Changes in pulmonary function and influencing factors after high-dose intrathoracic radio(chemo)therapy.

Abstract

Using prospectively collected patient-related, dose-related, and pulmonary function test (PFT) data before radiotherapy (RT) and at several follow-up visits after RT, the time course of PFT changes after high-dose radio(chemo)therapy and influencing factors were analyzed. From April2012 to October2015, 81patients with non-small-cell lung carcinoma (NSCLC), small cell lung carcinoma (SCLC), or esophageal carcinoma where treated with high-dose radio(chemo)therapy. PFT data were collected before treatment and 6weeks, 12weeks, and 6months after RT. The influence of patient- and treatment-related factors on PFT was analyzed. Mean forced expiratory volume in 1s (FEV1) constantly declined during follow-up (p= 0.001). In total, 68% of patients had areduced FEV1 at 6months. Mean vital capacity (VC) didn't change during follow-up (p> 0.05). Mean total lung capacity (TLC) showed aconstant decline after RT (p= 0.026). At 6months, 60% of patients showed adecline in VC and 73% in TLC. The mean diffusion capacity for carbon monoxide (DLCO) declined at 6 and 12weeks, but recovered slightly at 6months (p< 0.0005). At 6months, 86% of patients had areduced DLCO. After treatment, the partial pressure of CO2 in the blood (pCO2) was increased and pO2 was decreased (p> 0.05). Only the pretreatment PFT classification had asignificant influence on the post-RT FEV1. DLCO seems to be the most reliable indicator for lung tissue damage after thoracic RT. Ventilation parameters appear to be less reliable. Concerning patient- or treatment-related factors, no reliable conclusion can be drawn regarding which factors may be relevant.