My project is about lung cancer, which falls under the science branch of oncology. Lung cancer is the uncontrolled growth of abnormal cells in the lung. The uncontrolled reproduction of cells results in the formation of tumors that can block or compress airways and displace or damage normal lung tissue. This can make the lung stop functioning as it should. Most lung cancers start in the lining of the bronchi, or in glands below the lining of the bronchi, frequently in the periphery of the lungs.
When they are exposed to irritants or carcinogens, the epithelium continually replaces itself until the cells develop chromosomal changes and become altered in size, shape, and organization. These dysplastic cells don’t function well as protectors, so underlying tissue gets exposed to irritant and carcinogens. Eventually, these dysplastic cells turn into a tumor and start invading deeper tissue. This would make most lung cancers malignant, which means that they invade and destroy the healthy tissues around them and can spread throughout the body. The tumors can spread to nearby lymph nodes or through the bloodstream to other organs.
This process is called metastasis. When lung cancer spreads, the tumor in the lung is called the primary tumor, and the tumors in other parts of the body are called secondary tumors or metastatic tumors. There are two main types of lung cancer: small cell lung cancer and non-small cell lung cancer. Small cell lung cancer, which is also called oat cell cancer, is less common than non-small cell lung cancer. This type of lung cancer usually starts in one of the larger breathing tubes, grows fairly rapidly, and is likely to be large by the time of diagnosis.
Small cell lung cancer accounts for about 20 percent of all lung cancers. Non-small cell lung cancer is much more common, and usually grows and spreads more slowly than small cell lung cancer. There are 3 types of non-small cell lung cancer which are Squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. Squamous cell carcinoma starts in one of the larger breathing tubes and grows relatively slowly. Adenocarcinoma starts growing near the outside surface of the lung and may vary in both size and growth rate. Some slowly growing adenocarcinomas are called bronchoalveolar cancer.
Large cell carcinoma starts near the surface of the lung, grows rapidly, and is usually large when diagnosed. Lung cancer can cause many breathing and heart problems. The condition of pleural effusion, which is the buildup of fluid between the outer lining of the lungs and the chest wall is common. This causes infection, inflammation, heart failure, or pancreatitis. A collapsed lung, known as pneumothorax, results from a buildup of air in the space between the lung and the chest wall. This prevents the lung from expanding properly when the person tries to breathe in, causing shortness of breath and chest pain.
Bronchial obstruction, which is the blockage of airway, and recurrent infections, such as pneumonia, are also causes from lung cancer. The main cause for lung cancer is cigarette smoking. Tobacco smoke contains over 4000 chemicals, 60 of which are known to be carcinogenic, or cancer-causing. The likelihood that a smoker will develop lung cancer is affected by how early they start smoking, how long they have smoked, and how many cigarettes they smoke per day. It is also affected by how deeply they inhale the smoke. Secondhand smoke is also a cause for lung cancer.
People who inhale secondhand smoke have a 24% increase in risk for developing lung cancer and there are an estimated 3,000 lung cancer deaths occur each year in the U. S. that are attributable to passive smoking. Other causes for lung cancer are asbestos fibers and radon gas. The symptoms for lung cancer are listed here, and they consist of: persistent cough, shortness of breath, chest pain, wheezing, coughing up blood, a hoarse voice, chest, shoulder, or back pain that does not go away, swelling in face and neck, difficulty swallowing, weight loss & loss of appetite, fatigue/weakness, and respiratory infections such as pneumonia.
The survival of lung cancer is usually based on the 5-year survival rate. The 5-year survival rate is the percentage of people who are still alive 5 years after being diagnosed. The average survival rate of lung cancer is 16% of people still being alive 5 years after being diagnosed. Fortunately, there are treatments for having lung cancer. Surgery is an option, which involves partial lung removal or total lung removal. Radiation may reduce the tumor’s bulk, which will allow surgical resection and improvement of the patient’s response.
Chemotherapy causes dramatic, but temporary, responses in patients with small-cell lung cancer. The other types, however, are fairly resistant to it. If you smoke and have lung cancer, quitting smoking will make your treatment more effective and may help you live longer. Interesting thing I learned is that in most cases, lung cancer is only diagnosed when it is already in an advanced stage, making it the 3rd largest killer in the United States.