Effectiveness of long-term routine pulmonary function surveillance following pediatric hematopoietic stem cell transplantation

Does allogeneic stem cell transplantation in survivors of pediatric leukemia impact regular physical activity, pulmonary function, and exercise capacity?

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has improved survival in high-risk childhood leukemia but is associated with long-term sequelae such as impaired pulmonary function and reduced exercise capacity impacting quality of life.

METHODS

A convenience sample of 17 patients after allo-HSCT (HSCT-12 male, age 15.7±6.7 years, time after HSCT 5.3±2.8 years) underwent pulmonary function testing, echocardiography, and an incremental exercise test on a bike. Physical activity and health-related quality of life were assessed by questionnaires (7-day physical activity recall, PEDS-QL). Seventeen healthy age- and gender-matched controls served as control group (CG) for results of pulmonary function and exercise testing.

RESULTS

HSCT showed reduced pulmonary function (HSCT vs. CG: FEV1 90.5±14.0 vs. 108.0±8.7%pred; FVC 88.4±19.3 vs. 107.6±6.9%pred, DLCO 75.3±23.6 vs. 104.9±12.8%pred) and exercise capacity (VO₂peak 89±30.8%pred, CG 98±17.5%pred; Wmax 84±21.7%pred, CG 115±22.8%pred), but no relevant cardiac dysfunction and a good quality of life (PEDS-QL mean overall score 83.3±10.7). Differences in peak oxygen uptake between groups were mostly explained by 5 adolescent patients who underwent total body irradiation for conditioning. They showed significantly reduced diffusion capacity and reduced peak oxygen uptake. Patients reported a mean time of inactivity of 777±159min/day, moderate activity of 110±107 min/day, hard activity of 35±36 min/day, and very hard activity of 23±22 min/day. A higher amount of inactivity was associated with a lower peak oxygen uptake (correlation coefficient tau -0.48, p=0.023).

CONCLUSIONS

This pilot study shows that although patients after allo-HSCT reported a good quality of life, regular physical activity and exercise capacity are reduced in survivors of stem cell transplantation, especially in adolescents who are treated with total body irradiation for conditioning. Factors hindering regular physical activity need to be identified and exercise counseling should be part of follow-up visits in these patients.

Lung evaluation in 10 year survivors of pediatric allogeneic hematopoietic stem cell transplantation

There is little data on the long-term respiratory development of children after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We describe the respiratory assessment 10 years after allo-HSCT of 35 children transplanted between 2000 and 2004. During this period, 90 children were transplanted at our center. Twenty-five children died, thirty were lost to follow-up, and thirty-five came to have a pulmonary investigation. The thirty-five participants answered a questionnaire asking if they had pulmonary symptoms, and pulmonary function tests (PFTs) were performed. The median age of these children 10 years after the transplant was 16 years old. Just over a third of them had pulmonary symptoms. Among them, 5/13 (38%) had bronchiolitis obliterans syndrome (BOS). The majority of children (62.8%) did not have respiratory symptoms. PFTs were abnormal in one-third of asymptomatic children, revealing restrictive lung disease that was always mild to moderate (p = 0.02).Conclusion: In the long term, research at the time of the medical examination for the presence of chronic cough, shortness of breath on exertion, or wheezing helps to guide the clinician as to the need for further lung exploration. Similarly, informing patients and their families about these symptoms, which can be underestimated, should allow for more specific management.What is Known:• Pulmonary complications are a major cause of hematopoietic stem cell transplantation (HSCT) morbidity and mortality.• A long time after allogeneic HSCT, pulmonary function tests abnormalities may occur in children, but it is not always related to symptoms.What is New:• The occurrence of respiratory symptoms: cough, dyspnea on exertion, chronic bronchitis, and wheezing should be systematically investigated in the follow-up of allografted patients, even at a distance.• The presence of respiratory symptoms should lead to a respiratory functional investigation to detect the presence of an obstructive syndrome.

Xenon-129 MRI detects ventilation deficits in paediatric stem cell transplant patients unable to perform spirometry

BACKGROUND

Early detection of pulmonary morbidity following haematopoietic stem cell transplantation (HSCT) remains an important challenge for intervention, primarily due to the insensitivity of spirometry to early change, and in paediatrics, patient compliance provides additional challenges. Regional lung ventilation abnormalities in paediatric HSCT patients were quantified using hyperpolarised xenon-129 (129Xe) magnetic resonance imaging (MRI) and compared to spirometry.

METHODS

Medically stable, paediatric allogeneic HSCT patients (n=23, ages 6-16 years) underwent an outpatient MRI scan where regional ventilation was quantified with a breath-hold of hyperpolarised 129Xe gas. Ventilation deficits, regions of the lung that ventilate poorly due to obstruction, were quantified as a ventilation defect percentage (VDP) and compared to forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity (FVC) ratio, and forced expiratory flow at 25-75% of FVC (FEF25-75%) from spirometry using linear regression.

RESULTS

The mean±sd 129Xe VDP was 10.5±9.4% (range 2.6-41.4%). 129Xe VDP correlated with FEV1, FEV1/FVC ratio and FEF25-75% (p≤0.02 for all comparisons). Ventilation deficits were detected in patients with normal spirometry (i.e. FEV1 >80%), supporting the sensitivity of 129Xe MRI to early obstruction reported in other pulmonary conditions. Seven (30%) patients could not perform spirometry, yet ventilation deficits were observed in five of these patients, detecting abnormalities that otherwise may have gone undetected and untreated until advanced.

CONCLUSION

Lung ventilation deficits were detected using hyperpolarised 129Xe gas MRI in asymptomatic paediatric HSCT patients and in a subgroup who were unable to perform reliable spirometry. 129Xe MRI provides a reliable imaging-based assessment of pulmonary involvement in this potentially difficult to diagnose paediatric population.

Monitoring pulmonary health in Swiss childhood cancer survivors

BACKGROUND

Childhood cancer survivors are at increased risk for pulmonary morbidity and mortality. International guidelines recommend pulmonary function tests (PFT) during follow-up care. This nationwide study assessed how many children received PFT within 5 years after pulmotoxic treatment in Switzerland, types of tests, and predictors for testing.

METHODS

We included all children from the Swiss Childhood Cancer Registry who were diagnosed with cancer from 1990 to 2013 at age 0-16 years, survived for ≥2 years from diagnosis, and had pulmotoxic chemotherapy with bleomycin, busulfan, nitrosoureas, and/or chest radiotherapy. We searched medical records in all Swiss pediatric oncology clinics for PFT (spirometry, plethysmography, diffusion capacity of carbon monoxide [DLCO]) and treatment details.

RESULTS

We found medical records for 372 children, of whom 147 had pulmotoxic chemotherapy and 323 chest radiotherapy. Only 185 had plethysmography and/or spirometry (50%), 122 had DLCO (33%). Testing varied by cancer center from 3% to 79% (P = 0.001). Central nervous system tumor survivors and those not treated according to study protocols had less plethysmography and/or spirometry (odds ratio (OR) 0.3 and 0.3), lymphoma survivors and those who were symptomatic had more PFT (plethysmography and/or spirometry: OR 5.9 and 8.7; DLCO: OR 3.4 and 2.3). Cumulative incidence (CuI) of PFT was 52% in the first 5 years after pulmotoxic treatment; most of the tests were done in the first 2 years after treatment (CuI 44%).

CONCLUSION

Only half of the survivors exposed to pulmotoxic treatment have been followed up with PFT in Switzerland. We need to optimize, update, and implement monitoring guidelines.