Lung cancer is of two major types, the Non-Small Cell Lung Cancer (NSCLC) and the Small Cell Lung Cancer (SCLC). The NSCLC is more common making up about 80-85% of all lung cancers while the SCLC accounts for about 15-20%.
Treatment and prognosis of the cancer depends on the extent to which the disease has spread; this is also referred to as the stage of the cancer. The chance of success in treatment largely depends on the stage at which the cancer was diagnosed, with early stages showing a better prognosis. Diagnosis of lung cancer is usually done in the later stages as lung cancer doesn’t produce very obvious symptoms.
The NSCLC can be divided into 4 different stages while the SCLC occurs in two distinct stages. The four stages of non-small cell lung cancer include the following:
Stage 1 – The cancer is confined to the lung.
Stage 2 – The cancer is found in the lung as well as nearby lymph nodes
Stage 3 – Cancer is found in the lung as well as in the lymph nodes in the middle of the chest.
Stage 3A – The cancer in the lung and lymph nodes is found on the same side of the chest.
Stage 3B – The cancer has spread from lung to lymph nodes on opposite side of the chest or above the collar bone.
Stage 4 – The cancer has spread to both the lungs and to other parts of the body.
The small-cell lung cancer (SCLC) has two main stages:
Limited stage – The cancer can be found confined to one lung and its associated lymph nodes on the same side of the chest.
Extensive stage – The cancer has spread beyond the initial focus to the opposite lung and lymph nodes or to the bone marrow or distant organs. Majority of SCLC patients are already in the extensive stage when diagnosed.
Dividing the cancer into various stages helps in evaluating the treatment regime to be used for that particular case as well as making an educated prognosis. Lower stage cancer masses have better prognosis than higher stage masses. Surgery cannot remove the cancerous cells completely; rounds of chemotherapy in combination with radiotherapy would be needed for complete recovery. If the patient is in a fairly healthy state, chances of recovery are enhanced.
At the clinical level, accurate staging of lung cancer is based on the results of physical exams, biopsies, blood tests, chest X-rays and CT and PET scans, etc. Scans provide a very good idea of the size of the mass as well as the presence of metastases.
In cases where surgery was performed, a better pathologic evaluation can be made to add to the clinical picture. Pathologic stage evaluations are more likely to be accurate than the clinical stage as imaging techniques might not always throw up the full extent of the spread of the disease.