ABSTRACT – Lung Cancer causes cancerous cells to divide uncontrollably and form a tumor in lungs which leads to...
Lung Cancer is a type of cancer that begins in the lungs. Your lungs are two spongy organs in your chest that take in oxygen when you inhale and release carbon dioxide when you exhale.
It is the leading cause of cancer deaths in the United States, among both men and women. It claims more lives each year than do colon, prostate, ovarian and breast cancers combined.
People who smoke have the greatest risk of this disease, though this cancer can also occur in people who have never smoked. The risk of this cancer increases with the length of time and number of cigarettes you’ve smoked. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing this cancer.
It typically doesn’t cause signs and symptoms in its earliest stages. Signs and symptoms of this cancer typically occur only when the disease is advanced.
Signs and symptoms of may include:
A new cough that doesn’t go away
Coughing up blood, even a small amount
Shortness of breath
Losing weight without trying
Smoking causes the majority of cancers — both in smokers and in people exposed to secondhand smoke. But this cancer also occurs in people who never smoked and in those who never had prolonged exposure to secondhand smoke. In these cases, there may be no clear cause of this cancer.
How smoking causes this cancer
Doctors believe smoking causes cancer by damaging the cells that line the lungs. When you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately.
At first your body may be able to repair this damage. But with each repeated exposure, normal cells that line your lungs are increasingly damaged. Over time, the damage causes cells to act abnormally and eventually cancer may develop.
Types of this cancer
Doctors divide cancer into two major types based on the appearance of lung cancer cells under the microscope. Your doctor makes treatment decisions based on which major type of cancer you have.
The two general types include:
Small cell- Small cell lung cancer occurs almost exclusively in heavy smokers and is less common than non-small cell cancer.
Non-small cell- Non-small cell lung cancer is an umbrella term for several types of cancers that behave in a similar way. Non-small cell cancers include squamous cell carcinoma, adenocarcinoma and large cell carcinoma.
A number of factors may increase your risk of lung cancer. Some risk factors can be controlled, for instance, by quitting smoking. And other factors can’t be controlled, such as your family history.
Risk factors for lung cancer include:
Smoking. Your risk of lung cancer increases with the number of cigarettes you smoke each day and the number of years you have smoked. Quitting at any age can significantly lower your risk of developing lung cancer.
Exposure to secondhand smoke. Even if you don’t smoke, your risk of lung cancer increases if you’re exposed to secondhand smoke.
Exposure to radon gas. Radon is produced by the natural breakdown of uranium in soil, rock and water that eventually becomes part of the air you breathe. Unsafe levels of radon can accumulate in any building, including homes.
Exposure to asbestos and other carcinogens. Workplace exposure to asbestos and other substances known to cause cancer — such as arsenic, chromium and nickel — also can increase your risk of developing lung cancer, especially if you’re a smoker.
Family history of lung cancer. People with a parent, sibling or child with lung cancer have an increased risk of the disease.
Treatment for lung cancer primarily involves surgical removal of the cancer, chemotherapy, or radiation therapy, as well as combinations of these treatments. Targeted therapies and immunotherapy treatments are becoming more common, as well. The decision about which treatments will be appropriate for a given individual must take into account the location and extent of the tumor, as well as the overall health status of the patient.
As with other cancers, doctors may prescribe therapy intended to be curative (removal or eradication of a cancer) or palliative (measures that are unable to cure a cancer but can reduce pain and suffering). Doctors may prescribe more than one type of therapy. In such cases, the therapy that is added to enhance the effects of the primary therapy is referred to as adjuvant therapy. An example of adjuvant therapy is chemotherapy or radiotherapy administered after surgical removal of a tumor in an attempt to kill any tumor cells that remain following surgery.
Surgery: Doctors generally perform surgical removal of the tumor for limited-stage (stage I or sometimes stage II) NSCLC and is the treatment of choice for cancer that has not spread beyond the lung. About 10%-35% of lung cancers can be removed surgically, but removal does not always result in a cure, since the tumors may already have spread and can recur later. Among people who have an isolated, slow-growing lung cancer removed, 25%-40% are still alive five years after diagnosis. It is important to note that although a tumor may be anatomically suitable for resection, surgery may not be possible if the person has other serious conditions (such as severe heart or lung disease) that would limit their ability to survive an operation. Surgeons perform surgery less often with SCLC than with NSCLC because these tumors are less likely to be localized to one area that can be removed.
The surgical procedure chosen depends upon the size and location of the tumor. Surgeons must open the chest wall and may perform a wedge resection of the lung (removal of a portion of one lobe), a lobectomy (removal of one lobe), or a pneumonectomy (removal of an entire lung). Sometimes lymph nodes in the region of the lungs also are removed (lymphadenectomy). Surgery for lung cancer is a major surgical procedure that requires general anesthesia, hospitalization, and follow-up care for weeks to months. The risks of surgery include complications due to bleeding, infection, and complications of general anesthesia.