Multiple-breath washout identifies pulmonary dysfunction in childhood cancer survivors

Nitrogen multiple-breath washout identified more cases of pulmonary dysfunction in childhood cancer survivors compared with spirometry, researchers reported in the Annals of the American Thoracic Society.

“[Nitrogen multiple-breath washout] has to date been investigated only in pediatric patients with cancer undergoing hematopoietic stem cell transplantation. This is the first study that shows results of nitrogen multiple-breath washout tests in long-term survivors of childhood cancer,” Christina Schindera, MD, PhD student in the department of pediatric oncology/hematology and pediatric respiratory medicine at the University Children’s Hospital Basel, Switzerland, and colleagues wrote. “We found that more than half of childhood cancer survivors had some signs of pulmonary dysfunction.”

Schindera and colleagues analyzed cross-sectional data on 46 survivors of childhood cancer ( 5 years’ survival). All were aged 16 years or younger at the time of cancer diagnosis (median age, 10 years) and were aged 16 years or older during the current study period (median age, 30 years). More than half of the patients received treatment for leukemia and one-quarter for lymphoma. All survivors were free from asthma, preexisting pulmonary disease and chronic respiratory symptoms at the time of study.

Childhood cancer survivors were categorized as high risk (37%) or standard risk (63%). Survivors in the high-risk group had a history of pulmotoxic chemotherapy, chest radiation, thoracic surgery and/or hematopoietic stem cell transplantation. Those in the standard-risk group received other cancer therapies.

Researchers compared pulmonary dysfunction between both groups. Pulmonary dysfunction was defined as z score +1.64 for nitrogen multiple-breath washout and –1.64 for spirometry.

The primary outcomes were global lung clearance index and acinar ventilation inhomogeneity index from nitrogen multiple-breath washout and FEV₁ and FVC from spirometry.

Lung clearance index and acinar ventilation inhomogeneity index were higher in the high-risk group (2.09 vs. 2.45, respectively) compared with the standard-risk group (0.95 vs. 0.65, respectively). FEV₁ and FVC were both lower in the high-risk group (–0.94 vs. –1.14, respectively) compared with the standard-risk group (–0.1 vs. 0.15, respectively).

Lung clearance index was abnormal in 60% of high-risk patients vs. 23% of standard-risk patients, acinar ventilation inhomogeneity in 53% vs. 21%, respectively, FEV₁ in 33% vs. 0%, respectively, and FVC in 33% vs. 4%, respectively.

According to the researchers, further study of childhood cancer survivors is needed, specifically longitudinal assessments and sensitive surveillance of pulmonary function in patients previously deemed as facing standard risk.

“Because nitrogen multiple-breath washout identified more cases of pulmonary dysfunction than spirometry, we believe nitrogen multiple-breath washout could be a complementary technique — for patients of all ages — for the screening of childhood cancer survivors for pulmonary damage,” the researchers wrote.