Introduction of Cancer

According to the statistics, cancer is the second causes of human’s death after a coronary heart diseases and it is a disease that due to the rapid growth of an abnormal cells in the body that not under control and has ability to invade other types of tissues. The history of cancer comes from Hippocrates, the Greek physician is believed to be the first person to use the word “carcinos”, which describes both the ulcer-forming and non-ulcer forming tumors spread and the word shortened to “cancer” after a long period. 

There are many types of cancer and each is classified by the organ or type of cell that is initially affected. The types of cancer can be grouped into different categories which are carcinoma, sarcoma, leukemia, lymphoma or myeloma and central nervous system cancers. Carcinoma which is cancer that begins in the skin or in tissues that line or cover internal organs, while sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is 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 where lymphoma and myeloma is the cancers that begin in the cells of the immune system and lastly is central nervous system cancers that begins in the tissue of brain and spinal cord. 

The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells. However, sometimes the orderly process had goes wrong. The genetic material (DNA) of a cell can become damaged or changed and producing mutations that affect normal cell growth and division. When this happens, cells do not die and new cells form when the body does not need them. The extra cells may form a mass of tissue called tumors. Tumors can grow and interfere with the digestive, nervous and circulatory systems. They can release hormones that alter body function. 

The tumors can be differentiate into two which is benign that is not cancerous and stay on one spot which means it will not spread to others part of the body while malignant tumor that considered as dangerous formed. The process is called invasion when malignant tumors manages to moves throughout the body using the blood or lymph systems and angiogenesis occur when cells manages to divide itself to making new blood vessels to feed itself. It is called to have metastasized when a tumor spreads to others part of body and leads to destroying of other healthy tissues.

The differences between normal cell division and cancer cell division.

The differences between normal cell and cancerous cell

Explaining cancer with animation 

Introduction of Lung Cancer

Lung cancer occurs when a malignant tumors grows on the bronchi where placed inside the lung and it is metastasizing as it have ability to spread to others part of the body. The most commonly spreads to the brain, bones, adrenal glands and liver, via any of three mechanisms that is direct extension, the blood vessels, or the lymph system. Direct extension occurs when a tumor grows rapidly in size such that it begins to touch an adjacent organ or structure, and penetrate itself into it. Tumor cells are also able to get into the blood and lymph circulatory systems and travel, one by one, to distant structures. According to the Malaysian Cancers Statistics in 2006, the statistics shown that there were 2,048 2006 cases of lung cancer registered with NCR, comprising of 1,445 of males and 603 of females and lung cancer is the third common cancer among populations in Peninsular Malaysia. Moreover, the Chinese were found to have higher incidence rate compared to Malay and Indians.

There are several types of lung cancer that can be identified by the size and appearance of the cancerous cells under a microscope and each kind of lung cancer arises in a different manner and behaves differently. The lung cancer can be categorized into two types which is small cell lung cancer and non-small cell lung cancer. The small cell lung cancer stands 20% of the lung cancer diseases and mostly related to the smokers that have smoking habits. The growth of cancerous cells in this type of cancer is more rapid and no symptoms in early stage. This often leads to the patients found that they have lung cancer after they reached critical stage. Therefore, in order to cure the disease, the combined of chemotherapy and radiation method are used to approached it.

Another form of lung cancer which is non-small lung cancer is the most common type of lung cancer in most of the patients. The non-small cell cancers differentiate more into three sub-types, which are squamous cell, adenocarcinoma and large cell lung cancer. The squamous cell of the non-small cell lung cancer which is begins in large section of the bronchi and it is a slowest progress type compare to others. This type of cancer disease often linked to history of smoking, while the adenocarcinoma occurs in the outermost tissue of the lung or inner of cell that lined to alveoli. The younger generation will have a higher chance and mostly girl that have no smoking habits. This probably they breathe in the chemical substance in gas formed from cigarette of smokers. The large cell lung cancers form as clusters of large undifferentiated cells, like the ademocarcinomas, they tend to occur at the periphery of the lung and growing and spreading more aggressively than squamous cell forms of lung cancer.

Different types of lung cancer cell.

Sticky, brown tar coats the lungs of tobacco smokers. Along with thousands of other damaging chemicals, tar can lead to lung cancer and acute respiration diseases.

Body Parts which Lung Cancer Affected

Lung cancer is cancer that starts in the lungs. Metastatic cancer to the lung is the cancer started somewhere else in the body and spread to the lungs. It finds its victim’s have men and women, smokers and non-smokers, young and old. It also damage on more than just the lungs. Lung cancer affects countless of body parts especially when it has spread. They spread because they need nutrition from the other part of the body they needed.

The victim’s blood flow will be affected. Every time the victim’s heart beats it sends blood holding carbon dioxide to the victim’s lungs which will exchange the carbon dioxide (exhaling) for oxygen (inhaling). Lung cancer could affect the victim’s breathing process, so the victim may not get enough oxygen into the victim’s blood, so the victim might have "dirty blood" (dirty blood being blood still holding carbon dioxide).

The disease begins to invade the lung tissue and any nearby tissue as the cancerous cells grow in lungs. When the tumor pushes against the chest, the victim may develop symptoms that include: a new or persistent cough; blunt, aching and constant pain in the chest (similar to that of a heart attack); shortness of breath or panting; scratchy voice or recurring bouts of respiratory ailments, such as bronchitis or pneumonia. Chest pain is symptomatic of lung cancer in nearly 25 percent of all sufferers.

The spreading of lung cancer to the bones causes tremendous pain and can make affected bones break more easily. Lung cancer that metastasizes in the brain causes several neurological disorders including stroke, reduced vision, loss of control and sensation in certain body parts. Lung cancer is very challenging to treat because of its ability to metastasize quickly.

Metastatic lung cancer in the bones usually produces discomfort in the backbone, ribs or thighs. Lung cancer that has attacked the nerves may cause sufferers to have pain in their shoulder that radiates along the outer arm. The vocal cords can also become paralyzed as well. Difficulty swallowing may result from the cancer making its way into the esophagus. If a large airway becomes obstructed, a portion of the lung can become easily to collapse and an infection may start to happen.

Symptoms of Lung Cancer

If you are either a smoker or have a history of smoking, it is important to check with doctor if you note any symptoms which are unusual for you such as such as knee pain, may be an early symptom of lung cancer. General symptoms, such as fatigue, decreased appetite, or even depression should advise you to seek a physician’s guidance.

The growth of the cancer and invasion of lung tissues and surrounding tissue may interfere with breathing, leading to symptoms such as persistent or intense coughing, pain in the chest shoulder, or back from coughing, changes in color of the mucus that is coughed up from the lower airways (sputum), difficulty breathing and swallowing, hoarseness of the voice, harsh sounds while breathing (stridor), chronic bronchitis or pneumonia, coughing up blood, or blood in the sputum.

Additional symptoms can present themselves in the newly affected area if the lung cancer spreads, or metastasizes. If cancer spreads to the brain, it may cause a number of neurologic symptoms which includes vertigo, headaches, or seizures. Besides, the liver may become enlarged and cause jaundice and bones can become painful, brittle, and broken.

It is also possible for the cancer to infect the adrenal glands resulting in hormone level changes. A common paraneoplastic syndrome associated with SCLC is the production of a hormone called adrenocorticotrophic hormone (ACTH) by the cancer cells, leading to oversecretion of the hormone cortisol by the adrenal glands. The most frequent paraneoplastic syndrome seen with NSCLC is the production of a substance similar to parathyroid hormone, resulting in elevated levels of calcium in the bloodstream.

Besides that, there are some non-specific symptoms which seen with lung cancers such as weight loss, fever, weakness, fatigue and swelling in the neck or face.

Symptoms of Lung Cancer
Cancer Location	Symptom
Primary tumor	Chest pain (increases with breathing in some cases)
	Cough (sometimes bloody)
	Fluid in the lungs (pleural effusion)
	Pneumonia (often repeated cases)
	Shortness of breath
	Wheezing
Local spread of the tumor	Changes in voice (hoarse)
	Changes in pupil dilation
	Trouble swallowing
	Strange sound when breathing (sometimes called stridor)
	Fluid accumulation in the lungs
Distant spread of the tumor	Weakness and/or numbness
	Trouble walking
	Pain in the bones
	Visual troubles
	Any neurological problem that has no other cause

Risk Factor of Lung Cancer

The major cause of lung cancer is cigarette smoking, representing 85 to 90 percent of all cases. Lung cancer is predominantly a disease of the elderly; almost 70% of people diagnosed with lung cancer are over 65 years of age. It is rare in people under age 45.

One of the reasons to cause lung cancer is being a passive smoker or "secondhand" smoker. Passive smoking or the inhalation of tobacco smoke by nonsmokers, who share living or working quarters with smokers, also is an established risk factor for the development of lung cancer. Research has shown that nonsmokers who reside with a smoker have a 24% increase in risk for developing lung cancer when compared with nonsmokers who do not reside with a smoker.

Radon gas is the second leading cause of lung cancer and is found naturally in soil and rocks. Radon gas is a natural, chemically inert gas that is a natural decay product of uranium. Uranium decays to form products, including radon, that emit a type of radiation. As with asbestos exposure, concomitant smoking greatly increases the risk of lung cancer with radon exposure. Radon gas can travel up through soil and enter homes through gaps in the foundation, pipes, drains, or other openings. Homeowners can purchase radon kits to test whether the gas exists in their home. If it does, measures can be taken to eliminate it. They stick to the lining of the lungs when these fibers are inhaled, which may eventually lead to lung cancer.

Besides, Carcinogens are a class of substances that directly damaging DNA, promoting or aiding cancer. Tobacco, asbestos, arsenic, radiation such as gamma and x-rays, the sun, and compounds in car exhaust fumes are all examples of carcinogens. Free radicals are formed that try to steal electrons from other molecules in the body when our bodies are exposed to carcinogens. These free radicals damage cells and affect their ability to function and divide normally. About 87% of lung cancers are related to smoking and inhaling the carcinogens in tobacco smoke. Even exposure to second-hand smoke can damage cells so that cancer forms.

Cancer can be the result of a genetic predisposition that is inherited from family members, such as individual genetic susceptibility, may play a role in the causation of lung cancer. It is possible to be born with certain genetic mutations or a fault in a gene that makes one have a chance to develop cancer later in life. Numerous studies have shown that lung cancer is more likely to occur in both smoking and nonsmoking relatives of those who have had lung cancer than in the general population. Recently, the largest genetic study of lung cancer ever conducted, involving over 10,000 people from 18 countries and led by the International Agency for Research on Cancer (IARC), identified a small region in the genome (DNA) that contains genes that appear to confer an increased susceptibility to lung cancer in smokers.

Air pollution from vehicles, industry, and power plants can raise the likelihood of developing lung cancer in exposed individuals. Up to 1% of lung cancer deaths are attributable to breathing polluted air, and experts believe that extended exposure to highly polluted air can carry a risk for the development of lung cancer similar to that of passive smoking.

Risk factor of lung's cancer.

Treatments for Lung Cancer

There are some type of treatment are available for the lung cancer patients. There are two type of lung cancer; they are non-small cell cancer and small cell cancer. These two types of lung cancer can have different treatment.  The first treatment surgery, this surgery is the surgical removal of the tumor and it is generally performed for limited-stage. This tumor is an abnormal mass of tissue, this is also known as cancer cell. This surgical removal of tumor is for the non-small cell cancer patients only which are stage 1 and sometimes stage two only; this surgical removal is for the cancer cell that has not spread beyond the lung. About 35% of lung cancer can be removal surgically , but this operation does not mean that it is 100% result is cure , although the tumor have been remove it can already spread and the cancer cell can be recur at a later time . More that 35% of lung cancer patients that have slow growing lung cancer after surgical removal can still alive five years after diagnosis. Beside that, this surgical removal of tumor nay not is possible for the patients that have some serious conditions, because in this operation they might have a limit ability to survive. This surgery is often too performed with the small cell cancer patients rather than the non-small cell cancer patients.

Besides that, radiation is one of the treatments for lung cancer. This treatment is suitable for both NSCLC and SCLC. This radiation therapy is the uses of high energy X-ray or other types of radiation to kill the cancer cell. This radiation therapy is a direct radiation toward and to kill the cancer cell. Radiation is also for the patients that are refuses to do surgical removal, if the tumor has spread to areas that are the serious part that the surgical removal is impossible. Thus, radiation therapy is generally only to minimize the tumor or is just to limit the growth of the cancer cell only. It is one of the ways to increase the survival rate. This radiation therapy can carry out on an outpatient basis; this is for external radiation only. For internal radiation the patient must be hospitalize. For those patients that has severe lung disease and with a lung cancer they are not recommended to have radiation therapy, this is because the radiation can further decrease the function of the lung. This radiation therapy is with the help of brachytherapy, it is something that use a small pellet of radioactive material placed directly into the cancer. This radiation therapy may not cause any risks when doing it, but it may cause some of the side effect such as nausea, vomiting or diarrhea.

The third treatment to treat lung cancer would be chemotherapy. Chemotherapy is referring to the administration of anticancer drugs to stop or to control the growth of cancer cell. These drugs enter the bloodstream and can affect cancer cell all over the body. This treatment can be given to both NSCLC AND SCLC patients. Very little patients who have SCLC can survive more than four month , and with this chemotherapy the survival time of the patients will be longer than the patient that without chemotherapy . Chemotherapy alone is not particularly effective in treating NSCLC, but it is combining with other therapy it may be able to prolong the survival time.  Chemotherapy is actually a pill. There are many combinations of drugs to kill the cancer cell, this call cycles, over a period of weeks to month, with break in between cycles. Unluckily, the drugs that used to kill cancer cell will also kill the normal dividing cell in the body. By using this kind of treatment can also cause many of the side effect, such as damage of blood cell, weight loss, hair loss, nausea, vomiting, diarrhea and mouth sores.

Another treatment for the lung cancer would be targeted therapy. This therapy is using the some target drugs to kill the cancer cell. This is targeted drugs, some of the example would be erlotinib and gefitnib, these two drugs is also for the patients that are already immune to the chemotherapy. One of the good thing of the treatment would be chemotherapy will kill the cancer cell and the normal cell in the body, but this targeted drugs will be in less damage to the normal cell compare to chemotherapy. 

Lists Antibodies and Tyrosine Kinase Inhibitors Currently under Clinical Investigation for Lung Cancer.

Survival Rate of Lung Cancer

This lung cancer survival rate is increasing in every year, more people die from lung cancer than breast cancer, colorectal cancer. The reason for lung cancer that has a high rate of death is due to the fact that is very difficult to treat. This is why the lung cancer survival rate is fairly low. The lung cancer survival rate will low this is also due to the level of cancer progression and the type of lung cancer that the patients have. The survival rate is also depending on the gender and the age of the patients, the youngest the patients the higher the survival rate and also women will also have the higher survival rate. Other than that, the survival rate for the patients that have non-small cell cancer have a higher survival rate compare to the patients that have small cell lung cancer only.

Survival Rate by Stage of Cancer at Diagnosis
Stage	Survival Rates
Stage 0	70-80%
Stage I	50%
Stage II	30%
Stage III	15%
Stage IV	Less than 2%