The standard classification protocol for all types of cancer is a sophisticated and complicated analytical tool that requires information on the tumor, the lymph nodes, and any evidence of metastases. The end result is a four-stage format that provides an analysis of the degree to which the cancer has advanced and the appropriate treatment. There is an interesting parallel for small cell lung cancer (SCLC) and mesothelioma, because both are linked to asbestos exposure and smoking, mesothelioma most commonly develops in the chest cavity, yet there are different staging systems for the two types of malignancy.
Small cell lung cancer (SCLC) has some unusual characteristics that have led to a simplified two-stage classification scheme. It is a very aggressive, fast moving form of lung cancer that is rarely diagnosed in its early stages. In many cases there will be no overt symptoms until well after the cancer has metastasized to distant parts of the body. In addition, SCLC is highly responsive to treatment with chemotherapy and radiation. As a result surgery is rarely performed with SCLC because the diagnosis has occurred at the point where surgery cannot remove all or even most of the malignant tissue. The upshot is a disease for which the treatment is the same regardless of how advanced it is. The only two stages needed for diagnostic purposes with SCLC are limited, and extensive. One is for the earlier stages of the disease, the other for cases where there has been significant metastasis.
Limited Small Cell Lung Cancer
SCLC almost always develops in the bronchi, the tubes that connect the two lungs with the windpipe. The definition of limited small cell lung cancer states that the disease remains on one side of the body – that is, in just one lung – and that it has spread only to lymph nodes in the near vicinity. Generally speaking, all of the stage 1, 2, and 3 definitions of lung cancer would fall into the limited category for SCLC. The only definition for early small cell lung cancer includes conditions that would be categorized as fairly advanced in non-small cell lung cancer stages.
Stage 3 Small Cell Lung Cancer Definitions
There are several possible scenarios that lead to a stage 3 classification. For stage 3A one of the following is true: the tumor is in only one lobe of the lung and in the adjacent lymph nodes; the tumor has grown into the chest wall; there are two or more tumor modules in the same lung; the tumor is large enough to block the airway and cause a collapsed lung. Stage 3B presents one of these scenarios: the tumor is in one lung but has spread to lymph nodes on both sides of the chest cavity; the tumor has grown into the space between the lungs or the esophagus or the trachea or the spine; two or more tumor nodules are present in different lobes of the same lung.