Lung Cancer

Lung cancer is a serious health and social problem in the developed countries. It is the most common type of cancer that caused approximately 1.59 million deaths in 2012. There are several reasons for such statistics, but the main reason is the delays in seeking health care. Typically, lung cancer affects people aged from 40 to 60 years old. The symptoms of lung cancer depend on the location and extent of the tumor. A person with lung cancer may experience such symptoms as a cough, shortness of breath, chest pain, coughing up blood, and weight loss. Identification of most of these symptoms should alert a person to seek immediate medical attention. The disease is amenable to treatment in the early stages. Usually, doctors can cure the disease or at least achieve a stable remission. Therefore, everyone should be aware of symptoms of lung cancer, especially at-risk groups, which include smokers and residents of large cities.
The primary cause of lung cancer is smoking. About 80% of patients with this condition are smokers. The remaining 20% of cases of cancer are associated with exposure to such factors as the presence of radon in the air in closed premises and contact with asbestos dust, heavy metals, and chloromethyl ether. Nonetheless, smoking is the main contributor to lung cancer.
The treatment of lung cancer remains a significant challenge even today. The treatment of the disease may include surgery, chemotherapy, radiation therapy, the CyberKnife robotic radiosurgery system, and palliative care. The success of treatment depends on several factors, namely the histological type of tumor, its size, and the presence of metastases. Taking these factors into account, the doctor will determine a strategy for further treatment of lung cancer. In most cases, the individually selected set of measures will provide an optimum effect in each particular case.
Doctors identify four stages of the disease. At the first stage, the tumor is localized in one place. It has no metastases and its size rarely exceeds 1.5 inches. Typically, the symptoms of lung cancer are either absent or hardly differentiated at this stage. The patient may experience a cough, headache, weakness, fatigue, malaise, increased body temperature, and decreased appetite. It is impossible to diagnose the disease only on the basis of complaints. The diagnosis requires fluoroscopy or magnetic resonance imaging.
At the second stage, there are first isolated metastases in regional lymph nodes. The tumor gradually increases in size. The diagnosis of lung cancer based only on symptoms is still difficult; however, the symptoms should already alert the patient and doctor. This stage is marked by hemoptysis, rales during breathing, chest pain, and general symptoms of weakness, high temperature, fatigue, loss of appetite, and headache.
The diagnosis of the third stage of lung cancer is based on the subjective complaints and medical examination. The decisive factor is the development of metastases in all regional lymph nodes and some remote ones going beyond the lungs. The symptoms are similar to the ones of the second stage but differ with more intensity. A wet cough, mucus, blood as well as pus in the sputum, wheezing, shortness of breath, weight loss, and difficulty in swallowing are common at this stage.
If the doctor diagnoses lung cancer at the fourth stage, once can expect the most severe symptoms. They may include a painful cough and hemoptysis. The pain in the sternum may vary in intensity, from the periodic and weak to the constant and severe. Often, the patient can relieve pain only via narcotic drugs. During this stage, the tumor significantly grows affecting other organs.
Lung cancer is not a hereditary disease, but the tumor cells may develop some genetic lesions, including the activation of dominant oncogenes and inactivation of tumor suppressor genes. It has been discovered that the tumor cells have to accumulate more than 10 of such lesions to become clinically evident. Dominant oncogenes are characterized by the point mutations in the coding regions of the RAS family of oncogenes. Amplification, intragenic restructuring, and dysregulation of transcription of MYC oncogenes are also peculiar to them. In addition, overexpression of BCL2 gene, ERBB2 gene, and telomerase gene are common to the oncogenes.
Histologically, lung cancer is divided into two types, namely small-cell lung cancer (SCLC) and non-small-cell lung cancer. SCLC occurs in 15% of patients while the other type is diagnosed in 85% of patients with lung cancer. SCLC is characterized by early metastasis to the mediastinal lymph nodes, adrenal glands, bones, liver, and brain. Thus, the surgical treatment of this form of cancer is not used. At initial stages, SCLC responds well to chemotherapy and radiotherapy. In turn, the surgical removal of the tumor is performed at the early stage of NSCLC.
As for the genes, mutations of TP53 gene and RB1 gene are detected in more than 90% of patients with SCLC. In NSCLC, TP53 mutations are found in 50% of cases, while RB1 gene mutations are found only in 20% of cases. CDKN2A gene mutations are detected in approximately 10% of patients with SCLC and in more than 50% of patients with NSCLC. Probably, RB1 gene and CDKN2A gene play a similar role in cell cycle regulation.
Although lung cancer is not hereditary, the signs of predisposition to the disease can be traced. They include the inheritance of RB1 gene mutations and TP53 mutations; a twofold or even threefold increase in the risk of lung cancer and other cancers in first-degree relatives, including non-smokers; a frequent combination of lung cancer and chronic obstructive pulmonary disease.
Thus, the identification of genetic defects inherent in the tumor cells allows experts to diagnose lung cancer at the early stage or prevent it using medications. The first changes occur at the molecular genetic level but not in the histological one and, therefore, they can be used for diagnostic purposes and determination of the method of treatment.
There are several ongoing research studies on lung cancer; however, findings of the researchers from Imperial College London represent the greatest interest in terms of the potential treatment. Scientists have discovered a key molecule that can disable the ability of cancer to spread throughout the body. Often, the metastases kill a person when the main tumor is removed as their outgrowth affects adjacent organs and tissues. The discovery of the key molecule may help scientists to develop the treatment that will prevent the spread of cancer in the human body. Moreover, it may contribute to the development of a test that will help doctors to estimate the likeliness of metastatic outgrowth.
About the author: Jim Baker is a bachelor in English philology and literature at Oregon University. He is currently working as one of the best writers at the https://essaywritingstore.com/ He also studies feminine psychology