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| Stage 4 lung cancer |
Why is it important to know the stage of the disease? Well, staging basically indicates how much the cancer has spread, both within the lung and in other parts of the body. As you can imagine, this information is critically important in deciding on the kind of treatment to adopt. This is why doctors look at staging. Stage 4 lung cancer is a very advanced phase of the disease.
There are different kinds of staging systems. Many doctors use a very detailed one called the TNM staging system. This takes into account the size of the cancerous tumor, the degree of spread to the lymph nodes as well as to other parts of the body.
Broadly speaking, as far as non small cell lung cancer (NSCLC) is concerned, there are four stages involved, numbered from 1 to 4. Stage 1 NSCLC is when the cancer is entirely localized in a small area of the lung. This is the most treatable stage of the cancer and survival rates are relatively high when compared to the other three stages.
This stage is divided into two sub stages - 1A and 1B. Stage 1A refers to cases where the tumor is less than 3 cms in size. Stage 1B includes cancers larger than 3 cms (but still relatively small), cancers that have caused a partial collapse of the lung and those that have affected the inner lung covering.
Stage 2 lung cancer likewise has two phases - 2A and 2B. The former means that the cancer has affected lymph nodes adjoining the lungs. In stage 2B, the cancer is larger than 3 cms across and has affected the lymph nodes. It can also mean that the cancer has not affected the lymph nodes but has affected the diaphragm, the lung's outer covering or the chest wall itself.
Stage 3A in non small cell lung cancer can mean that the cancer is localized on one side of the chest but has affected the lymph nodes that are located further away from the lung. This stage also covers a condition where only the lymph nodes nearest the lung are affected but the chest wall or the middle portion of the chest have been afflicted.
Stage 3B can mean a number of things. There is a fluid collection around the lung - if this contains cancerous cells, it may be classified as stage 3B. Alternatively, there may be two or more cancer tumors in the affected lung lobe. It could also mean that the cancer has spread to points above the collarbone. Or that it has affected another major part of the chest like the windpipe, a large blood vessel, etc.
Stage 4 lung cancer is the final stage involved. Here, the cancer could have affected another body organ like the liver, the bones, etc. Or it could have struck another lobe of the lung. It has progressed beyond a single localized tumor.
Both non small cell lung cancer and small cell lung cancer can, in theory, be classified into the four stages above. However, small cell lung cancer spread fast and early. So it is usually divided into just two stages instead of four as above.
It is best to diagnose the disease well before it progresses to become stage 4 lung cancer. Early detection is the key to successful treatment.