Lung cancer is an uncontrolled growth of cancer cells in lung tissue that can be caused by a number of carcinogens, especially cigarette smoke. Lung cancer is the largest killer cancer that has killed nearly 90% of its patients or 30% of all cancer deaths. About 1.56 million people die each year from lung cancer.
Lung Cancer
If left untreated, the growth of cancer cells can spread beyond the lungs through the process of metastasis to nearby tissues. Often lung cancer comes from abnormal cell growth in epithelial tissue. The most common symptoms of this cancer are coughing (including coughing up blood), weight loss, shortness of breath, and chest pain. Lung cancer causes death because the lungs are part of the respiratory system in humans. If breathing is hampered, then the oxygen supply throughout the body is also hampered.
The people most at risk of lung cancer are people who are often exposed to cigarette smoke (about 80-90% of the total lung cancer patients) although the person is not a smoker who is often called a passive smoker (about 10-15% of the total sufferer). Other causes are genetic factors, exposure to radon gas, asbestos, and air pollution.
Treatment of lung cancer depends on the stage of cancer and the overall health condition of the sufferer. Common treatments in patients include surgery, chemotherapy, and radiotherapy. 16.8% of people in the United States survive up to five years after being diagnosed, whereas in developing countries life expectancy is shorter.
Symptoms of Lung Cancer
Symptoms of lung cancer can be grouped into three:
- Respiratory symptoms: coughing, coughing up blood, and shortness of breath.
- Systemic symptoms: weight loss, fever, and fatigue.
- Symptoms due to pressure from cancer cell growth: chest pain, bone pain, and difficulty swallowing.
Causes of Lung Cancer
Cancer develops due to genetic damage to DNA and epigenetic changes. These changes can affect cell function including cell proliferation, cell death (apoptosis), and DNA repair. Here are some causes of lung cancer.
- Smoking
Smoking is by far the leading cause of lung cancer. Cigarette smoke contains at least 73 carcinogens (cancer-causing) including radioactive polonium. In developed countries, 90% of deaths from lung cancer in men during 2000 were caused by smoking (70% for women). Worldwide, 80-90% of the causes of lung cancer are smoking habits.
Passive smokers (inhaling cigarette smoke emitted by others who are smoking) can also cause lung cancer, even if the person is not a smoker. The increased risk of lung cancer is directly proportional to the more often a person is exposed to cigarette smoke. Those living with a smoker increased the risk by 20-30% while those working in a smoke-contaminated environment had a 16-19% risk. Cigarette smoke that has been emitted by smokers is more dangerous than smoke that has just been smoked from cigarettes. 3,400 passive smokers die each year from lung cancer in the United States.
Marijuana cigarette smoke contains the same carcinogens as tobacco cigarette smoke. However, there is no increased risk of developing lung cancer in marijuana smokers even though they already include heavy marijuana smokers.
- Radon Gas
Radon is a colorless and odorless gas produced by the radioactive decomposition of radium that is the result of the decay of uranium found in the Earth's crust. People exposed to radon gas can develop mutations that sometimes turn into cancer. Radon gas is the second leading cause of lung cancer in the United States, with about 21,000 deaths annually. Each radon gas concentration increases by 100 Bq/m³, the risk of developing lung cancer increases by 8-16%. Radon gas is sometimes contained in groundwater and out of the ground.
- Asbestos Dust
Asbestos can cause a variety of diseases of the lungs including lung cancer. Smoking tobacco and asbestos dust have a synergistic effect on the formation of lung cancer. A smoker who works with asbestos has a 45-fold risk of lung cancer. Asbestos can also cause pleural cancer (mesothelioma)
- Air Pollution
Outdoor air pollution does not have a major impact on the increased risk of lung cancer. Particulates and sulfates emitted by motor vehicle fumes slightly increase the risk. Nitrogen dioxide can increase the risk of lung cancer by 14%. Overall air pollution only increases the risk by 1 to 2 percent.
Indoor air pollution such as residual cooking fumes or charcoal stoves can increase the risk of lung cancer. Women who were exposed in the kitchen using a coal stove had a two-fold increased risk of developing lung cancer compared to regular stoves. This accounted for 1.5% of deaths from lung cancer.
- Genetics
About 8% of lung cancers are due to genetic factors. People with lung cancer had a 2.4 times increased risk. This may be due to gene combines and polymorphisms in chromosomes.
Other Causes of Lung Cancer
There are several other substances that can cause lung cancer. Here are some cancer-causing substances according to IARC (International Agency for Research on Cancer):
- Some heavy metals such as aluminum, cadmium, chromium, beryllium, iron, steel, nickel, and arsenic.
- Some imperfect combustion results such as coal, cooking oil, and diesel engine fumes.
- Radiation such as X-rays, gamma rays, and plutonium.
- Some toxic gases.
- Production of rubber and silica dust.
The Process of Lung Cancer (Pathogenesis)
Just like most other cancers, lung cancer begins with activation of the oncogene or inactivation of tumor suppressor genes. Carcinogens cause gene mutations that encourage the development of cancer. Epigenetic changes such as DNA methylation can lead to the inactivation of tumor suppressor genes.
Lung Cancer Diagnosis
Chest X-rays are one way of early detection if a person experiences symptoms of lung cancer. With X-rays, mass changes, mediastinum dilation, atelectasis, pneumonia, or pleural effusion can be detected.
Visible signs of lung cancer during a chest X-ray may indicate other diseases such as tuberculosis, fungal infections, metastatic cancer, or pneumonia. X-rays should not be performed regularly to avoid overexposure to radiation.
Lung Cancer Prevention
Here's how to prevent lung cancer. Smoking is the most effective way to prevent the development of lung cancer.
- Smoking Ban
While most industries that produce carcinogens have been banned, the tobacco cigarette industry is still rampant. Eliminating tobacco cigarettes is the most effective way to reduce the number of people with lung cancer. Quitting smoking is the most effective way for a person to avoid lung cancer.
Currently, in some countries, there have been regulations banning smoking in public places to reduce passive smokers. Such public places such as restaurants, parks, inside public transport, offices, government buildings, etc. Even Bhutan prohibits smoking in all places. The WHO is calling on the government to ban explicit cigarette advertising to prevent young people from smoking. The ban reduced tobacco consumption by 16%.
- Other Prevention Strategies
Long-term use of vitamin A supplements, vitamin C, vitamin D, and vitamin E does not reduce the risk of lung cancer. Some research shows that people who eat a lot of vegetables and fruits tend to have a lower risk of lung cancer. But reducing smoking is the most effective way. Further research has not shown a clear link between food and lung cancer risk.
Lung Cancer Treatment and Treatment
Treatment of lung cancer depends on the type of cancer cell, the rate of its spread, and the health condition of the sufferer. Common treatments include chemotherapy, radiation therapy, and surgery.
- Surgery
Surgery in the form of removal of cancer cells. However, if cancer has spread to a vital point, surgery cannot be performed. Blood tests and lung function tests are used to assess whether the sufferer is eligible for surgery. If lung function tests show tidal volume is thinning, surgery becomes unable to perform. Surgery in the early stages of cancer is usually the removal of the lung lobe.
- Radiotherapy
Radiotherapy is often done in conjunction with chemotherapy. Radiotherapy is often used by patients who no longer allow surgery.
- Chemotherapy
Chemotherapy depends on the type of cancer. Early-stage lung cancer can be done by chemotherapy and radiation. Two drugs used for chemotherapy one is cystplatin or carboplatin, and the other is gemcitabine, paklitaksel, dosetaksel, penetration, etoposide, or vinorelbin.
- Palliative Care
Palliative care can be done even when the patient is still using chemotherapy. Palliative care is interdisciplinary care that focuses on the patient's illness. The goal is to ease the burden of the disease. Palliative care costs a fortune.
Lung Cancer Prognose
Of all lung cancer patients in the United States, 16.8% survive at least five years after diagnosis. Whereas in the UK less than 10%. In developing countries, it is even worse. In the UK, around 70% of sufferers survive at least a year since being diagnosed.
According to data provided by the National Cancer Institute, the average age when diagnosed with lung cancer in the United States is 70 years, and the average age of death is 72 years. In the United States, better results are seen in those who have health insurance.
Types of Lung Cancer
Lung cancer can be divided into two types namely SCLC (small cell lung cancers) or also called wheat cell cancer, and NSCLC (non-small cell lung cancers). SCLC covers approximately 20% of lung cancer and is very aggressive and can grow rapidly. 99% of SCLC sufferers are smokers. NSCLC is the most common type of lung cancer that covers 80% of all lung cancers. Most NSCLC sufferers are smokers.
The epidemic of Lung Cancer
Worldwide, lung cancer is the most common cancer suffered by men. As for women, lung cancer is the third most common cancer after breast cancer. In 2012, there were 1,820,000 new cases and 1.56 million people died from lung cancer. The data represents 19.4% of all cancer deaths. The highest mortality rates were in North America, Europe, and East Asia. A third is in China. Cases of lung cancer in Africa and South Asia are relatively low.
The most vulnerable people with lung cancer are smokers over the age of 50. For every 3-4 million smoked cigarettes, one death from lung cancer occurs. Smoking culture has existed in a number of countries around the world and is even becoming a trend. Once it is known that passive smokers are more at risk of lung cancer, the government is vigorously restricting smoking, especially in public places. Emissions of motor vehicles, factories, and power plants can also increase the risk of lung cancer.
History of Lung Cancer Discovery
Lung cancer is very rare before cigarettes are present. Even before 1761, it had not been recognized as a disease. In 1878, lung cancer was only 1% of all cancers. In the early 1900s, it increased to 10-15%. In 1912, there were 374 cases of lung cancer worldwide. In 1929, dr Fritz Lickint acknowledged that there was a link between smoking and lung cancer, which led to an aggressive anti-smoking campaign. Research in the 1950s in England was the result of the first study to show strong epidemiological evidence of a link between lung cancer and smoking. In 1964, the United States recommended smokers quit smoking.
The link between radon gas and lung cancer was first discovered in miners in the Ore Mountains. The area is home to silver, uranium, and radium including radon gas. Radon gas was confirmed as the cause of lung cancer in 1960.
Radiotherapy has been in use since the 1940s. In the 1970s, chemotherapy was successfully developed.
The direction of Lung Cancer Research
The current direction of lung cancer research is immunotherapy that encourages the immune system to attack tumor cells, epigenetics, and a combination of chemotherapy and radiotherapy.
Conclusion About Lung Cancer
After knowing the various dangerous risk factors of lung cancer, you should live a healthy lifestyle from now on. This can be done by quitting smoking, exercising regularly, and eating nutritious foods.
Reference: Lung cancer en.wikipedia.org
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