The study of etiology of lung cancer will help us understand the important factors responsible for causing this disease. Increase in the level of carcinogens in the environment is one of the main reasons behind rise in the cases of lung cancer.
The medical condition of lung cancer can be simply described as one in which uncontrolled cell growth takes place in the lungs. This cancerous growth may not remain limited to the lung region. When the lung cancer spreads to other parts of the body, the condition is referred to as metastasis. Transformation of epithelial cells into malignant tumors is observed in lung cancer. These malignant tumors which have undergone transformation are referred to as carcinomas. The cells other than epithelial cells can also turn into carcinomas. However, they should have the specific molecular characteristics similar to that of the epithelial cells. Here is more information on lung cancer and specifically the etiology of this disease.
Lung Cancer Etiology
Etiology of a particular disease is the study of the origin and cause of a disease. Understanding the causal factors of a disease proves to be crucial in determining the treatment. Here are some useful details pertaining to etiology of lung cancer.
Tobacco Smoking
Out of the total number of cancer-related deaths, 90% take place due to smoking; it means that more deaths are caused by lung cancer than all other cancers put together. The smoke of tobacco contains over 60 carcinogens and is one of the major factors in causing lung cancer. Exposure to carcinogens result in changes in the DNA (mutations) of the cells of bronchi; mutations change the genetic make up of cells and trigger their uncontrolled growth. These changes are responsible for causing cancerous growth in lungs.
Examples of carcinogens present in cigarette smoke are as follows: benzopyrene, nitrosamine, radioisotopes, etc. Those women who smoke and also take hormone therapy are at an increased risk of suffering from lung cancer. Chances of development of lung cancer increase with smoking. The converse of this statement is also true. It means that lowering the rate at which one smokes can decrease the chances of development of cancer. Eighty-six percent smokers diagnosed with lung cancer die within a period of 5 years.
Environmental Factors
Important facts pertaining to environmental factors or external agents associated with lung cancer are presented below. Radon gas, particulate matter, asbestos, etc. are the different environmental factors associated with cancer. The element called asbestos is one of the important causes of lung cancer. The habit of smoking increases the dangers resulting from asbestos. The combined effect of asbestos and smoking allows the cancer to grow at a faster rate. About 2-3% lung cancer deaths which take place in the United Kingdom are due to asbestos exposure. In the United States of America, exposure to asbestos is the reason behind 3,400 to 8,500 lung cancer cases. Another symptom which develops along with lung cancer is asbestosis.
The American Cancer Society deems particulate matter present in air as an important cause of lung cancer. According to the research carried out to understand the relation between lung cancer and particulate matter, it has been observed that 1% rise in particulate matter (in air) increases the risk of lung cancer by about 14%. Smoking contributes greatly to the development of lung cancer, which is why it is difficult to carry out a separate study about the contribution of particulate matter in lung cancer.
Another factor that poses a risk to lung cancer is radon gas. Exposure to radon gas is the second most important cause of lung cancer after smoking. Degeneration of radioactive radium results in the creation of radon gas. Mutations brought about by radon gas are responsible for causing lung cancer. This gas enters the body by means of inhalation. The radon gas is odorless, invisible and also tasteless.
Biological Agents
Viruses are amongst the important causes of lung cancer. These organisms alter the way in which the normal functioning of cells takes place. There are few viruses responsible for causing lung cancer in human beings and animals. Examples of these viruses are as follows: simian virus 40 (SV40), JC virus, cytomegalovirus, BK virus and human papillomavirus. These viruses are responsible for altering the functioning of cell cycle. The process of apoptosis results in the death of cells. This process is affected by viruses and cause uncontrolled cell growth. The measles virus is also one of the causal factors of lung cancer. This virus doesn’t actually cause cancer by itself, but acts as a catalyst in the process of causing lung cancer; it modifies the effect of other carcinogens and thereby plays an indirect role in this process.
Symptoms and Treatment of Lung Cancer
Coughing and shortness of breath are the commonly observed symptoms of lung cancer. Other symptoms associated with this disease are as follows: wheezing, hemoptysis, dysphonia, clubbing of the fingernails, fatigue, weight loss, dysphagia and chest pain. In the dysphagia, one experiences difficulty in swallowing. Dysphonia is a condition in which the voice becomes hoarse while in hemoptysis, the patient coughs up blood. The degree to which lung cancer has spread in the body determines the treatment measures for this disease. Treatments that are commonly used for lung cancer include chemotherapy, surgery, palliative care and radiation therapy.
These are the important causes which increase the chances of lung cancer. Smoking is the most important causal factor of this serious illness. Therefore quitting smoking and eliminating exposure to tobacco smoke are important for preventing the risks of lung cancer.
