4/5/18: Just like all the previous posts, I really don’t know the source of this and I have no idea where I got my sources. Forgive the 16 years old me for not knowing the importance of citing sources
Lung cancer
Lung cancer is a disease due to uncontrolled cell growth in tissues of the lungs. Most cancer starts from the lung, and is known as primary lung cancer. It is the cancer that caused the most death in Singapore’s male among all other cancer. Worldwide, lung cancer is the most common cause of cancer-related death in both women and men. In the United State, 15% of the people diagnosed with lung cancer survive five years after the diagnosis. It is responsible for the death of 1.38 million patient annually, as of 2008.
The most common cause of lung cancer is smoking. Long term exposure to tobacco smoke causes 80-90% of lung cancer. 10-20% of lung cancer are from non-smoker. Non-smoker usually get lung cancer due to genetic factors, radon gas, air pollution(second-hand smoke).
Signs and symptoms:
1. Respiratory symptoms – coughing(sometimes with blood), wheezing, shortness of breath
2. Systemic symptoms – Weigh loss, fever, clubbing of the fingernails, fatigue
3. Symptoms due to local compress – Chest pain, bone pain, superior vena cava obstruction, difficulty swallowing.
If the cancer grows in the airway, it can cause breathing difficulties.
For many people, when they have the symptoms and seek medical attention, the cancer have spread out from the lungs. It usually spread to the brain, bone, adrenal glands, the opposite unaffected lungs, liver, pericardium and kidney. About 10% of people with lung cancer do not have any symptoms at diagnosis.
Causes:
1. Smoking – Smoking is the main contributor to lung cancer. Nicotine, which is found in cigarettes, can depress the immune response to cancerous growths in exposed tissue. Passive smoking(inhalation of second-hand smoke) is also the main cause of lung cancer in non smoker.
2. Radon gas – a colorless and odorless gas that is generated by the breaking down of radium, which in turn is also the decay product of uranium. The radiation decay products ionise genetic material, causing mutations that can be cancerous.
3. Asbestos
4. Air pollution – It has a small effect on increasing risk of lung cancer. It is estimated to account for only 1-2% of lung cancer. PM2.5 and sulfate aerosols slightly increase the risk of lung cancers. People exposed to indoor coal smoke also have increases risk.
5. Genetics – About 8 to 14% of lung cancer is due to inherited factors.
Prevention is better than cure. It is also the most cost effective means to decrease lung cancer development. Many countries have made efforts to reduce pollutions that cause lung cancers. Bhutanhad completely banned smoking since 2005. Many countries set limit to where smokers can smoke to prevent non smoker from getting lung cancer due to passive smoking. Best way to prevent lung cancer ourselves, is to not smoke at all. And also to encourage people around to not smoke. It is said that our diet have no link to lung cancer. Screening for lung cancer can help too.
Treatment:
1. Surgery
2. Radiotherapy
3. Chemotherapy
4. Palliative care
Of all the people diagnosed with lung cancer, only about 15% survive for five years after diagnosis. There are four stages for lung cancer. Below shows the five-year survival rate.
Stage IA(one A):50% for NSCLC(Non-small cell lung carcinoma) and 38% for SCLC(Small cell lung carcinoma)
Stage IB(one B): 47% for NSCLC and 21% for SCLC
Stage IIA(two A): 36% for NSCLC and 38% for SCLC
Stage IIB(two B): 26% for NSCLC and 18% for SCLC
Stage IIIA(three A): 19% for NSCLC and 13% for SCLC
Stage IIIB(three B): 7% for NSCLC and 9% for SCLC
Stage IV(four): 2% for NSCLC and 1% for SCLC
For NSCLC, it is best to have complete surgical resection of Stage IA disease, to have up to 70% five-year survival. For SCLC, the overall five-year survival is about 5%. The average survival time for limited stage disease is 20 months, with 20% five year survival rate.
