Once a diagnosis of lung cancer has been made, the doctor will attempt to determine the stage the lung cancer is at. The staging system is somewhat like a measurement system, with the numbers indicating: whether the cancerous tumors are localized or whether the tumors have spread to other parts of the body; the tumor’s size; and whether or not the tumors have spread to the lymph nodes. There are four main stages of lung cancer (Stages 1 – 4) and identification of one of the stages is what helps doctors prescribe an appropriate treatment method. Different Cancer, Different Stages of Lung Cancer The staging system is a bit more complicated than simply assigning a number. First of all, the stage numbering system differs slightly depending on whether the lung cancer has been diagnosed as small cell lung cancer or non-small cell lung cancer. Non-Small Cell Lung Cancer Non-small cell lung cancer is the more common form and it progresses more slowly than the other type. Non-small lung cancer can be broken down into 4 stages. Stage 1 means that the tumor is local; it has not spread to the lymph nodes. Adding the letter A or B to the stage 1 classification indicates the size of the tumor (“A” means it is less than 3 cm across) and whether it’s larger and growing in a sensitive area (“B”). Stage 2 means the tumor has spread into lymph nodes or the chest wall. Again, an “A” and “B” designation determines the size and the location of the tumor. Stage 3 is more complicated and can mean several things. For example, it can indicate that the tumor has spread, but it’s still only affecting one side of the lung, or that tumors have spread to other nearby body parts such as the chest wall, or that fluid is collecting in the lungs. Stage 4 is of course the worst stage and means that cancerous tumors have spread into a whole other part of the body like the pelvis or liver. Small-Cell Cancer In cases of small-cell cancer, there are two stages of lung cancer – Stage 1 and Stage 2. These stages are used to designate whether the cancerous cells are limited in number or whether there exists an extensive amount that have invaded the chest and other parts of the body. When they’re limited in number, patients have a good chance of receiving effective treatment and possibly even resuming a near normal life. An extensive amount however, means treatment options are very limited. The Staging Challenge Although the stages of lung cancer seem well-defined, categorizing a person’s cancer into one of these stages is often challenging. Each case of cancer involves so many different factors and the combination of factors can be interpreted in many different ways by different doctors. Proper diagnosis and classification takes time and may take several rounds of testing. CT scans, MRIs, blood tests, bone scans and even testing the pleural effusion (if present) may all be needed.