Lung cancer is among the leading causes of cancer-related deaths throughout the world. This alarming statistic is due to the fact that the diagnosis is often made in the advanced stages. Such is the insidious nature of the disease. There are several different types of lung cancer; however, they all have similar symptoms and prognosis.
Risk Factors
The most significant factor for the development of lung cancer is cigarette smoking. More than 80 percent of people with lung cancer are smokers, according to the medical textbook "Robbins Pathologic Basis of Disease." Other important risk factors include asbestos exposure and exposure to all types of radiation. Air pollution is also thought to be a minor risk factor.
Symptoms
The symptoms of lung cancer often do not manifest until very late in the disease process. The most common symptom is a chronic cough, which most smokers tend to have before cancer develops, and as such, the cough is ignored until the characteristics change. This is usually a dry cough but may progress to the production of significant amounts of sputum and even blood. People may also complain of significant weight loss, chest pain and shortness of breath with very mild exertion.
Tests
The first laboratory test that is done is a plain chest X-ray. The X-ray may or may not show a tumor in the lung even when the cancer is advanced. To confirm the diagnosis of suspected lung cancer, a special test called a bronchoscopy must be done. A telescopic instrument called a bronchoscope is used to visualize the tumor and to perform a biopsy. The tissue sample is then sent to the laboratory for analysis. To assess the extent of the disease and operability, a physician may order a computerized tomography, or CT, scan; magnetic resonance imaging, or MRI; or a positron emission tomography, or PET, scan.
Treatment
Treatment options are divided into surgery, chemotherapy and radiation therapy. Surgery is reserved for early stage disease and usually followed by chemotherapy and/or radiotherapy. Surgery may involve the removal of a lobe of the lung, multiple lobes or the entire lung, and surrounding lymph nodes. Chemotherapy and radiation therapy are often combined for treatment of advanced cancers, as there is no benefit in attempting surgery.
Prognosis
The prognosis is generally poor. Overall survival at five years for early stage cancer ranges from 40 percent to 55 percent, according to the medical textbook "Sabiston Textbook of Surgery." Survival rates for more advanced stages are significantly lower.
References
- "Sabiston Textbook of Surgery"; C.M. Townsend, et al.; 2001
- "Swartz Principles of Surgery"; S. Schwartz, et al.; 1999
- "Robbins Pathologic Basis of Disease"; R. Contran; et al.; 1999
