The final staging system for NSCLC was made in 2007 (Table 2): the extent of disease is based on tumor size (T), lymph node involvement (N), and distant metastasis (M). Good staging can stratify patients into homogeneous groups with prognosis, prognosis in treatment decision making, and allow for more accurate comparison of treatment strategies and prognoses. Even for patients ineligible for surgery, staging is essential for administering other treatment procedures such as chemotherapy or radiotherapy and predicting prognosis. TNM classification in NSCLC includes eight stages: IA, IB, IIA, IIB, IIIA, IIIB, IV and 0 stages. Stage I and II (early stage) lung cancer is close to resection. Patients with stage III (locally advanced) tumors may be candidates for surgery depending on the characteristics of local invasion. If the tumor has infiltrated the superior vena cava or the carina, resection may be performed in some cases. But other mediastinal structures; Resection often becomes impossible if there is involvement of the esophagus, great vessels, or heart, or undesirable levels of nodal involvement.

1. T (Primary tumor):
   – Failure to detect Tx primary tumor or detecting malignant cells in sputum or bronchial lavage and failing to show the tumor by imaging techniques or bronchoscopy.
   – No evidence of T0 primary tumor.
   – Tis carcinoma in situ.
   – T1 largest diameter ≤3 cm. Tumor surrounded by lung or visceral pleura, with no bronchoscopic evidence of invasion more proximal than the lobe bronchus (eg, no invasion of the main bronchus)*.
   – T1a tumor ≤2 cm in greatest diameter.
   – T1b tumor greater than 2 cm in diameter. but ≤3 cm.
   – The largest diameter of the T2 tumor is >3 cm. but ≤7 cm. or the tumor must have at least one of the following features:
   • The main bronchus is involved, but the distance from the carina is ≥2 cm.
   • Visceral pleural invasion.
   • Tumor spreading to the hilar region causing atelectasis or obstructive pneumonia that does not involve the entire lung.
   – T2a tumor greater than 3 cm in diameter. but ≤5 cm.
   – T2b tumor greater than 5 cm in diameter. but ≤7 cm.
   – The largest diameter of the T3 tumor is >7 cm. or chest wall (including tumors of the superior sulcus), diaphragm, phrenic nerve, mediastinal pleura, parietal pericardium, or tumor in the main bronchus closer than 2 cm to the carina but not involving the carina, or atelectasis involving the whole lung, or obstructive pneumonia associated tumor or a different tumoral nodule(s) in the same lobe as the tumor.
   – T4 tumor of any size, invading any of the structures such as the mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, carina; the presence of a different tumoral nodule(s) in a different lobe in the same lung as the tumor. 2. N (Regional lymph nodes):
   – Failure to evaluate Nx regional lymph nodes.
   – No N0 regional lymph node metastasis.
   – N1 ipsilateral peribronchial and/or ipsilateral hilar lymph node involvement and intrapulmonary gland involvement with direct spread of the primary tumor.
   – N2 metastases to ipsilateral mediastinal and/or subcarinal lymph nodes.
   – N3 contralateral mediastinal, hilar; ipsi or contralateral supraclavicular or scalene lymph node metastasis.
2. M (Distant metastasis):
   – Inability to evaluate the presence of Mx distant metastases.
   – M0 no distant metastases.
   – There is M1 distant metastasis.
   – Different tumoral nodule(s) in the lung versus M1a; Tumor with pleural nodules or malignant pleural (or pericardial) effusion.
   – M1b distant metastasis.
   A rare superficial spreading tumor of any size with limited invasion of the bronchial wall extending proximal to the main bronchus is also classified as T1.
   Most pleural (or pericardial) effusions associated with lung cancer are due to the tumor. However, in some patients, the tumor cannot be detected on repeated cytological examinations of the pleural fluid. In these cases, the fluid is not bloody and is not exudate. If the clinical situation and the characteristics of the fluid are not suggestive of a tumor, the fluid should not be considered in staging and the patient should be evaluated as T1, T2, T3 or T4.

According to this distribution, the N , T and M distributions are shown in the table below:

N0 N1 N2 N3 T1a (<2 cm.) IA IIA IIIA IIIB T1b (2-3 cm.) IA IIA IIIA IIIB T2a (3-5 cm.) IB IIA IIIA IIIB T2b (5-7 cm.) IIA IIB IIIA IIIB T3 (7 cm.) IIB IIIA IIIA IIIB T3 invasion IIB IIIA IIIA IIIB Identical lobe nodule IIB IIIA IIIA IIIB T4 Diffuse invasion IIIA IIIA IIIB IIIB Other lobe nodule IIIA IIIA IIIB IIIB M1a (Pleural fluid) IV IV IV IV Contralateral lung nodule IV IV IV IV M1b (Distant metastasis) IV IV IV IV Based on these data, the IASLC recommends the following new stages: – Occult carcinoma Tx N0 M0 – Stage 0 Tis N0 M0 – Stage IA T1a N0 M0 T1b N0 M0 – Stage IB T2a N0 M0 – Stage IIA T1a N1 M0 T1b N1 M0 T2a N1 M0 T2b N0 M0 – Stage IIB T2b N1 M0 T3N0 M0 – Stage IIIA T1 N2 M0 T2N2 M0 T3N1 M0 T3N2 M0 T4N0 M0 T4N1 M0 N3 M0 Any Home – Stage IV Any T Any N M1a, Any T Any N M1b