Abstract
Cardiorespiratory fitness (CRF) is a robust and independent predictor of cardiovascular health and overall mortality. Patients with lung cancer often have chronic lung disease, contributing to impaired CRF. Radiation to the heart during lung cancer treatment may further reduce CRF. The determinants of CRF in this population are not well understood. We prospectively evaluated 12 patients with lung cancer without known cardiovascular disease with reduced lung function receiving curative intent thoracic radiotherapy to determine whether cardiac diastolic function, as assessed by Doppler echocardiography and N-terminal pro-brain natriuretic peptide (NTproBNP) levels, correlate with CRF measured by peak oxygen consumption (VO(2)). Doppler-derived measures of diastolic function and serum NTproBNP levels inversely correlated with peak VO(2.) In a multivariate regression model, NTproBNP was the strongest independent variable associated with peak VO(2). These results suggest that diastolic dysfunction further contributes to reduced CRF in patients with lung cancer who have received radiotherapy.