Analysis of risk factors for the development of a post-bronchoscopy respiratory infection in lung cancer patients

Abstract Background: The development of pneumonia following bronchoscopy is very important as a post-bronchoscopy complication. Most patients with post-bronchoscopy respiratory infections show typical pneumonia, and lung abscesses are rare. However, bronchoscopic techniques have advanced, and recently, we have observed patients with lung abscess after bronchoscopy. Therefore, the risk factors might vary from those in past reports. This study aims to identify the incidence of and risk factors for post-bronchoscopy respiratory infections. Methods: We retrospectively studied adult patients diagnosed with lung cancer by bronchoscopy at Fukujuji Hospital between January 2017 and June 2019. Patients in the infection and noninfection groups were compared. The incidence of lung abscess was compared between recent periods and 2013, when endobronchial ultrasonography with a guide sheath (EBUS-GS) was not yet used in our hospital. Results: We reviewed 327 patients, including 20 patients (6.1%) in the infection group. The risk factors for infection were necrosis and/or a cavity in the tumor (p<0.001), large tumor diameter (≥30 mm) (p=0.003), and low serum albumin (<4.0 g/dL) (p=0.012). We developed a predictive score that included these risk factors, and the area under the curve of the score was 0.737 (95% Cl: 0.610-0.864). Conversely, no significant differences in age, current smoking status, or abnormal bronchoscopic findings were observed, even though these factors were reported as risk factors in past reports. Other risk factors for infection were a high white blood cell count (p=0.007), high C-reactive protein level (p=0.014), and expression of programmed death-ligand 1 expression in the tumor cells (p=0.033). In total, 12 patients had lung abscesses (3.7%), which represents a higher incidence than that in 2013 (0.8%). Other types of infection were post-obstructive pneumonia in four patients (1.2%) and typical pneumonia in four patients (1.2%). Conclusions: The risk factors for developing post-bronchoscopy respiratory infection in our study varied from those in past reports, possibly because of the advancement of bronchoscopic techniques such as EBUS-GS.