Pulmonary Dysfunction after Treatment for Childhood Cancer. Comparing Multiple-Breath Washout with Spirometry

Recommendations for surveillance of pulmonary dysfunction among childhood, adolescent, and young adult cancer survivors: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Childhood, adolescent, and young adult (CAYA) cancer survivors are at risk of pulmonary dysfunction. Current follow-up care guidelines are discordant. Therefore, the International Late Effects of Childhood Cancer Guideline Harmonization Group established and convened a panel of 33 experts to develop evidence-based surveillance guidelines. We critically reviewed available evidence regarding risk factors for pulmonary dysfunction, types of pulmonary function testing, and timings of surveillance, then we formulated our recommendations. We recommend that CAYA cancer survivors and healthcare providers are aware of reduced pulmonary function risks and pay vigilant attention to potential symptoms of pulmonary dysfunction, especially among survivors treated with allogeneic haematopoietic stem cell transplantation, thoracic radiotherapy, and thoracic surgery. Based on existing limited evidence and current lack of interventions, our panel recommends pulmonary function testing only for symptomatic survivors. Since scarce existing evidence informs our recommendation, we highlight the need for prospective collaborative studies to address pulmonary function knowledge gaps among CAYA cancer survivors.

Longitudinal assessment of lung function in Swiss childhood cancer survivors-A multicenter cohort study

OBJECTIVE

Childhood cancer survivors are at risk for pulmonary morbidity due to exposure to lung-toxic treatments, including specific chemotherapeutics, radiotherapy, and surgery. Longitudinal data on lung function and its change over time are scarce. We investigated lung function trajectories in survivors over time and the association with lung-toxic treatments.

METHODS

This retrospective, multicenter cohort study included Swiss survivors diagnosed between 1990 and 2013 and exposed to lung-toxic chemotherapeutics or thoracic radiotherapy. Pulmonary function tests (PFTs), including forced expiration volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, total lung capacity,  and diffusion capacity of the lung for carbon monoxide, were obtained from hospital charts. We calculated z-scores and percentage predicted, described lung function over time, and determined risk factors for change in FEV1 and FVC using multivariable linear regression.

RESULTS

We included 790 PFTs from 183 survivors, with a median age of 12 years at diagnosis and 5.5 years of follow-up. Most common diagnosis was lymphoma (55%). Half (49%) of survivors had at least one abnormal pulmonary function parameter, mainly restrictive (22%). Trajectories of FEV1 and FVC started at z-scores of -1.5 at diagnosis and remained low throughout follow-up. Survivors treated with thoracic surgery started particularly low, with an FEV1 of -1.08 z-scores (-2.02 to -0.15) and an FVC of -1.42 z-scores (-2.27 to -0.57) compared to those without surgery.

CONCLUSION

Reduced pulmonary function was frequent but mainly of mild to moderate severity. Nevertheless, more research and long-term surveillance of this vulnerable population is needed.

Multiple breath washout and oscillometry after allogenic HSCT: a scoping review

Pulmonary chronic graft-versus-host disease (cGVHD) is a substantial cause of pulmonary morbidity and mortality post-haematopoietic stem cell transplantation (HSCT). Current spirometry-based monitoring strategies have significant limitations. Understanding the utility of novel peripheral airway function tests - multiple breath washout (MBW) and oscillometry - is critical in efforts to improve detection, facilitate earlier intervention and improve outcomes. In this scoping review, we identified 17 studies investigating MBW or oscillometry, or both, after allogenic HSCT. Despite small study numbers limiting the ability to draw firm conclusions, several themes were evident. Detectable peripheral airway abnormality in MBW occurred in a substantial proportion prior to HSCT. MBW indices post-HSCT were more frequently abnormal than spirometry when reporting group data and among those with extrapulmonary cGVHD and pulmonary cGVHD. Changes in MBW indices over time may be more indicative of pulmonary complications than absolute values at any given time point. Oscillometry indices were often normal at baseline, but more frequently abnormal in those who developed pulmonary cGVHD. Pooling currently available individual participant data across these studies may improve our ability to formally compare their respective sensitivity and specificity at specific time points and assess the trajectory of MBW and oscillometry indices over time.

Multiple Breath Washout for Early Assessment of Pulmonary Complications in Patients With Primary Antibody Deficiencies: An Observational Study in Pediatric Age

BACKGROUND

In primary antibody deficiencies (PADs), pulmonary complications are the main cause of morbidity, despite immunoglobulin substitutive therapy, antibiotic treatment of exacerbations, and respiratory physiotherapy. Current Italian recommendations for surveillance of PADs respiratory complications include an annual assessment of spirometry and execution of chest high-resolution computed tomography (HRCT) every 4 years.

OBJECTIVE

This study aimed to evaluate the effectiveness of the lung clearance index (LCI) as an early marker of lung damage in patients with PADs. LCI is measured by multiple breath washout (MBW), a non-invasive and highly specific test widely used in patients with cystic fibrosis (CF).

METHODS

Pediatric patients with PADs (n = 17, 10 male, 7 female, and age range 5-15 years) underwent baseline assessment of lung involvement with chest HRCT, spirometry, and multiple breath nitrogen washout. Among them, 13 patients were followed up to repeat HRCT after 4 years, while performing pulmonary function tests annually. Their baseline and follow-up LCI and forced expiratory volume at 1 s (FEV1) values were compared, taking HRCT as the gold standard, using logistic regression analysis.

RESULTS

Lung clearance index [odds ratio (OR) 2.3 (confidence interval (CI) 0.1-52) at baseline, OR 3.9 (CI 0.2-191) at follow-up] has a stronger discriminating power between altered and normal HRCT rather than FEV1 [OR 0.6 (CI 0.2-2) at baseline, OR 1.6 (CI 0.1-13.6) at follow-up].

CONCLUSION

Within the context of a limited sample size, LCI seems to be more predictive of HRCT alterations than FEV1 and more sensitive than HRCT in detecting non-uniform ventilation in the absence of bronchiectasis. A study of a larger cohort of pediatric patients followed longitudinally in adulthood is needed to challenge these findings.