Nonsmall Cell Carcinoma Staging

The stages are depicted in Table 12.1. These are Stage I, II, III and IV. The 5 year disease free survival for stage I is in the range of about 85%; that for stage II is 60%; that for all types of stage III is about 30%; and that for stage IV less than 10%. The stages are identified by various classifications within the TNM system. T-1 is a lesion less than 3 cm without invasion of the visceral pleura. T-2 is a lesion greater than 3 cm or any sized tumor that invades the visceral pleura or has associated atelectasis or obstructive pneumonitis extending to the hilar region. T-3 is a tumor of any size with direct extension into nonessential chest structures. This includes invasion into the chest wall (including superior sulcus tumors), diaphragm, mediastinal pleura, and pericardium without heart involvement. Also a tumor in the mainstem bronchus within 2 cm of the carina but not involving the carina is a T-3 lesion. A T-4 lesion denotes invasion of essential mediastinal structures. These include heart, great vessels, vertebral body, esophagus, trachea or carina. Also the presence of a malignant pleural effusion is a T-4 lesion.

The nodal classification is as follows: N-0 means no nodal involvement. N-1 implies bronchopulmonary nodes according to the old classification system. These include any nodes within the visceral pleural envelope. N-2 nodes involve tracheobronchial nodes according to the old classification system, i.e. mediastinal nodes outside of the visceral pleural envelope. N-3 nodes are contralateral mediastinal nodes, contralateral hilar nodes, or ipsilateral or contralateral scalene or supraclavicular lymph nodes. The presence of metastases indicates M-1 disease.

The following is a redefined staging classification as instituted by Mountain in 1997. Stage I is a T-1 or T-2 lesion without nodal involvement (Fig. 12.1 a-b) or a T-2 lesion with N-1 pulmonary node involvement. Additionally, a T-3 lesion without nodal involvement is now considered a Stage II lesion. This is the most important change of Mountain's new classification compared to pre-1997 classification schemes. Previously T-3, N-0 lesions were classified as Stage III leasions, but with appropriate theraoy it became clear that these T-3, N-0 lesions had a far better prognosis than their Stage III counterparts, prompting the change to Stage II.

Stage III represents a far more grave category. Stage IIIa is T-3 disease with intrapulmonary (N-1) lymph node involvement or any mediastinal (N-2) involvement. Surgery may still be offered in T-3, N-1 disease, e.g., superior sulcus tumors with N-1 nodes not extending to the mediastinum. Generally, surgery is not offered for lung carcinoma with N-2 mediastinal involvement. Stage IIIb implies

Table 12.1. Staging of NSCLC

Stage

Survival

b T2, N1 or T5 NO TS, N1, or Any N2 Any T4 or Any N M

Chance for surgical management

Medical management

T2 > 3 cm or invading visceral pleura or obstructing atelectasis/pneumonitis T3 invading nonessential mediastinal structures or within 2 cm of carina T4 invading essential mediastinal structures or malignant pleural effusion

N1 intrapulmonary nodes N2 ipsilateral mediastinal nodes N3 contralateral nodes; ipsilateral or contralateral supraclavicular nodes.

Chance for surgical management unresectability and includes either a T-4 or N-3 lesion. A Stage IV lesion is any lesion with metastases.

Generally, Stages I and II are managed primarily by surgical resection. Stage Ilia lesions may or may not be managed surgically. Examples of lesions that can be resected surgically include superior sulcus tumors or other peripheral lung tumors with chest wall involvement (Fig. 12.2a-b). However, N-2 lesions involving the mediastinal nodes are generally considered unresectable, yet these are still Stage IIIa lesions. Stage IIIb lesions and Stage IV lesions are generally considered unresectable.

What about recurrent laryngeal nerve involvement or phrenic nerve involvement? Does this imply an unresectable tumor? Frequently, lesions involving the recurrent laryngeal nerve are in the aortopulmonary window and involve the mediastinal nodes in positions 5 and 6, near the recurrent nerve on the left side. Some feel that this may be resectable but most surgeons feel that this is an unresectable lesion. With regard to phrenic nerve involvement, this may be resec-table if only the pericardium is involved without actual extension onto the heart. A malignant pleural effusion implies an unresectable T-4 lesion which is a Stage IIIb.

Fig 12.1. CXR (a-left) and CT scan (b-right) of a patient with a large T2 lung tumor. The staging remains Stage I because there is no other apparent invasion or nodal involvement. Because of the size of the lesion, it is in Stage Ib.

Fig 12.2. CXR (a-left) and CT scan (b-right) of a patient with a T3 lung tumor with chest wall involvement. If subsequent lobectomy revealed no intrapulmonary nodes (N0), it would be Stage IIb; if there were intrapulmonary nodes (N1) it would be Stage IIIa.

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