Lung Cancer Stages | Diagnosis of Stages of Lung Cancer

Stages of Lung Cancer

The concept of staging arose from the fact that survival rates were better for malignancies that were localized than for those which had a metastasized at the time of clinical presentation. This was associated with the concept of early and late presentation, implying the regular progression with the time.

The grading of the cancer attempts to establish some estimates of its aggressiveness or level of malignancy based on the cytologic differentiation of tumor cells and the number of mitosis within the tumor.

Cancer may be classified as grade I, II, III and IV, in order of increasing anaplasia.

Staging of cancers is based on the size of the primary lesion, its extent of spread to regional lymph nodes and the presence or absence of metastasis. This assessment is usually based on clinical and radiographic examination and in some cases surgical exploration.

Two methods are currently in use, the TNM system (T for tumor, N for regional lymph node involvement and M for metastasis) and the AJC (American joint committee) system.

TNM system is widely used in practice and staging are as follows

Staging of Lung Cancer

As with other cancers, tumor-node-metastasis (TNM) classification has been established to indicate the size and spread of primary neoplasm.

In the TNM system T1, T2, T3 and T4 respectively, describe the increasing size of the primary lesion; N0, N1, N2 or N3 indicates progressively advancing node involvement; and M0 and M1 reflect the presence or absence of distant metastasis. Some concept of the system can be derived from the following abbreviated version.

Occult

No clinical or radiographic evidence of the primary tumor or of spread, but broncho-pulmonary secretions contain malignant cells (TX N0 M0).

Lung Cancer Stage I

A tumor smaller than 3cm in greatest diameter distal to the origin of a lobar bronchus, with (T1 N1 M0) or without (T1 N0 M0) metastasis to ipsilateral regional nodes or a larger tumor distal to the carina that invades the visceral pleura but does not have nodal or distant metastasis (T2 N0 M0).

Lung Cancer Stage II

A tumor of any size, distal to the carina that invades the visceral pleura and extends only to the nodes in the ipsilateral hilar region (T2 N1 M0).

Lung Cancer Stage III

Any tumor that is more extensive locally or shows metastasis beyond the ipsilateral lymph nodes(e.g., contra-lateral nodes, mediastinum, liver and brain).

In AJC system the cancers are divided into stages 0 to IV, incorporating the size of primary lesions as well as the presence of nodal spread of distant metastasis.

However, that the staging of neoplastic disease in the patients has incorporated greater importance in selection of the best form of therapy for the patient and in multi-center treatment comparisons and as compared with grading, staging has proved to be of greater clinical value.

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