measures.