Lung cancer (or carcinoma) is one of the most common cancers diagnosed in both men and women. There are two general categories of lung cancer, small cell lung cancer (SCLC) or non-small lung cancer (NSCLC). There are several reasons for making the distinction between NSCLC and small cell lung cancer. The cancers appear differently when examined under the microscope. The early symptoms tend to be different. Treatment approach is different.
There are several varieties of non-small lung cancer. These include large cell lung cancer, squamous cell lung cancer and adenocarcinoma of the lung. While most lung cancers are directly related to cigarette smoking or other tobacco exposure, other chemicals and exposures to agents such as asbestos, radon, chromium, nickel and arsenic may be associated with the development of lung cancer.
Squamous cell carcinoma of the lung accounts for about 30% of cases of non-small cell lung cancer. Most squamous cell carcinoma starts in the central areas of the lungs. These tumors may cause symptoms of coughing up blood at an earlier stage than tumors located on the edges of the lungs, such as adenocarcinoma. The proportion of lung cancers labeled squamous has been steadily decreasing, possibly because people began inhaling smoke more deeply into more peripheral areas of the lung after the advent of filtered cigarettes.
Squamous cell carcinoma often spreads (metastasizes) to other parts of the body because of the constant flow of fluids (blood and lymph) through the lungs. The fluids can carry cancer cells to nearby areas, such as the chest wall, neck, esophagus or heart. Unless the cancer is diagnosed and treated early, it frequently spreads throughout the body. Outside the chest, this lung cancer commonly spreads to the bones, brain, liver and adrenal glands. In addition, many lung cancers may secrete unusual types of chemicals that circulate in the blood stream. Squamous cell lung cancer may secrete a substance that may cause abnormalities of the calcium levels of the bloodstream. This can lead to abnormalities of kidney function as well. When cancers secrete chemicals that cause other portions of the body to react, this phenomenon is called a "paraneoplastic phenomenon."
Symptoms
Although some cancers initially have no symptoms, others are diagnosed during an evaluation for any of the following:
A persistent cough Coughing up of blood (hemoptysis) Unexplained weight loss or loss of appetite Shortness of breath or wheezing Fatigue Increased mucus secretions or phlegm coughed from the lungs Difficulty swallowing Pain in the chest, shoulder or arm Recurrent pneumonias in the same place Bone pain Hoarseness Headaches, confusion or seizures Swelling of the face, neck or upper extremities Enlargement of the ends of fingers and toes (digital clubbing) High levels of calcium, leading to abnormalities of kidney function and fatigue Diagnosis
Squamous cell carcinoma often is discovered on a chest X-ray, where it appears as a dark, shaded area. Other imaging studies, such as computed tomography (CT) or magnetic resonance imaging and positron emission tomography (PET scans), may be used to further determine the size, shape and location of the tumor.
These tests help to find the best place to obtain a sample of the tumor to determine whether it is a type of lung cancer or whether the cancer spread to the lung from another place outside the chest. The type of cancer affects what treatment you should get.
Other tests that can be used to diagnose this type of cancer include:
Thoracentesis A needle is used to remove pleural fluid, the fluid between the lung and the chest wall. This fluid is examined for cancer cells. This procedure may be done when the chest X-ray shows an abnormal accumulation of fluid. Mediastinoscopy This is a surgical procedure that lets the doctor remove lymph nodes from the lungs through very small incisions. The incision is generally made at the bottom of the neck, right above the chest bone to allow a specialized tube to be inserted into the central portion of the chest. The surgeon then is able to collect certain cells of the lymph nodes in the central portion of the chest. The cells and pieces of tissue from the biopsy are then sent to a pathologist who tests them for cancer. Needle biopsy or fine-needle aspiration In this procedure, a needle is used to remove (aspirate) fluid or tissue for testing from lymph nodes, a lung mass or from an area in the bone marrow or other organ where the tumor may have spread. Bronchoscopy A flexible, fiber-optic viewing instrument is passed through the airway into the lung. The instrument allows the doctor to examine the tumor directly and to remove cells for examination. Occasionally, surgery is done to remove the tumor first and then the diagnosis is made.
PET scanning is used to help make the initial diagnosis and to help determine whether the lung cancer has spread and the extent of spread. This test is able to detect, using very sophisticated chemicals, the metabolic activity of abnormal cancer cells by measuring their uptake of a sugar substance (glucose). Recent studies have shown improved accuracy in detecting cancer spread to other areas of the body when PET scanning has been compared to CT scanning. This type of information will greatly influence the type of treatment that is offered to the patient.
Expected Duration
Without treatment, cancer will continue to grow. As with any cancer, even if large cell carcinoma seems to have disappeared (gone into remission) after treatment, there is a chance the cancer can return.
Prevention
Quit smoking and avoid secondhand smoke. Tobacco smoke is the main risk factor for most types of lung cancer, including large cell. Although studies are looking for ways to diagnose lung cancer earlier, no test has been proven effective yet.
Some recent studies have examined the role of specialized types of CT scanning of the chest, trying to diagnose lung cancers earlier. These studies have suggested that abnormalities of the lung can be detected earlier, some of which turn out to be lung cancers. However, many of the irregularities seen on CT scanning turn out not to be cancer. Most importantly, screening for lung cancer has not yet shown an improvement in prognosis or survival.
Treatment
Your doctor will choose a therapy based on the size and location of the tumor, which define the cancer's stage. Stage I tumors are small and have not invaded the surrounding tissue or organs. Stage II and III tumors invade surrounding tissue and/or organs and have spread to lymph nodes. Stages I through III are further divided into two categories A and B. Stage IV tumors have spread outside the chest area.
After the stage and extent of the cancer has been determined, the cancer will need one or several types of treatment. This could include the surgical removal of the cancer, treating the area of the cancer with radiation, or using chemotherapy or other newer types of treatment that hold promise for lung cancer patients. In general, treatments are meant to shrink the tumor or remove the tumor. Even after treatments are done, patients with lung cancer are continued to be followed for months to years, since even if the cancer has shrunk, it still may regrow or return at some later time.
Surgery is the primary treatment for large cell carcinoma that has not spread. For small, localized tumors, it might be possible to remove only a small section of the lung. More extensive cancer might require removing one lobe of the lung or the entire lung. Radiation therapy and chemotherapy may be combined with surgery to help prevent the cancer from coming back.
People with severe medical problems that make it difficult for them to withstand surgery may receive radiation therapy to shrink the tumor or a combination of radiation and chemotherapy . In addition, newer forms of radiation therapy, using a machine called a Cyberknife, may be able to now treat lung cancers once thought to be more difficult to treat. The Cyberknife is able to use very focused beams of radiation and therefore allows less damage to the normal tissues surrounding the cancer.
When there is significant tumor spread, chemotherapy drugs may be recommended to slow cancer growth even if it cannot be cured. Chemotherapy has been used to decrease symptoms in advanced cases of lung cancer. Unfortunately, squamous cell carcinoma does not respond to chemotherapy and radiation therapy as well as other types of tumors.
When To Call a Professional
If you experience any of symptoms of lung cancer, make an appointment to see your health care professional as soon as possible.
Prognosis
Squamous cell lung cancer usually is diagnosed after the disease has spread. The overall prognosis for squamous cell lung cancer and other non-small cell lung cancers is poor, with a 5-year survival rate of about 16%. The survival rate is higher (closer to 50%) when cancers are detected and treated early. The 5-year survival rate after surgery is approximately 47% for those with stage I disease. For those with more advanced, stage III disease, the 5-year survival rate is approximately 8%.
Even when surgery and other therapies are initially successful, there is a high risk of cancer returning. This is because squamous cell lung cancer and other non-small cell lung cancers readily spread to other parts of the body. Some recent exciting scientific discoveries about the mechanisms by which lung cancer grows may lead to better prognosis in the near future. Scientists are now able to understand the specific "signals" that a lung cancer cell receives that tells it to grow. By understanding these signals, some new types of drugs have been developed that may interfere or neutralize the signal. Thus, there are signals that tell the cancer cells to grow which can now be shut off, thus blocking the instructions to the cancer cells to grow.
Although the overall outcomes for patients with lung cancer are poor, this will hopefully change in the years to come as the understanding of cancer biology improves. In the meantime, the best single method to decrease the burden of lung cancer is to avoid ever smoking or stop immediately if you already smoke.
Additional Info
National Cancer Institute (NCI) U.S. National Institutes of Health Public Inquiries Office Building 31, Room 10A03 31 Center Drive, MSC 8322 Bethesda, MD 20892-2580 Phone: 301-435-3848 Toll-Free: 1-800-422-6237 TTY: 1-800-332-8615 E-Mail: cancergovstaff@mail.nih.gov //www.nci.nih.gov/
American Cancer Society (ACS) 1599 Clifton Road, NE Atlanta, GA 30329-4251 Toll-Free: 1-800-227-2345 //www.cancer.org/
American Lung Association 61 Broadway, 6th Floor New York, NY 10006br />Phone: (212) 315-8700 Toll-Free: (800) 548-8252E-Mail: info@lungusa.org //www.lungusa.org/
National Heart, Lung, and Blood Institute (NHLBI) P.O. Box 30105 Bethesda, MD 20824-0105 Phone: (301) 592-8573 TTY: (240) 629-3255 Fax: (301) 592-8563 E-Mail: nhlbiinfo@rover.nhlbi.nih.gov //www.nhlbi.nih.gov/
U.S. Environmental Protection Agency (EPA) Ariel Rios Building 1200 Pennsylvania Ave., N.W. Washington, DC 20460 Phone: 202-272-0167 //www.epa.gov/
U.S. Department of Labor's Occupational Safety & Health Administration (OSHA) 200 Constitution Ave. Washington, D.C. 20210 Phone: 202-693-1999 Toll-Free: 1-800-321-6742 TTY: 877-889-5627 //www.osha.gov/
ฝากข้อความหลังไมค์
Rss Feed
ผู้ติดตามบล็อก : 84 คน [
