What is Lung Cancer?
Lung cancer results from the abnormality of the cell. The irregular reproduction of cells and lengthened cell life disrupts the body’s system of checks and balances resulting to uncontrolled division and proliferation of cells. This eventually forms tumors.
Tumors may be benign (usually harmless) or malignant (cancerous). While benign tumors can be usually removed and do not metastasize, malignant tumors display opposite features. Malignant tumors may allow entry of abnormal cells into the bloodstream of lymphatic system or to other parts of the body aside from its body part of origin. The tumor growths found in distant sites are known as metastases. Lung cancer tends to metastasize even at an early stage making it a very life-threatening cancer. It also is one of the most difficult cancers to treat. The most common metastases of lung cancer are found in the adrenal glands, liver, brain, and bone.
The lung is also a very common site where tumors from other cancers appear. Tumor metastases are made up of similar type of abnormal cells from its primary source. If ovarian cancer spreads through blood into the lungs, the cancer cells found in the lungs is called metastatic ovarian cancer and is not lung cancer.
Like many other cancers, lung cancer starts when oncogenes are activated or tumor suppressor genes are inactivated. Oncogenes are genes make people more susceptible to cancer. Proto-oncogenes turn into oncogenes when exposed to certain carcinogens. Mutations in the K-ras proto-oncogene may result to adenocarcinomas. The epidermal growth factor receptor or EGFR control cell proliferation, apoptosis, angiogenesis, and tumor invasion.
Majority of lung cancers are carcinomas or malignancies from epithelial cells. Two main types of lung carcinoma are non-small cell and small-cell. Such classification is based on histological criteria and has significant impact on clinical management and prognosis of the disease.
Non-small cell lung carcinoma (NSCLC) has three main sub-types: squamous cell lung carcinoma, adenocarcinoma, and large cell lung carcinoma. Squamous cell lung carcinoma usually originates close to a central bronchus. Well-differentiated squamous cell lung cancers usually grow slower than other cancer types. Adenocarcinoma usually originates in the peripheral lung tissue where most cases are associated with smoking. However, for non-smokers with lung cancer, adenocarcinoma is most common. Adenocarcinoma has a subtype called bronchioloalveolar carcinoma which is more common in female never-smokers.
Small cell lung carcinoma (SCLC), also known as the oat cell carcinoma, is less common. It usually originates in larger airways and rapidly grows allowing it to become large. This lung cancer type is strongly associated with smoking.
The main causes of lung cancer include carcinogens (smoking), ionizing radiation, viral infection, familial predisposition, and prior history of lung cancer. Exposure to the given causes changes to the DNA in the tissue lining the bronchial epithelium. The more damaged the tissue becomes, the greater the possibility of developing lung cancer.
What is lung cancer’s most common cause? Lung cancer incidents are strongly correlated with smoking. Passive smoking or second-hand smoking increases the risk of developing lung cancer.
Other causes have also been studied. Abestos fibers which are silicate fibers that remain in the lungs for a long time (possibly a lifetime) may be inhaled and can cause lung cancer. Radon gas, a decay product of uranium, emits a type of ionizing radiation possibly causing lung cancer. Human papillomavirus, JC virus, simian virus 40 (SV40), BK virus, and cytomegalovirus may affect cell cycles and allow uncontrolled cell division. Those with a family history of lung cancers have increased risks of lung cancer. Survivors of lung cancer have greater risks of developing lung cancer again.
Symptoms suggesting lung cancer include dyspenea or shortness of breath, hemoptysis, chronic coughing, wheezing, chest pain, cachexia (weight loss), fatigue, loss of appetite, hoarse voice, clubbing of the fingernails, and difficulty of swallowing.
Screening uses medical tests to be able to detect disease in asymptomatic people or those who have a disease without displaying symptoms. Screening tests for lung cancer may be chest radiograph or computed tomography (CT) of the chest.
There is a wide range of diagnostic procedures and tests used to diagnose lung cancer. These include: physical examination, chest x-rays, magnetic resonance imaging (MRI), positron emission tomography (PET) scanning, bone scans, sputum cytology, bronchoscopy, fine needle aspiration (FNA), thoracentesis, major surgical procedures, and blood tests.
The stage of a cancer is the extent to which metastases are found in the body. Staging involves examination of a cancer’s size and presence of metastases in the lymph nodes or in other organs of the body. Staging is important to distinguish treatment that would best address a particular lung cancer case since lung cancer therapies are targeted toward specific cancer stages. Staging of a cancer is also critical in estimating the longevity of the patient’s life. Later stages of lung cancer have worse prognosis than earlier stages.
Lung cancer treatment depends on the cancer’s specific cell type, case of metastases (if any), and the patient’s performance status. Common treatments are surgery, chemotherapy and radiation therapy.
The chance for cure and survival of cancer is called prognosis of lung cancer. Prognosis depends on position origin of the cancer, size, type, presence of symptoms and the overall health condition of the patient.
Prevention is the most cost-effective way to fight lung cancer. Elimination of tobacco smoking is one of the best preventive measures relating to lung cancer. Smoking cessation is the best way to lessen the risk of having lung cancer. Prevention during the younger ages is a more effective preventive measure.
What is lung cancer patient faced with? Lung cancer patients must communicate with their health care providers. Learning new terminology and aspects of treatment are helpful in the process of communication. Emotions play a major role in facing the challenges of having cancer. Understanding and respecting personal emotions, sharing them with other patients and listening to their experiences will help a patient get through with the treatments as well as the difficult days. The patient must understand that the disease does not define his personality but is an unusual challenge that must be faced with courage and acceptance with the help of a social support system.