Table 2. Eligibility criteria for study selection process according to PICOS guidelines.

PICOS guidelines	Eligibility criteria	Exclusion criteria
Patients	Patients that underwent curative-intent lung surgery for NSCLC. Patients with theoretical indication of AC or patients who received AC	Patients with advanced or metastatic NSCLC were excluded
		Articles that enrolled only patients with stage I NSCLC disease were excluded
		Patients with other histologic sub-types (i.e., small-cell lung cancer, large cell neuroendocrine lung carcinoma, carcinoid tumours, malignant pleural mesothelioma and other cancers) were excluded
Intervention	AC in real-life practice	Neoadjuvant strategies and other adjuvant strategies (i.e., targeted therapies, immunotherapy, other chemotherapy regimens) were excluded
		Other studies dealing with treatments part of the multimodal strategy (i.e., surgery, radiotherapy, concomitant or sequential chemotherapy) were excluded
Comparison	No control group defined for intervention	–
Outcomes	No primary or secondary endpoints were defined	–
Study design	Prospective or retrospective observational studies on AC use in real-life practice for resected NSCLC. As the first randomized clinical trial on AC was published in 2004, study eligibility criteria also included period of publications from 2004 to 2021	Randomized clinical trials and sub-group analysis on AC out of the context of real-life practice were excluded
		Reviews and meta-analysis about lung cancer and AC out of the context of real-life practice were excluded
		Articles dealing with predictive and prognostic markers in lung cancer, pre-clinical studies, guidelines and case report on lung cancer were excluded

NSCLC, non-small cell lung cancer; AC, adjuvant chemotherapy.