Page 4
molecules that predict cancer could allow screening that would lead to early diagnoses and saved lives. Refinements of viewing and sampling cells of the bronchi and lung are providing improved and less invasive diagnostic techniques. New bronchoscopic technologies using ultrasound and electromagnetic navigation may improve the chance of making a correct diagnosis when the cancer is confined to a small area of the lung. The importance of this is underscored because a small lung cancer diagnosed early is more likely to be able to be completely surgically removed and has a better chance of cure. Identifying genetic predisposition to lung cancer could increase the accuracy and efficacy of screening. Genetic predisposition to lung cancer may be related to variations within genes that are associated with controlling the growth cycle of the cell, its metabolism of carcinogens, and DNA repair. The search for markers explores genes differentially expressed in patients with lung cancer compared to those without. Gene expression profiling on bronchial cells suggests that such biomarkers may predict lung cancer risk. In the future, molecular approaches will likely allow selection of patients who are most likely to benefit from specific therapies, and will guide the development of more effective therapeutic agents. The potential for research in this area is enormous, as these approaches should also improve the ability to predict individual patient outcomes. Lung cancer staging is defined by clinical outcomes and, at present, is based solely on anatomic factors—the size of the tumor and where it has spread. Accurate staging is the basis for predicting survival and is key to clinical trials that compare treatments among homogeneous populations of patients. For example, patients with Stage I non-small cell lung cancer treated with surgical resection have a five-year survival of about 73 percent (6). Considering these are early stage patients, this five-year survival is lower than expected; clearly some patients do poorly despite surgery. If those patients could be identified, further treatment would be given to try to improve their survival. Current genetic research has identified several genes that may predict outcomes for patients. Genes linked to lung cancer, and in particular to poor survival, are being systematically cataloged. Further study should clarify which genes and Whitebook_breathing_Ch11.indd 118 6/28/10 8:48:28 PM Chapter 11 Lung Cancer 119 gene products will predict patient outcomes. This may help identify individuals who would benefit from more aggressive treatment, and which genes might be targets for new therapies. All of these investigative efforts will enhance our understanding of the molecular mechanisms governing carcinogenesis and tumor behavior. Translation of this knowledge to the development of biomarkers predicting risk, clinical models that can more accurately predict patient outcomes, and novel therapies targeted to molecular pathways of carcinogenesis will facilitate the goal of personalized treatment for individual patients with lung cancer. What is lung cancer? Lung cancer begins when cells in the lung grow out of control and form a mass called a tumor, lesion, or nodule. There are 2 major types of lung cancer: non-small cell and small cell. They are usually treated in different ways. Lung cancer is the second most common cancer diagnosed in both men and women in the United States. What is the function of the lungs? The lungs are made up of 5 lobes, 3 in the right lung and 2 in the left lung. As a person inhales, the lungs absorb oxygen from the air, which is delivered to the rest of the body through the bloodstream. When the body uses the oxygen, carbon dioxide is created. It is carried back to the lungs through the bloodstream and released when a person exhales. What does stage mean? The stage is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting other parts of the body. There are 5 stages for lung cancer: stage 0 (zero) and stages I through IV (1 through 4). Small cell lung cancer is primarily classified as either limited stage or extensive stage depending on where it has grown and spread. Find more descriptions and illustrations of