In terms of deaths caused by various forms of cancer, lung cancer ranks second only to Breast Cancer. The National Cancer Institute recently reported that an estimated 172,570 new cases of lung cancer will be reported this year and that 163,510 American will die from this disease.
Lung cancer is caused predominantly by smoking. One expert says that in the case of Small Cell Lung Carcinoma (cancer), it is almost always caused by smoking.
Lung cancer is called lung cancer because it begins in the lungs. The right lung has three sections, the left lung has two. Each section is called a lobe. Sometimes the term "bronchogenic cancer" is used to refer to lung cancer as most lung cancers begin in one of the two breathing tubes, the bronchi, in the lungs.
There are two major types of lung cancer. One is the Small Cell Lung Cancer (SCLC) mentioned in the previous paragraph. The other is Non-Small Cell Lung Cancer (NSCLC).
Non-Small Cell Lung Cancer has three subtypes: Adenocarcinoma, Squamous Cell Carcinoma and Large Cell Undifferentiated Carcinoma. NSCLC is the least "serious" of the two types. In fact, if it is detected early, it is possible that it can be cured with surgery.
Andenocarcinoma accounts for about 40 percent of lung cancer cases in the U.S. It is the most common cancer among women and can be seen in non-smokers. Squamous Cell Carcinoma represents about 30 to 35 percent of lung cancers and tends to stay localized in the chest longer than other types of lung cancer. Large Cell Undifferentiated Carcinoma represents only about five to 15 percent of lung cancers in the U.S. The incidence of this type of cancer seems to be decreasing.
The worst and most aggressive form of lung cancer is Small Cell Lung Cancer. It represents only about 15 to 20 percent of all lung cancers. It spreads to the lymph nodes and other organs more quickly than NSCLC, but seems more responsive to chemotherapy drugs.
Non-Small Cell Lung Cancer is described in stages - Stage I through IV. WebMD recently reports survival rates of NSCLC as:
Stage 1A or 1B with no lymph node involvement has a five-year survival rate of 43 to 64 percent when treated with surgery.
Stage IIA or IIB with a single lymph node involvement, when treated with surgery, has a five-year survival rate of 20 to 40 percent.
Stage IIIA with a single lymph node involvement in the center of the chest, when treated with surgery has a five-year survival rate of 15 to 25 percent.
Stage IIIB with lymph node involvement in the chest and neck, when treated with radiation without other treatment, has a five-year survival rate of five to seven percent.
Stage IIIB with lymph node involvement in the chest and neck, when treated with radiation and chemotherapy, has a five-year survival rate between seven and 17 percent.转载请著名来自:(http://www.tTxYY.com 全免费英语学习网)
Stage IV with extensive lymph node involvement or cancer that has spread to other organs, hen treated with chemotherapy and palliative care to reduce symptoms and increase comfort has a one-year survival rate.
The prognosis is much bleaker for patients with Small Cell Lung Cancer. This form of cancer is found in two stages: limited or extensive. The limited version is that which is found in only one lung and nearby lymph nodes. The extensive type has spread outside the lung to other parts of the chest or body (metastasized). Limited SCLC when treated with chemotherapy and radiation therapy has an average survival time of 18 to 20 months. The extensive form of SCLC when treated with chemotherapy has a survival time of 10 to 12 months. Ttwo-year survival rate is one to three percent, and the five-year survival rate less than two percent.
The majority of people diagnosed with SCLC will die despite the best available treatment.
While surgery plays the most important part in the treatment of Non-Small Cell Lung Cancer, chemotherapy is always the chosen treatment for Small Cell Lung Cancer. In the case of limited stage SCLC, radiation therapy may also be used as the cancer is still localized to the chest area where radiation can be focused.
Small Cell Cancer Cells are so small they cannot be seen on scans. Even in the case of limited stage SCLC, it is possible for some cells to break away from the primary cancer and migrate to anywhere in the body. For this reason, chemotherapy is the preferred treatment as it treats the whole body, unlike radiation therapy which must be focused on a selected area. In act, chemotherapy is the preferred treatment for both limited and extensive stage Small Cell Lung Cancer.