Changes in pulmonary function after definitive radiotherapy for NSCLC.

Abstract

The objective of this study was to identify factors associated with early and long-term pulmonary function (PF) changes after definitive radiotherapy for NSCLC patients. PF was measured by spirometry i.e. forced expiratory volume in 1s (FEV1), and forced vital capacity (FVC). Early (within the first year) PF change was analyzed in 211 patients with 986 pairs of PF-tests (PFTs). Long-term PF change was analyzed relative to the PF at 12months after radiotherapy in 106 patients (1286 PFTs). To investigate the impact of patient and treatment related factors on PF, they were tested as covariates in multivariable analysis. Early PF change was quantified at six months after the start of radiotherapy. Smoking status and increasing V60 was associated with a significant decrease in PF, whereas smoking was protective. In addition, neoadjuvant chemotherapy had a negative impact on FVC. Long-term FEV1 and FVC were analyzed using linear regression. Treatment year and V60 had a significant impact on loss of FEV1. V60 had a significant impact on FVC changes. In this study, early PF change reached a plateau at 6months after the start of radiotherapy for NSCLC. Large volume of lung receiving high dose was associated with long-term FEV1 change.