The Significance of Lung Cancer Staging
A system of staging is used to classify different types of cancer. Doctors use lung cancer staging to identify the progression of the disease. Treatment options and patient prognosis are affected by what stage the disease is diagnosed in.
A physical examination, blood test and diagnostic imaging are used to find the source of the lung cancer symptoms. Testing will discover any metastasis to other body parts, tumor size and location. A CAT scan, MRI or PET scan is used to find identify the stage.
Non Small Cell cancers of the lung (NSCLC) use the ‘TNM’ classification system. ‘T’ represents tumor, ‘M’ is the presence and degree of metastasis and ‘N’ indicates lymph node. Each letter is assigned a number, from 0-4, to indicate size and/or severity.
A T1 or T2 tumor represents a size of less than 3 centimeters or larger that does not extend into the chest area. T3 and T4 designations are tumors in the chest cavity or considered inoperable, respectively.
Lymph nodes are assigned a rating of 0-3. A rating of 0 indicates they are unaffected. N1 identifies tumors with lymph node activity in the lungs. N2 is for tumors in the chest cavity or respiratory passages and N3 involves the neck area and above.
Metastasis indicates the disease has spread. A 0 rating means the cancer has not metastasized, while M1 means it has. In general, a higher number is synonymous with a shorter life expectancy.
Once this data has been attained, the cancer is divided into one of four stages. Stage 1 and 1B are early stages with no metastasis and no involvement of the lymph nodes. At this stage the cancer is generally operable. Stage 2 and 2B are assigned when the lymph nodes are affected. Prognosis is reduced, but the tumor is still operable.
Stage 3A and 3B are for advanced lymph node involvement. At this stage, other areas of the lungs and chest area may also be affected. Stage 4 is considered inoperable. Treatment is limited to comforting the patient and prolonging their life. Prognosis at this stage is less than two percent.