Cohort profile: pulmonary early assessment of the lung in paediatric cancer patients (SWISS-PEARL Study).

Background: Due to the limited sensitivity of conventional lung function tests in detecting small airway abnormalities, cancer treatment-related pulmonary toxicity may be underdiagnosed. It has been suggested that the nitrogen multiple-breath washout test (N2MBW) might be more sensitive in detecting small airway abnormalities in childhood cancer survivors.

Objective: The Pulmonary Early Assessment of the Lung in Paediatric Cancer Patients (SWISS-PEARL) study aims to assess the prevalence and development of early pulmonary toxicity at baseline and longitudinally in paediatric cancer patients using spirometry, body plethysmography, diffusing capacity for carbon monoxide (DLCO), N2MBW and magnetic resonance imaging (MRI) and to identify treatment-related pulmotoxic risk factors.

Methods: This prospective, multicentre, cohort study at the University Children's Hospitals of Basel, Bern, Lausanne and Zurich, is enrolling patients aged ≥4 and <22 years at study entry exposed to at least one of the following cancer treatments: chest radiation, chemotherapy or targeted agents, haematopoietic stem cell transplantation and/or thoracic surgery. Participants perform comprehensive lung function testing at baseline (i.e. within 28 days of the start of systemic cancer treatment) and during four follow-up visits until two years after the end of intensive treatment. Respiratory symptoms are also assessed at each time point, and MRI is planned at one and two years post-treatment.

Results: Since May 2022, we have recruited 44 patients and performed 134 lung function tests at baseline. Mean age at diagnosis was 12 years (range 4-18). The most common cancer diagnoses were leukaemia (41%) and lymphoma (23%). Pulmonary assessment was feasible and of good quality in 43/44 (98%) patients for at least one test at baseline; only 4 patients dropped out after baseline measurements.

Conclusion: This study will assess the potential development of early pulmonary dysfunction during and post-treatment. Findings from the SWISS-Pearl study may help inform future guidelines for pulmonary surveillance in paediatric cancer patients.