With 164,000 new cases in the United States and 20,600 new cases diagnosed in Canada every year, lung cancer is the third most common type of cancer in the North America. Although ranked below the prostate and breast cancer on the prevalence, lung cancer is the leading cause of cancer deaths in the United States and Canada. In the United States, a five-year survival rate for lung cancer is relatively low at 14 percent, and the number rose only to 50 percent if the cancer is detected early.
The biggest risk factor for lung cancer is cigarette smoking, behavior that gives 85 to 90 percent of all cases. Long-term exposure to secondhand smoke also causes lung cancer. The main risk factors include exposure to workplace chemicals carcinogenic, especially asbestos and organic chemicals such as vinyl chloride. Exposure to radon gas and other air pollutants also increases the risk of lung cancer, especially among smokers.
Oxygen reaches the blood through a series of tubes and passages in the lungs. It is divided into so-called respiratory tract, which is divided into branches called bronchioles smaller. At the end of the bronchioles are tiny air sacs known as alveoli. Most lung cancer begins in the lining of the respiratory tract, but cancer can also start in the trachea, bronchioles, or alveoli. Approximately 20 percent of lung cancer patients had small cell carcinoma, a type of lung cancer that usually starts at around the respiratory tract. Squalors cell carcinoma also often comes near the bronchi. It contributes about 30 percent of all lung cancers.
Lung cancer frequently goes to be considered in the early stages. Patients can develop persistent cough or a finding that the worsening of chronic coughing. Other symptoms include chest pain, shortness of breath, hoarseness, coughing up blood from the respiratory tract fluids, and frequent bouts of bronchitis or pneumonia. Sometimes early symptoms of lung cancer are bone pain, headache, dizziness, or signs of other diseases that have metastasized.
People with early warning signs should consult their family doctor, who will evaluate the symptoms and can refer patients to doctors who specialize in cancer. A doctor will first take the patient’s medical history to learn about current symptoms, past history of disease, and family members diagnosed with cancer. The procedures used in the physical examination depend on patient’s clinical symptoms and may include a digital rectal examination, where doctors use a gloved finger to gently check the smoothness of rectal lining. Doctors can perform breast examinations on female patients, where the soft breast was investigated to feel a lump or mass that is not unusual.
During the exam your doctor may use a thin tube called an endoscope to look radiant tumor in the internal body cavity. Endoscopic procedures are used depending on the organ or body cavity inspection. In gastric endoscopy, the doctor feeds a specialized endoscope into the throat to examine the layers of the esophagus, stomach and first part of the small intestine. Colonoscopy uses a longer flexible instrument to view the entire length of the colon.
A number of laboratory tests may help narrow the diagnosis. In a Pap smear, cervical epithelial cells removed from plastic with a small brush. These cells are examined under a microscope for cell changes that are signs that the cancer can develop as well as signs of malignancy. If clinical signs suggest colorectal cancer patients, doctors may find blood in the stools with fecal occult blood tests. A small sample of stool is smeared on the patient card coated with a chemical called guaiacum, which reacts with blood. Cards were analyzed in the laboratory for occult (hidden) blood. Other tests for signs of tumors, the chemicals present in higher levels of certain cancers when present. For example, a prostate-specific antigen (PSA) test measures the level of prostate-specific antigen in the blood.
These include computed tomography (CT) and Magnetic Resonance Imaging (MRI) scan. CT and MRI scans use a computer to form three-dimensional images of tumor and surrounding tissue. X-ray called a mammogram breast images help physicians detect and evaluate breast cancer. Ultrasound scan of high-frequency sound waves bounce of the tumor and surrounding tissue to create an image of the tumor. Multimodality display technique combining images from multiple imaging devices into a single image, giving the final three-dimensional images with much greater detail. Computer aided diagnosis using sophisticated computer technology programming called artificial intelligence to scan X-ray mammograms and to help search for signs of cancer and offers an automatic second opinion.