Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
Lung cancer is the number-one cause of cancer deaths
in both men and women in the U.S. and worldwide.
Cigarette smoking is the principal risk factor for
development of lung cancer.
Passive exposure to tobacco smoke also can cause
The two types of lung cancer, which grow and spread
differently, are the small cell lung cancers (SCLC) and non-small cell lung
The stage of lung cancer refers to the extent to which
the cancer has spread in the body.
Treatment of lung cancer can involve a combination of
surgery, chemotherapy, and radiation therapy as well as newer experimental
The general prognosis of lung cancer is poor, with
overall survival rates of about 16% at five years.
Smoking cessation is the most important measure that can prevent the
development of lung cancer.
What is lung cancer?
Cancer of the lung, like all cancers, results from an abnormality in the body's
basic unit of life, the cell. Normally, the body maintains a system of checks
and balances on cell growth so that cells divide to produce new cells only when
new cells are
needed. Disruption of this system of checks and balances on cell growth results
in an uncontrolled division and proliferation of cells that eventually forms a
mass known as a tumor.
Tumors can be benign or malignant; when we speak of "cancer," we are referring
to those tumors that are malignant. Benign tumors usually can be removed and do
not spread to other parts of the body. Malignant tumors, on the other hand, grow
aggressively and invade other tissues of the body, allowing entry of tumor cells
into the bloodstream or lymphatic system and then to other sites in the body.
This process of spread is termed metastasis; the areas of tumor growth at these
distant sites are called metastases. Since lung cancer tends to spread or
metastasize very early after it forms, it is a very life-threatening cancer and
one of the most difficult cancers to treat. While lung cancer can spread to any
organ in the body, certain organs -- particularly the adrenal glands, liver,
brain, and bone -- are the most common sites for lung cancer metastasis.
The lung also is a very common site for metastasis from tumors in other parts
of the body. Tumor metastases are made up of the same type of cells as the
original (primary) tumor. For example, if prostate cancer spreads via the
bloodstream to the lungs, it is metastatic prostate cancer in the lung and is
not lung cancer.
The principal function of the lungs is to exchange gases between the air we breathe and the blood. Through the lung, carbon dioxide is removed from the bloodstream and oxygen from inspired air enters the bloodstream. The right lung has three lobes, while the left lung is divided into two lobes and a small structure called the lingula that is the equivalent of the middle lobe on the right. The major airways entering the lungs are the bronchi, which arise from the trachea. The bronchi branch into progressively smaller airways called bronchioles that end in tiny sacs known as alveoli where gas exchange occurs. The lungs and chest wall are covered with a thin layer of tissue called the pleura.
Lung cancer picture
Lung cancers can arise in any part of the lung, but 90%-95% of cancers of the lung are thought to arise from the epithelial cells, the cells lining the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic cancers or bronchogenic carcinomas. (Carcinoma is another term for cancer.) Cancers also can arise from the pleura (called mesotheliomas) or rarely from supporting tissues within the lungs, for example, the blood vessels.
When lung cancer first develops, there may be no symptoms at all. But as the cancer grows, it can cause changes that people should watch for. Common signs and symptoms of lung cancer include:
a cough that doesn't go away and gets worse over time
constant chest pain
coughing up blood
shortness of breath, wheezing, or hoarseness
repeated problems with pneumonia or bronchitis
swelling of the neck and face
loss of appetite or weight loss
These symptoms may be caused by lung cancer or by other conditions. It is important to check with a doctor if you have symptoms because only a doctor can make a diagnosis. Don't wait to feel pain. Early cancer usually doesn't cause pain.