Stage I includes: IA: (T1, N0, M0); IB: (T2 or T3, N0, M0). T1: Tumor limited to the ipsilateral parietal with or without involvement of visceral pleura, mediastinal pleura, and diaphragmatic pleura. T2: Tumor involving each of the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura) with at least one of the following features: involvement of diaphragmatic muscle and/or extension of tumor from visceral pleura into the underlying pulmonary parenchyma. T3: Tumor is locally advanced but potentially resectable. The tumor involves all the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura) with at least one of the following features: involvement of the endothoracic fascia, extension into the mediastinal fat, solitary, completely resectable focus of tumor extending into the soft tissues of the chest wall, and/or nontransmural involvement of the pericardium. N0: No regional lymph node metastases. M0: No distant metastasis. (AJCC 8th ed.) [from NCI]