2.1. Study Population and Data Collection

This was a retrospective cohort study. We screened the medical data of patients with non-small cell lung cancers (NSCLC) who underwent lung resection surgery between January 2010 and December 2016 from the Lung Cancer Surgery Registry at Samsung Medical Center, a 1997 bed referral hospital in South Korea. Patients with a concurrent diagnosis or a previous history of NTM-PD at the time of surgery were excluded. Even when the diagnostic criteria for NTM-PD were not fully satisfied, patients with culture-positive NTM from the respiratory specimen obtained before surgery were also excluded. Additionally, patients who showed granulomatous inflammation in surgical specimens of lung cancer in which NTM infection could not be ruled out were excluded from this study.

We used the same database to gather the following information: patient-related factors, such as age, sex, body mass index (BMI), a history of smoking, underlying pulmonary diseases, other comorbidities, and CT findings at the time of the lung cancer diagnosis (TB sequelae, bronchiectasis, and centrilobular bronchiolitis); cancer-related factors, such as histologic type, location of the tumor, and the clinical/pathological stage of cancer; treatment-related factors, including the neoadjuvant or adjuvant treatments used, the surgical approach, the extent of surgical resection, and the development of any PPCs within 30 days after surgery. Underlying pulmonary diseases included a previous history of pulmonary TB, small airway disease (COPD, asthma), and ILD. The tumor was staged using the Seventh Edition of the American Joint Committee on Cancer [19]. A PPC was defined as the development of any intrathoracic complications during the patient’s hospital stay or during a readmission within 30 days after surgery [20]. Patient follow-up data were last updated in February 2021.

This study obtained approval from the Institutional Review Board (IRB no. 2021-04-016) to review and publish information from patient records, and the requirement for informed consent was waived because the patient information was de-identified and anonymized prior to the retrospective analysis.