Four Different Stages of Lung Cancer

There are four different stages of lung cancer depending on the spread of tumors inside the body. Like every other form of cancer, tests and scans have to be performed in order to decide the stage of illness. It helps the doctor for prognosis and potential treatment of the patient. Staging involves evaluation of spread of cancer within the lungs and presence or absence of metastases in the lymph nodes or in other organs. All the four different stages of lung cancer include information on the size of the tumor and tells whether the cancer is only in the lymph nodes or has spread beyond it.

Lung cancer is a result of excessive growth of cells in the tissues of lungs, and is responsible for 1.3 billion deaths in the world annually. These uncontrolled cells get accumulated forming a tumor, which is very different from the neighboring cells within the periphery. These tumors can be fatal as they take oxygen and nutrients from healthy cells. In the US, lung cancer has already surpassed the number of deaths by breast and prostate cancer taken together. The major causes of lung cancer are smoking, radon gas and prolonged contact with asbestos. It's prominent symptoms are coughing up blood, shortness of breath, pain the chest, back or arms and repeated episodes of pneumonia or bronchitis. Cancer in the right lung is slightly more common than in the left. There are basically two forms of lung cancer:

• Small Cell Lung Cancer (SCLC): This is the less common form of lung cancer and spreads throughout the body at an alarming rate. The prime reason for this kind of lung cancer is smoking.
• Non-Small Cell Lung Cancer (NSCLC): This is common amongst the lung cancer patients and includes several subtypes of tumors namely squamous cell lung carcinoma, adenocarcinoma and large cell lung carcinoma.

To determine the stage of lung cancer in a patient accurately, X-rays, CT scans, Lab tests, MRI scans and bone scans are used by doctors. Positive lab tests are due to the presence of metastases in bone or liver, and with the help of radiological procedures, size of a cancer and possible spread to other organs can be known. Following are the different stages of lung cancer:

1. Stage I
   In the first stage, the cancer is localized and do not affect the lymph nodes. This is the stage where the patient can be easily cured with the hep of surgery, but only 15% of the patients of lung cancer are diagnosed earlier. The cancer invades the underlying lung tissue and depending upon the size of tumor, it can be further divided into two parts:
• Stage I A: The tumor is small in this stage (usually 3 cm or less).
• Stage I B: The tumor is larger as compared to Stage IA and sometimes may lead to partial collapse of the affected lung.
2. Stage II
   In the second stage, the cancer has spread to the neighboring lymph nodes or further invades the chest wall. In some cases, it also spreads to lining of the lungs, diaphragm, or the outer lining that surrounds the heart. Depending on tumor's size and spread, Stage II can be divided further into two sub-stages:
• Stage II A: In this case, although the cancer is small, it has spread to the lymph nodes near to the affected lung.
• Stage II B: The tumor size is larger and the cancer may or may not have reached the lymph nodes. If the lymph nodes are not affected, cancer grows inside the chest wall, oesophagus or outer lining of heart.
3. Stage III
   In stage III, the cancer spreads in the lymph nodes covering the area of the chest between the heart and lungs, sometimes affecting the blood vessels too. It can also be divided into two sub-stages:
• Stage III A: The cancer spreads to lymph nodes on the same side of the chest where it initially stated. It may also have spread to the chest wall, pleura or middle of the chest.
• Stage III B: The cancer in this stage spreads to nodes on the other side of the chest, and the tumor could have grown in the heart, windpipe or oesophagus. In the case of non small cell lung cancer, pleural effusion, which is a fluid between the membranes covering the outside lungs is checked by scans. If the cancer cells are found in the fluid, it is considered to be at stage IIIB. Stage IIIB is usually treated with chemotherapy only or chemotherapy and radiation.
4. Stage IV
   Stage IV means the cancer has spread beyond the lungs, to other parts of the body. Surgery cannot be considered as a potential treatment in this case, and the patient is left with the option of chemotherapy and radiation only. The survival rate for IV stage lung cancer is less than 10%, the median survival time being 8 months. Apart from the normal symptoms of lung cancer, difficulty in swallowing, headaches and vision changes are some other problems faced by the patient in IV stage.

Survival reports differ by significant percentage as shown by reports. According to the two different reports by Wu and Naruke, the 5-year cumulative survival rate was 68.5% to 88.0% for patients in stage I A, 46.9% to 53.9% in stage I B, 33.5% to 46.9% in stage II, 14.7% to 26.1% in stage III A, 5.5% to 9.0% in stage III B and 7.0% to 11.2% in stage IV, in the year 1999. It can be seen easily that the mortality rate goes high as the patient advances through the four different stages of lung cancer. So it is always advisable not to neglect the common symptoms, and consult a doctor before the stage of lung cancer advances.