Analysis of Risk Factors for Abnormal Pulmonary Function in Pediatric Cancer Survivors

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.

A longitudinal analysis of early lung function trajectory in survivors of childhood Hodgkin lymphoma

BACKGROUND

Childhood Hodgkin lymphoma survivors suffer from long-term effects decades after treatment completion with a prevalence of pulmonary dysfunction of up to 65.2%.

AIMS

This study explored the early trajectory of pulmonary function in pediatric cancer patients with Hodgkin lymphoma who received pulmonary toxic therapy.

METHODS AND RESULTS

In this single-center, 20-year retrospective cohort study, we included patients who were <18 years old at diagnosis of Hodgkin lymphoma between January 1994 and December 2014, and received bleomycin or thoracic radiation. We measured pulmonary function and reported on percent predicted values for forced expiratory volume in 1 s, total lung capacity, and diffusing capacity of the lungs. We used linear mixed models to identify the association of clinical factors with longitudinal changes in lung function at time points before and after treatment completion. Of 80 children who met inclusion criteria, all were treated with bleomycin, and 83.8% received thoracic radiation. More than half (51.2%) of patients had any abnormalities in lung function measures during the study observation period which averaged 24.2 months (±31.1SD). Females, younger age at diagnosis and treatment with radiation were associated with lower lung function measurements at various time points. While the majority of children experienced a recovery of their lung function within 1-2 years after treatment completion, some children with these risk factors did not.

CONCLUSION

Pulmonary function abnormalities begin early in children treated for Hodgkin lymphoma. While the majority of children demonstrate a slow and continuous improvement in lung function back to baseline over time, we recommend routine asymptomatic screening of pulmonary function in certain childhood cancer survivors, particularly females, those diagnosed young and patients who received radiation therapy.

Preserved Long-Term Lung Function in Young Adult Survivors of Common Childhood and Adolescence Malignancies

Purpose: We aimed to evaluate long-term lung function and respiratory outcomes in young adults who survived common pediatric malignancies, treated in a single center. Methods: We enrolled young adults who had been treated during their childhood or adolescence for hematological or solid cancer at our Pediatric Oncology Unit, and performed pulmonary function tests (PFT) and clinical evaluation. PFT included spirometry and Diffusing Capacity of Lung for Carbon Monoxide (DLCO). Results: We included 121 survivors, mean age 23 years at follow-up, median 15 years from diagnosis. The most common diagnoses were hematological malignancies, mainly acute lymphoblastic leukemia, whereas 31% of the patients were treated for nonhematological cancer, mainly neuroblastoma. Treatments consisted of chemotherapy alone or in combination with radiotherapy and/or hematopoietic stem cell transplantation. Most of the patients denied respiratory symptoms throughout the years. In the whole group only eight patients (6%) had abnormal PFT, consisting mainly in a restrictive pattern and reduced DLCO. PFT abnormalities were of mild degree in most of the cases. Overall, the mean values of forced vital capacity, forced expiratory volume in 1 second, and DLCO were normal, but lower in females, in those who received radiotherapy and in those treated for lymphoma. Conclusion: In a group of young adults, surviving the most common childhood malignancies, we found a preserved lung function after a median follow-up of 15 years. The constantly increasing survival in childhood cancer is now associated with a trend toward an improvement in long-term respiratory outcomes.

Exploring pulmonary function and physical function in childhood cancer: A systematic review

BACKGROUND

Children with cancer experience pulmonary and physical function side effects from the cancer itself and the medical interventions. This systematic review examines the known relationship between pulmonary function and physical function in childhood cancer and identifies gaps in the literature.

METHODS

A search of Ovid Medline, CINAHL (EbscoHost) and Embase to identify literature from 2009 to March 2020.

RESULTS

Fifty-seven studies met inclusion criteria. Thirty-seven studies reported impaired pulmonary function. Incidence of pulmonary dysfunction ranged from 45.5 % to 84.1 %. Eighteen studies reported impaired physical function. Three studies investigated the relationship between pulmonary function and physical function. No studies explored inspiratory muscle strength.

CONCLUSION

Pulmonary function and physical function are related and frequently impaired in children during and after cancer treatment. A literature gap was found in diaphragm function and its relationship with physical function. Future studies should focus on interventions that target the pulmonary mechanisms impacting physical function.

Cardiovascular and Pulmonary Challenges After Treatment of Childhood Cancer

Childhood cancer survivors are at risk for developing cardiovascular disease and pulmonary disease related to cancer treatment. This might not become apparent until many years after treatment and varies from subclinical to life-threatening disease. Important causes are anthracyclines and radiotherapy involving heart, head, or neck for cardiovascular disease, and bleomycin, busulfan, nitrosoureas, radiation to the chest, and lung or chest surgery for pulmonary disease. Most effects are dose dependent, but genetic risk factors have been discovered. Treatment options are limited. Prevention and regular screening are crucial. Survivors should be encouraged to adopt a healthy lifestyle, and modifiable risk factors should be addressed.

Early evidence of pulmonary dysfunction in survivors of childhood Hodgkin lymphoma

Survivors of childhood Hodgkin lymphoma (HL) are at risk for pulmonary late effects, but whether survivors also experience pulmonary dysfunction early off therapy is not well understood. We determined the incidence of pulmonary dysfunction in children/adolescents with HL at entry into survivorship, as well as risk factors related to this outcome. Survivors in clinical remission and with a pulmonary function test (PFT) obtained 2-6 years off therapy were included. Seventy-five of 118 subjects met eligibility criteria (mean age at diagnosis: 13 years, mean time off therapy: 40 months). Survivors of HL had a higher than expected incidence of pulmonary dysfunction at entry into survivorship (40/75 [53%] had an abnormal DLCO and/or a restrictive or obstructive impairment). Evidence for diffusion impairment was associated with female sex (odds ratio [OR] = 3.19, p = .04). Longitudinal follow-up studies are needed to determine if early evidence of pulmonary dysfunction predicts risk for later onset pulmonary outcomes.

Impact of Respiratory Developmental Stage on Sensitivity to Late Effects of Radiation in Pediatric Cancer Survivors

Purpose

Pulmonary dysfunction is a prevalent and potentially debilitating late effect of pediatric cancer treatment. We postulated that age, as a surrogate for respiratory developmental status, might be associated with vulnerability to pulmonary injury.

Materials and Methods

Sixty-one children treated with lung radiation at our institution who had undergone a pulmonary function test (PFT) between 1995 and 2016 were analyzed. Data collection included age at diagnosis and treatment, radiation dose and location, spirometry, and plethysmography results. PFTs were normalized according to age, sex, height, and ethnicity, and transformed into standardized z-scores. Obstructive disease was defined as forced expiratory volume in 1 second z score/forced vital capacity z score < −1.645, restrictive as total lung capacity z score < –1.645, and abnormal diffusion as diffusing capacity of the lung for carbon monoxide z score < −1.645. We determined the incidence of PFT abnormalities in our population and estimated the relative risk of developing pulmonary abnormalities using models adjusted for age.

Results

At a mean age of 24 years (range, 12-31) and time from radiation of 9 years (range, 1-20), the cumulative incidence of any pulmonary abnormality was 34.4%. Among patients with an abnormal PFT, diffusing and restrictive abnormalities were most common (57.1% and 52.4%). When stratified by age at radiation treatment, 66.7% of patients <5 years had a PFT abnormality, compared with 47.6% for aged 5 to 13 and 20.6% for patients >13. Compared with patients >13 years, those <5 years and 5 to 13 years at radiation treatment had a significantly increased risk of an abnormal PFT with an odds ratio of 7.71 (95% confidence interval, 1.17, 51.06) and 3.51 (95% confidence interval, 1.06, 11.57), respectively (P <. 035). Furthermore, this association remained when examining each type of abnormality (P > .05).

Conclusions

PFT abnormalities were common among our cohort of childhood cancer survivors treated with lung radiation. Younger age at treatment is associated with an increased risk of developing pulmonary dysfunction, presumably owing to developmental immaturity.

Long-term morbidity of respiratory viral infections during chemotherapy in children with leukaemia

BACKGROUND

Respiratory viruses are a common cause of infection in immunosuppressed children undergoing cancer therapy. Pulmonary sequelae have been documented following respiratory viral infections (RVIs) in hematopoietic stem cell transplant (HSCT) recipients; however potential late effects in children undergoing nonmyeloablative chemotherapy have not been investigated.

AIM

To evaluate the long-term pulmonary morbidity of respiratory viral infections during chemotherapy in children with acute lymphoblastic leukemia (ALL).

METHODS

Childhood ALL survivors, aged 7 to 18 years, greater than 6 months posttreatment were recruited. Exclusion criteria included HSCT or proven bacterial/fungal respiratory infection during treatment. Subjects were classified into "viral" or "control" groups according to retrospective medical records that documented the presence of laboratory-proven RVIs during chemotherapy. Symptom questionnaires (Liverpool, ISAAC) and lung function testing (spirometry, plethysmography, diffusing capacity, forced oscillation technique to ATS/ERS standards) were then performed cross-sectionally at the time of recruitment.

RESULTS

Fifty-four patients (31 viral, 23 control) were recruited: median (range) age 11.2 (7.2-18.1) years, and at 4.9 (0.5-13) years posttherapy. Abnormalities were detected in 17 (31%) individuals (8 viral, 9 control), with the most common being DLCO impairment (3 viral, 4 control) and reduced respiratory reactance at 5 Hz (5 viral, 6 control). Children with RVIs during chemotherapy reported more current respiratory symptoms, particularly wheeze (odds ratio [OR], 3.0; 95% confidence interval [CI]: 0.9-10.0; P = .09) and cough (OR, 2.7; 95% CI: 0.8-9.5; P = .11). No differences in lung function tests were observed between the two groups.

CONCLUSIONS

Our study found children with RVIs during chemotherapy developed more long-term respiratory symptoms than controls; however, differences did not reach statistical significance. No differences in static lung function were found between the two groups. Overall, pulmonary abnormalities and/or significant ongoing respiratory symptoms were detected in nearly a third of ALL survivors treated without HSCT. Larger, prospective studies are warranted to evaluate the etiology and clinical significance of these findings.

Busulfan-Induced Lung Injury in Pediatric Oncology Patients-Review of the Literature with an Illustrative Case

Background: Impaired lung function has been detected in up to 65% of all childhood cancer survivors. It is often caused by exposure to radiation therapy and various chemotherapeutics. The first cytotoxic drug ever identified as a causative agent of lung injury was busulfan, reported in the early 1960s. Signs and symptoms of busulfan lung are nonspecific and it is therefore difficult to differentiate the condition from pulmonary impairment caused by other pulmotoxic agents, infections, pulmonary metastases, graft-versus-host disease, or other noninfectious post-transplant complications involving the lungs. Methods: A case example is provided to illustrate the difficulties in management of busulfan-induced lung injury in children. A retrospective review of cases of busulfan-induced lung injury indexed in PubMed until March 2019 was performed. Inclusion criteria for articles was available in full text in English. Results: Impaired lung function caused by busulfan may become an increasing problem for young survivors. Conclusion: Newly developed dyspnea or subclinical damage detected on pulmonary function tests, indicating primarily restrictive disease, should always arouse suspicion of busulfan-induced lung injury in a child conditioned with busulfan, especially after excluding other leading culprits of pulmonary damage affecting oncology patients.

Respiratory morbidity in young people surviving cancer: Population-based study of hospital admissions, treatment-related risk factors and subsequent mortality

Respiratory diseases are a major cause of late morbidity and mortality amongst childhood cancer survivors. This population-based study investigates respiratory hospital admissions in long-term survivors of cancers diagnosed in young people to identify specific respiratory morbidities, treatment-related risks and their relationship to subsequent morbidity and mortality. Population-based cancer registrations in Yorkshire, England, diagnosed between 1990 and 2011 aged 0-29 years, were linked to inpatient Hospital Episode Statistics (HES) for admissions up to 2017. All 5-year survivors were included in analysis (n = 4235). Admission rates were compared to age- and sex- matched general population rates. Competing risk regression models were used to assess associations between treatment exposures and risk of admission. Risk of death after admission was calculated using Cox regression. By age 40, cumulative incidence for an admission for any type of respiratory condition was 49%. Respiratory admission rates were 1.86 times higher in cancer survivors than in the general population (95% Confidence Interval (CI) 1.73-2.01), and varied by respiratory condition and age at diagnosis. Treatment with chemotherapy with known lung toxicity increased the risk of admission for all respiratory conditions (subdistribution Hazard ratio (sHR) = 1.26, 95%CI 1.03-1.53) and pneumonia (sHR = 1.48, 95%CI 1.01-2.17). Subsequent mortality was highest in those admitted for pneumonia compared to other respiratory conditions (28% and 15% respectively). Survivors of childhood and young adult cancer remain at significantly increased risk of respiratory complications several decades after treatment, emphasising the importance for clinical initiatives for prevention, early detection and treatment.

Skeletal Muscle Dysfunction and Exercise Intolerance in Children Treated with Haematopoietic Stem Cell Transplant-A Pilot Feasibility Study

Haematopoietic stem cell transplant (HSCT) is an intensive therapy for some pediatric hematological illnesses. Survivors are at risk for adverse effects including exercise intolerance. Peripheral tissue dysfunction may contribute to exercise intolerance; therefore, we examined the feasibility of a magnetic resonance spectroscopy (MRS) protocol to evaluate skeletal muscle metabolism in children post-HSCT. We measured demographic characteristics, aerobic exercise capacity (YMCA protocol), and skeletal muscle function in response to exercise (MRS; Siemens 3T MRI) in five children post-allogeneic HSCT and five age/body mass index-matched healthy controls (HCs). The mean age (± standard deviation) of the HSCT group and HC group were 11 ± 1.2 and 12.8 ± 2.4 years, respectively. Children post-HSCT had a lower peak aerobic exercise capacity compared to HCs (27.8 ± 3.4 vs. 40.3 ± 8.1 mL kg⁻¹ min⁻¹, respectively; p = 0.015). Exercise MRS testing protocols were successfully completed by all HSCT and HC participants; however, MRS-derived skeletal muscle metabolism variables were not different between the two groups. In conclusion, the use of exercise protocols in conjunction with MRS to assess peripheral skeletal muscle metabolism was achievable in children post-HSCT. In the future, larger studies should determine if skeletal muscle function is associated with exercise capacity in children post-HSCT.

Long-term pulmonary disease among Swiss childhood cancer survivors

BACKGROUND

Pulmonary diseases are potentially severe late complications of childhood cancer treatment that increase mortality risk among survivors. This nationwide study assesses the prevalence and incidence of pulmonary diseases in long-term childhood cancer survivors (CCS) and their siblings, and quantifies treatment-related risks.

METHODS

As part of the Swiss Childhood Cancer Survivor Study, we studied CCS who were diagnosed between 1976 and 2005 and alive at least 5 years after diagnosis. We compared prevalence of self-reported pulmonary diseases (pneumonia, chest wall abnormalities, lung fibrosis, emphysema) between CCS and their siblings, calculated cumulative incidence of pulmonary diseases using the Kaplan-Meier method, and determined risk factors using multivariable logistic regression.

RESULTS

CCS reported more pneumonias (10% vs. 7%, P = 0.020) and chest wall abnormalities (2% vs. 0.4%, P = 0.003) than siblings. Treatment with busulfan was associated with prevalence of pneumonia (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.1-14.9), and thoracic surgery was associated with chest wall abnormalities and lung fibrosis (OR 4.1, 95% CI 1.6-10.7 and OR 6.3, 95% CI 1.7-26.6). Cumulative incidence of any pulmonary disease after 35 years of follow-up was 21%. For pneumonia, the highest cumulative incidence was seen in CCS treated with both pulmotoxic chemotherapy and radiotherapy to the thorax (23%).

CONCLUSION

This nationwide study in CCS found an increased risk for pulmonary diseases, especially pneumonia, while still young, which indicates that CCS need long-term pulmonary follow-up.