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Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.
Types of cancer can be grouped into broader categories. The main categories of cancer include:
Carcinoma - cancer that begins in the skin or in tissues that line or cover internal organs.
Sarcoma - cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Leukemia - cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
Lymphoma and myeloma - cancers that begin in the cells of the immune system.
Central nervous system cancers - cancers that begin in the tissues of the brain and spinal cord.
This essay will focus on lung cancer. And I will introduce two main types of lung cancer, non-small cell lung cancer and small cell lung cancer.
How cancer starts? Cancer starts when cells in a part of the body start to grow out of control. Cancer cell growth is different from normal cell growth. Instead of dying, cancer cells continue to grow and form new, abnormal cells. Cancer cells can also invade other tissues, something that normal cells cannot do. Growing out of control and invading other tissues are what makes a cell a cancer cell.
Cells become cancer cells because of damage to DNA. DNA is in every cell and directs all its actions. In a normal cell, when DNA gets damaged the cell either repairs the damage or the cell dies. In cancer cells, the damaged DNA is not repaired, but the cell doesn't die like it should. Instead, this cell goes on making new cells that the body does not need. These new cells will all have the same damaged DNA as the first cell does.
People can inherit damaged DNA, but most DNA damage is caused by mistakes that happen while the normal cell is reproducing or by something in our environment.
Lung cancer is a disease which consists of uncontrolled cell growth in tissues of the lung. This growth may lead to metastasis, which is the invasion of adjacent tissue and infiltration beyond the lungs. The vast majority of primary lung cancers are carcinomas of the lung, derived from epithelial cells. The most common symptoms are shortness of breath, coughing and weight loss.
In lung cancer, there are two main types of lung cancer, non-small cell lung cancer and small cell lung cancer.
Non-small cell lung cancer (NSCLC) accounts for about 80% of lung cancers. There are different types of NSCLC, including Squamous cell carcinoma, Adenocarcinoma, Bronchioalveolar carcinoma and Large-cell undifferentiated carcinoma.
Squamous cell carcinoma are also called epidermoid carcinoma. This is the most common type of NSCLC. It forms in the lining of the bronchial tubes and is the most common type of lung cancer in men.
Adenocarcinoma. This cancer is found in the glands of the lungs that produce mucus. This is the most common type of lung cancer in women and also among people who have not smoked.
Bronchioalveolar carcinoma. This is a rare subset of adenocarcinoma. It forms near the lungs' air sacs. Recent clinical research has shown that this type of cancer responds more effectively to the newer targeted therapies.
Large-cell undifferentiated carcinoma. This cancer forms near the surface, or outer edges, of the lungs. It can grow rapidly.
Small cell lung cancer (SCLC) accounts for about 20% of all lung cancers. Although the cells are small, they multiply quickly and form large tumors that can spread throughout the body. Smoking is almost always the cause of SCLC.
Nowadays, we can test the lung cancer with X-ray inspection, computed tomography, Cytology test, Bronchoscopy and Mediastinoscopy.
X-ray inspection can see the cancer size and location. Computed tomography can see the hidden areas of lung disease.
Cytology test are test the patient's sputum. It can be found off the cells, and may determine the classification of cancer.
Bronchoscopy can be directly observed through the bronchoscope lumen endobronchial and pathological changes, and have access to specimens for cytology or histological examination.
Mediastinoscopy are used to violations identified the central lung cancer mediastinal range.
Lung cancer is not easy to found. We always found the lung cancer in the later period. The cancer cell will spread to organs and tissues outside the lung. The doctor just can help the patients reduce pain and make their life longer. Nowadays, we have four methods to cure the patients.
First, Surgical procedure, it means complete resection of primary lung cancer lesion and local lymph and keep the healthy lung tissue.
Secondly, Radiation Therapy, it means local anti-cancer lesions.
Then the Chemotherapy, anticancer drugs inhibit cancer cell growth, reproduction and kill cancer cells.
Finally the target therapy, the major drug targets for cancer and abnormal metabolism of some unique ways to kill cancer cells, so that different cancers to use a different drug targets
Many of research shown us smoking and lung cancer have a close relationship. Smoke contains benzopyrene and other carcinogens. If we have smoking hobbies for a long term, we will easy to get squamous cell carcinoma and undifferentiated small cell carcinoma.
This figure shows that many people smoking and the mortality rate increase.
In the working areas, if it had asbestos, coal tar, tobacco or radioactive substances such as uranium, radon, radium, it can induce lung cancer.
Radon is a colorless and odorless gas generated by the breakdown of radioactive radium, which in turn is the decay product of uranium, found in the Earth's crust.
The radiation decay products ionize genetic material, causing mutations that sometimes turn cancerous. Radon exposure is the second major cause of lung cancer in the general population, after smoking with the risk increasing by 8% to 16% for every 100 Bq/m^3 increase in radon.
We know that cancer is so danger, so we need to do some actions to reduce the opportunities on causing cancer. Not smoking is one of the ways to prevent lung cancer, because at least fifty kinds of cigarettes or more carcinogens. In addition, air pollution, radioactive such as uranium, radon and mineral such as asbestos, tar for metals such as nickel, arsenic and other carcinogens in environmental work, should take protective measures to reduce staff by as much as possible Radiation. While chronic lung disease, family history of lung cancer will increase the risk of cancer.
Lung cancer is the major cancer in Hong Kong. Lung cancer is a disease which consists of uncontrolled cell growth in tissues of the lung. Lung cancer is the most malignant epithelial cells of lung cancer, caused by epithelial cell lesions. The main types of lung cancer are small cell lung carcinoma and non-small cell lung carcinoma. Although today's medical advances, but in terms of lung cancer patients, it is not enough. Smoking is a big problem and it will make easy to get lung cancer. Avoid smoking is the best.