2010 Lung Cancer Study
The following cancer site analysis by Mary Koshy, MD, on lung cancer includes statistical comparisons for patients diagnosed at MMH. Unless stated otherwise, the statistical graphs and tables found in this study include only analytic cases.
Lung cancer is the leading cause of cancer deaths in women and men in the United States and throughout the world. Lung cancer has surpassed breast cancer as the leading cause of cancer deaths in women. In the United States in 2009, 159,390 people were projected to die from lung cancer, which is more than the number of deaths from colon and rectal, breast, and prostate cancer combined. Only about 2% of patients diagnosed with lung cancer that has spread to other areas of the body are still alive five years after the diagnosis, although the survival rates for lung cancers diagnosed at the earliest stage are higher, with approximately 49% surviving for five years or longer. Cancer occurs when normal cells undergo a transformation that causes them to grow and multiply without control. The cells form a mass or tumor that differs from the surrounding tissues from which it arises. Tumors are dangerous because they take oxygen, nutrients and space from healthy cells and because they invade and destroy or reduce the ability of normal tissues to function.
Most lung tumors are malignant. This means that they invade and destroy the healthy tissues around them and can spread throughout the body.
- The tumors can spread to nearby lymph nodes or through the bloodstream to other organs. This process is called metastasis.
- When lung cancer metastasizes, the tumor in the lung is called the primary tumor, and the tumors in other parts of the body are called secondary tumors or metastatic tumors.
Some tumors in the lung are metastatic from cancers elsewhere in the body. The lungs are a common site for metastasis. If this is the case, the cancer is not considered to be lung cancer. For example, if prostate cancer spreads via the bloodstream to the lungs, it is metastatic prostate cancer (a secondary cancer) in the lung and is not called lung cancer.
About 90% of lung cancers arise due to tobacco use. The risk of developing lung cancer is related to the number of cigarettes smoked, the age at which a person started smoking, and how long a person has smoked (or had smoked before quitting). Other causes of lung cancer include secondhand smoke, air pollution, radon and asbestos.
Preventative Measures and Early Detection
Lung cancer remains a highly preventable disease because 90% of lung cancers occur in smokers or former smokers. The best way to prevent lung cancer is to avoid smoking.
Smokers who use a combination of supplemental nicotine, medical therapy, group therapy, and behavioral training show a significant decrease in smoking rates.
Currently, the American Cancer Society does not recommend routine chest X-ray screening for lung cancer. Periodic chest X-rays may be appropriate for current or former smokers. It is best to discuss the pros and cons of this approach with a healthcare provider. The U.S. Preventive Services Task Force (USPSTF) has determined that current evidence is insufficient to recommend for or against screening for lung cancer. This means that further research is needed to clarify whether screening tests for lung cancer are beneficial.
Lung cancers usually are divided into two main groups that account for about 95% of all cases.
- The division into groups is based on the type of cells that make up the cancer.
- The two main types of lung cancer are characterized by the cell size of the tumor when viewed under the microscope. They are called small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC includes several subtypes of tumors.
- SCLCs are less common, but they grow more quickly and are more likely to metastasize than NSCLCs. Often, SCLCs have already spread to other parts of the body when the cancer is diagnosed.
- About 5% of lung cancers are of rare cell types, including carcinoid tumor, lymphoma and others.
The specific types of primary lung cancers are as follows:
- Adenocarcinoma (an NSCLC) is the most common type of lung cancer, making up 30%-40% of all cases. A subtype of adenocarcinoma is called bronchoalveolar cell carcinoma, which creates a pneumonia-like appearance on chest X-rays.
- Squamous cell carcinoma (an NSCLC) is the second most common type of lung cancer, making up about 30% of all cases.
- Large cell cancer (another NSCLC) makes up 10% of all cases.
- SCLC makes up 20% of all cases.
The tumor node metastasis (TNM) staging system for non-small cell lung cancer (NSCLC) categorizes tumors on the basis of primary tumor characteristics (T), the presence or absence of regional lymph node involvement (N), and the presence or absence of distant metastases (M). The overall stage of the tumor (stage I through IV) is determined by the combination of T, N and M grades. The 7th edition of the TNM staging system is the most recent version. It was developed by the International Association for the Study of Lung Cancer (IASLC) and approved by the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC) for use beginning January 1, 2010. It replaces the 6th edition of the TNM staging system, which was used prior to January 2010.
In 2009, 19% of newly diagnosed MMH lung cancer patients were Stage I, only 2% were Stage II, 24% were Stage III and 29% were diagnosed with Stage IV disease.
Treatment decisions in lung cancer depend on whether the histology is SCLC or NSCLC. Treatment also depends on tumor stage and a patient's general physical condition (the ability to withstand treatment procedures).
- Surgery is the preferred treatment for patients with early stage NSCLC (Stage I or II). If surgery is not an option, radiation therapy with or without chemotherapy is often recommended.
- In Stage III NSCLC, patients may be offered chest radiation treatment combined with chemotherapy. Surgical resection may be recommended to patients with very limited stage IIIA disease and is not recommended for stage IIIB tumors.
- For patients with Stage IV NSCLC, chemotherapy is the main treatment option. Radiation therapy may be recommended as well and targeted to areas that cause pain or other problems.
- For patients with limited-stage small cell lung cancer, treatment usually involves a combination of chemotherapy and chest radiation therapy. Surgery is not a treatment option except in rare cases during the very early stages of the disease. Patients may also be offered brain radiation treatment to prevent the spread of cancer in that region.
- For patients with extensive-stage small cell lung cancer, chemotherapy is the most important treatment option. Targeted radiation therapy may be recommended for areas that cause pain or other problems. Most patients also are offered brain radiation treatment.
Survival is most dependent on stage of the lung cancer at diagnosis. If the lung cancer is detected before it has had a chance to spread to other organs, and if it is treated appropriately, at least 49% of patients can survive five years or longer after the initial diagnosis. Only 15% of lung cancers, however, are found at this early stage. According to the National Cancer Institute's Survival, Epidemiology and End Results (SEER) Database, for all histologies the overall 5-year relative survival for 1999-2006 from 17 geographic areas was 15.8%. Five-year relative survival by race and sex was 13.8% for white men, 18.6% for white women, 11.3% for black men and 14.4% for black women. In the majority of patients for whom cure is not possible, survival may vary from months to years, depending on the extent of the cancer, the overall condition of the patient, and his/her response to treatment and the duration of that response.
Lung cancer continues to be the leading cause of cancer death in both men and women in our country. We must continue to focus our efforts on the diagnosis, treatment and prevention of this deadly disease. In addition, the elimination of tobacco products and avoiding exposure to secondhand smoke must continue to be emphasized.
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