Multi-institution retrospective study of the onset frequency of postoperative pneumonia in thoracic esophageal cancer patients

Background: Esophagectomy for thoracic esophageal cancer is a highly invasive procedure. Most studies analyzing the risk factors for pulmonary morbidity were conducted in the early 1990s. However, previous studies did not use fixed diagnostic criteria for postoperative pneumonia and reported widely varying onset frequencies. Purpose: To define postoperative pneumonia diagnostic criteria, clarify the onset frequency of postoperative pneumonia after esophagectomy in accordance with these criteria, and investigate the risk factors of postoperative pneumonia. Methods: Risk factors for postoperative pneumonia were analyzed in 615 patients who underwent esophagectomy between January 2006 and December 2007 at 7 Japanese institutions using logistic regression models. The necessary criterion for a pneumonia diagnosis was an infiltrative shadow on a chest radiograph. Furthermore, a pneumonia diagnosis was based on the presence of at least 2 of the following 3 criteria: white blood count abnormalities, body temperature of 38°C or higher, and purulent sputum. Results: Overall, 615 patients were statistically analyzed. Pneumonia onset occurred in 66 cases (10.7 %). The risk of postoperative pneumonia was associated with a preoperative body weight loss of 5 % or more and late tracheal tube extubation. Conclusions: This study revealed that preoperative body weight loss increased the risk of postoperative pneumonia after esophagectomy for esophageal cancer, while early-stage tracheal tube extubation reduced the risk.