Lung cancer is caused by uncontrolled rapid growth of cells in tissues. This type of cancer is most common and results in more than a million deaths every year. This form of cancer is indicated by weight loss or coughing up blood or regularly going out of breath. It can be noticed on chest radio graph also called CT Scan. The treatment that one gets depends on the stage that one is in. Treatment of cancer include surgery, chemotherapy and radiotherapy.
Lung cancer may be the most tragic cancer because in most cases, it might have been prevented, 87% of lung cancer cases are caused by smoking. Lung cancer has long been the most common cause of cancer death in men and since 1987 it has also become the most common cause of cancer death in women. Lung cancer is the second most commonly occurring form of cancer in most western countries and although the lung cancer incidence is less common in developing countries, the rapid increase in the popularity of smoking will see the number of lung cancer sufferers in those countries quickly catch up with the western world.
Lung cancers can arise in any part of the lung, and 90%-95% of cancers of the lung are thought to arise from the epithelial, or lining cells of the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic carcinomas or bronchogenic cancers.
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Causes, Symptoms and Treatment of Lung Cancer
The most common type of lung cancers are epidermoid carcinoma, small cell carcinoma, adenocarcinoma and large cell carcinoma.
Most experts agree that lung cancer is attributable to inhalation of carcinogenic pollutants by a susceptible host. Who is most susceptible? Any smoker over the age of 40, especially if they began smoking before the age of 15, have smoked 20 or more for 20 years, or worked with or near asbestos. Two other factors also increase susceptibility: exposure to carcinogenic industrial and air pollutants (asbestos, uranium, arsenic, nickel, iron oxides, chromium, radio active dust, and coal dust.) and familial susceptibility.
Causes of Lung Cancer
The three main causes of cancer are: carcinogens (which is found in tobacco ), viral infection and ionizing radiation. If exposed, it causes changes to DNA in tissue lining the bronchi of the lungs. With more and more tissues getting damaged, cancer develops.
1. Smoking cause Lung Cancer
Smoking is the main cause of cancer. In one cigarette, there are 60 different known types of carcinogens like radioisotopes and nitrosamine. Smoking is believed to cause 80% of these type of cases. The risk is generally less in non -smokers. The time that a person smokes proportionately increases the chances of this cancer. There has been cases that if a person stops smoking, the damaged cells gradually gets repaired. In non-smokers, passive smoking is the main causes of lung-cancer. Passive smoking is one inhaled from another person smoking.
2. Radon Gas cause Lung Cancer
The gas produced from breakdown of radium. This gas is colourless and odorless. Exposure to radiation ionize the genetic material, causing mutations that sometimes turn cancerous. Exposure to radon gas is the second major cause of lung-cancer after smoking.
3. Asbestos cause Lung Cancer
Asbestos is responsible for causing a number of cancer, one among them is lung cancer. In UK, asbestos accounts for 2 to 3% of the total cases of this cancer.
4. Virus cause Lung Cancer
Viruses are responsible for causing lung-cancer in animals. And research has shown of similar potential in humans.
5. Particulate Matter cause Lung Cancer
Particulate matter has a direct link to lung cancer cases. The size and quantity of particles in air determines the risk of getting lung-cancer. If concentration of particles increases beyond 1%, then the chances of getting this increases by 14%.
Pathogenesis of Lung Cancer
Just like may other cancer forms, lung cancer is started by activation of ocnogenes or inactivation of tumor suppressing genes. Ocnogenes are those genes that make people more vulnerable to cancer. Ocnogenes are produced from proto-ocnogenes, when the latter is exposed to particular carcinogens. In k-ras proto-oncogene, mutations takes place which are responsible for 10 to 30% of lung adenocarcinomas. Tumor invasion, angiogenesis, apoptosis, cell profileration are regulated by the Epidermal growth factor receptor. Mutations and amplification of EGFR are common in non -small cell lung cancer. The basis for treatment with EGFR-inhibitors are also provided by Mutation and amplification of EGFR. Chromosomal damage can lead to loss of heterozygosity which can result in inactivation of tumor suppressor genes. Damage to four of these chromosomes:3p, 5q, 13 q and 17 p are common in small cell lung-carcinoma. The p53, which is a tumor suppressor gene, located on chromosome 17p is affected in most of the cases. c-MET, NKX2-1, LKB1, PIK3A and BRAF are also mutated or amplified. Various genetic polymorphisms are supplementary to this cancer. Some of them include polymorphisms in genes coding for interleukin-1, cytochrome p450, apoptosis promoters such as caspase-8, and XRCC1, which is DNA repair molecule. People having these polymorphisms are more likely to develop lung cancer on being exposed to carcinogens. The research has revealed that MDM2 309G allele is a low-penetrant risk factor for developing this in Asians.
Signs and Symtoms of Lung Cancer
Because early lung cancer usually produces no symptoms, the disease is often in an advanced stage when first diagnosed. Late stage signs are: with epidermoid and small cell carcinoma; smokers cough, hoarseness, wheezing, dyspnea, hemoptysis and chest pain. With adenocarcinoma and large cell carcinoma; fever, weakness, weight loss, anorexia and shoulder pain. In addition, hormone production which regulates various body functions may also be affected.
Diagnosis of Lung Cancer
Firm diagnosis requires chest x rays, sputum cytology, CT scanning, bronchoscopy the examination of pleural fluid and biopsies. Other tests to detect metastasis include bone scans, bone marrow biopsy and CT scans of the brain and abdomen.
Metastases of Lung Cancer
Lung cancer most often spreads to the liver, the adrenal glands, the bones, and the brain. Lung cancer that has metastasized to the bone causes bone pain, usually in the backbone (vertebrae), the thighbones, and the ribs. Lung cancer that spreads to the brain can cause difficulties with vision and weakness on one side of the body.
Lung cancer may grow into certain nerves in the neck, causing a droopy eyelid, small pupil, sunken eye, and reduced perspiration on one side of the face; together these symptoms are called Horner’s syndrome (see Autonomic Nervous System Disorders: Horner’s Syndrome). Lung cancer may grow directly into the esophagus, or it may grow near it and put pressure on it, leading to difficulty in swallowing. Lung cancer may also spread through the bloodstream to the liver, brain, adrenal glands, spinal cord, and bone.
Treatment of Lung Cancer
Treatment for lung cancer depends on the cancer’s specific cell type, how far it has spread, and the patient’s performance status. If investigations confirm lung cancer, CT scan and often positron emission tomography (PET) are used to determine whether the disease is localised and amenable to surgery or whether it has spread to the point where it cannot be cured surgically. Treatment is usually a combination of surgery, chemotherapy and radiation therapy.
Surgery is usually the first option. Chemotherapy can be used as a first line treatment for lung cancer or as additional treatment after surgery. Radiation therapy can be directed at your lung cancer from outside your body (external beam radiation) or it can be put inside needles, seeds or catheters and placed inside your body near the cancer (brachytherapy). Radiation therapy can be used alone or along with other lung cancer treatments. Radiation therapy can also be used to lessen side effects of lung cancer.
Treatment may not be as effective for patients with bone or liver metastases from lung cancer, excessive weight loss, ongoing cigarette use, or pre-existing medical conditions such as heart disease or emphysema. At some point, if you and your oncologist or primary care physician agree that treatment no longer is advisable, hospice care can provide comfort.
Lung Cancer Prevention
If you smoke, the best way to prevent lung cancer and other serious conditions is to stop smoking as soon as possible.
However long you have been smoking, it’s always worth quitting. Every year you don’t smoke decreases your risk of getting serious illnesses, such as lung cancer. After 10 years of not smoking, your chances of developing lung cancer fall to half that of someone who smokes.
Quit Smoking therapists offer advice and encouragement to help you quit smoking. Your GP or pharmacist can also give you help and advice about giving up smoking.
Research suggests that eating a low-fat, high-fibre diet, including at least five portions a day of fresh fruit and vegetables and plenty of whole grains, can reduce your risk of lung cancer, as well as other types of cancer and heart disease.
There’s strong evidence to suggest that regular exercise can lower the risk of developing lung cancer and other types of cancer. Adults should do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity each week.
Cancers are a bit different to each other’s but the fears and worries patients have is similar. The best option to reduce stress and focus on proper treatment of cancer is to know more about it.
Find below cancer guides so that you are made aware of important aspects of it.