Understanding the Stages of Lung Cancer

Staging is the process used to determine how far the lung cancer has spread. The level or stage that is determined as the result of the staging process provides guidance to the health care team in determining lung cancer treatment. The doctors will also consider the characteristics of the lung cancer disease and overall health status of the patient.

Types of Staging.

There are two types of staging that may be used to determine the spread of the lung cancer: clinical and pathological.

Clinical staging is noninvasive and uses physical exams; imaging studies, such as CAT and PET scans and MRIs; and laboratory tests to determine the spread of the lung cancer.

Pathological staging is based both on clinical staging and on results obtained through biopsies and surgery. It is considered more accurate than clinical staging. However, a lung cancer patient with clear presurgical evidence of widespread disease usually will not be staged via surgery.

Lung Cancer Staging

There are two types of lung cancer: Small Cell Lung Cancer also called Small Cell Carcinoma, and Non-small Lung Cancer, also called Non-small Cell Carcinoma. Most people with lung cancer have Non-small Cell Carcinoma. These cancers are staged differently.

Small Cell Lung Cancer is divided into 2 stages: Limited Small Cell Lung Cancer and Extensive Small Cell Lung Cancer. With a stage of Limited Small Cell Lung Cancer the cancer has remained within the lung where it started or the lymph nodes and tissues between that lung and the non affected lung. The lung tissue and has not moved to other parts of the body. In Extensive Small Cell Lung Cancer the cancer has invaded other tissues outside the lung where it started.

Non-small Cell Lung Cancer is staged with a system used for other solid tumors such as breast and prostate cancer. This system is called the T-N-M Staging System.

The T stands for tumor, and T categories are based on tumor size, its spread and location within the lungs, and spread to nearby tissues.

The N stands for node, and N categories are based on whether the cancer has spread to which, if any, lymph nodes near the lung.

M stands for metastasis, and this category is determined by whether the cancer has spread to any distant tissues and organs.

There are several stages of non-small cell lung cancer. The severity of the cancer in terms of spread and metastasis increased as the Stage number goes up. As the Stage increases the complexity of the tumor increases as it grows and invades different parts of the chest cavity and spreads to more distant areas of the body.

This is a cancer in which there is a stage where no cancer cells can be found in the lungs but cancer cells are found in mucous that is spit up by the patient or where the tumor is too small to be checked. This stage is called the Occult Stage.

The other stages are related to the description of the tumor in relation to its size and spread any distant metastases. As the stage increases from 0 to IV, the complexity and spread of the tumor increases.

Stage 0

In Stage 0, cancer is found only in the layer of cells that line the air passages.

There is no spread to other lung tissues, to any lymph nodes, or to any distant

sites. Stage 0 is also called carcinoma in situ.

Stage I

Stage I has two possibilities: Stage IA and Stage IB. The tumor is may be larger or smaller than 3 centimeters and is confined to the lung. There is no spread of the cancer to any distant sites. However in Stage IB the cancer has spread to the lymph nodes on the same side as the cancerous lung.

Stage II

In Stage II, there are also two sub stages: Stage IIA and Stage II B. There is no spread of the cancer to the lymph nodes but the cancer has spread beyond the lung and into other areas around the lung including the chest wall, the diaphragm and/or the heart membranes. If the Stage is IIB, there may be a collapsed lung due to the spread of the cancer and pneumonia is more likely.

Stage III

Stage III is perhaps the most complicated with two sub stages, Stage IIIA and Stage IIIB describing the spread of the tumor within the lung and to the areas around the lung. There may or may not be lymph node involvement and there no spread to distant sites.

Stage IV

In Stage IV, the tumor may have may have spread locally to the chest wall the heart, trachea and esophagus and/or the backbone. However, there is also evidence of spread of the cancer to one or more distant sites, including other sites within the lungs, distant lymph nodes and other organs or tissue such as liver, bones or
brain.

References

http://www.cancer.gov/cancertopics/pdq/treatment/non-small-cell-lung/patient

http://www.cancer.gov/cancertopics/pdq/treatment/small-cell-lung/patient