Assessment of pulmonary function test abnormalities in adult survivors of childhood cancer.

Abstract

117 Background: As childhood cancer survival approaches 85%, it is increasingly recognized that childhood cancer survivors (CCS) are at risk for long-term therapy-related complications. Data suggest that pulmonary function test (PFT) abnormalities occur in as many as 84.1% of CCS. Our aim was to assess the prevalence and nature of respiratory abnormalities in adult CCS and to correlate these abnormalities with therapeutic exposures and health behaviors. Methods: Patients who received pulmonary toxic therapy routinely undergo PFTs at their first visit to the POGO AfterCare clinic in Ottawa, Canada. We conducted a retrospective review of all patients seen in clinic from August 2015 until December 2016. PFT results, treatment exposures and health habits were documented. We used NHANES-III prediction equations for PFT interpretation, with expiratory flows and lung volumes of ≥80% predicted as cutoffs for normal. Results: Of a total of 200 patients, 48 received pulmonary toxic therapy and 38 underwent PFTs. Mean age at the time of PFT was 28.8 years (18.5-57.5 years) and the mean time from diagnosis was 17.4 years (3.4-47.5 years). Although no patients reported respiratory symptoms, 42% (16/38) demonstrated a mild restrictive ventilatory defect, 11% (4/38) had mild airflow obstruction, 18% (7/38) had an isolated reduction in diffusion capacity and 1 patient had a moderate mixed obstructive/restrictive abnormality. Only 26% (10/38) had normal lung function. Of those with restrictive defects, all received radiation and 50% were also exposed to pulmonary toxic chemotherapy. All patients with obstructive defects received radiation therapy in combination with bleomycin. Tobacco or marijuana use was reported in 26% (10/38) of the cohort, and in 29% (8/28) of those with PFT abnormalities. Conclusions: PFT abnormalities are common among adult CCS who received pulmonary toxic therapy. Studies evaluating the change in pulmonary function abnormalities over time and their correlation to cardiopulmonary exercise testing and lung imaging are required to inform the health impact on these survivors.