Biology 103
2003 Third Paper
On Serendip

Lung Cancer accounts for15 percent of all cancer cases, and an estimated 170,000
people in the United States get lung cancer a year. (5)About 155,000 of those people die from the cancer. Recently, the rate of women affected by lung cancer has increased, while the rate of men affected has decreased. However, lung cancer is the leading cancer that kills both women and men. (1) So, what is lung cancer? Lung cancer is the uncontrollable growth of abnormal cells in the lung. (5) There are two main types of lung cancer: non-small cell and small- cell lung cancer. Non-small cell lung cancer (or NSCLC) is more common than small-cell lung cancer (SCLC) and occurs in about 80% of all lung cancer cases. (3)

Early lung cancer does not cause symptoms, so when the symptoms finally do show and the cancer is detected, it is already at an advanced stage. (1) Smoking has been shown to be the primary cause of lung cancer. About 87% of all cases occur in people who smoke. (1) However, not everyone who smokes gets lung cancer and not everyone who gets lung cancer smokes. One of the main symptoms of lung cancer is a chronic cough that lasts for more than two weeks. Another is constant chest pain. Other symptoms include wheezing, shortness of breath, coughing blood, hoarseness, and repeated pneumonia or bronchitis. (1) There are also less noticeable signs such as unexplained fever, weight loss, or appetite loss. (2)

As mentioned earlier, there are two types of lung cancer: NSCLC and SCLC. NSCLC can be divided into three sections. First, there is epidermoid carcinoma which is usually starts in the large breathing tubes, and grows slowly. (5) There is also adenocarcinoma, which is found in the mucus glands and can vary in size and rate of growth. Finally, there is large cell carcinoma, which begins at the surface of the lung, and grows very rapidly. (5) SCLC, also known as oat cell carcinoma, has no divisions. It starts in the large breathing tubes, and grows fairly rapidly. This type of lung cancer is usually very large by the time it is diagnosed. (5)

There are also different stages of lung cancer. For NSCLC, there are four main stages. Stage I A/B is when the tumor has spread to the lymph nodes that are associated
with the lung. (2) Stage II A/B is when the tumor has spread to the lymph nodes in the tracheal area, including the chest wall and the diaphragm. Stage III A is when the tumor has spread to lymph nodes on the opposite lung or on the neck. Finally, Stage IV, the most severe stage, is when the tumor has spread beyond the chest. (2) On the other hand, SCLC only has two stages of cancer growth. Limited is when the tumor is only found in one lung and the nearby lymph nodes. Extensive is when the tumor has spread beyond the lung into other organs.

The treatments for lung cancer depend on the type, location, and size of the cancer. (3) One option is to remove the tumor through surgery; however, it depends on the location of the tumor. A surgeon can perform a resection, which is a removal of part of the lung. The removal of the entire lobe of the lung is called a lobectomy. (3) In addition, there is a surgery called a pneumonectomy, which removes the entire lung. Each kind of surgery is performed according to how advanced the cancer is and how much of the lung has been affected by the cancer. (3)

Another option for treatment is chemotherapy. Chemotherapy is the use of antidrugs to kill cancer cells or to control the growth of cancer cells in the body. It can also be used after surgery if any cancer cells remain. Usually, chemotherapy is administered by an injection through an IV or through a catheter. However, some antidrugs are administered through pills as well. (3) Chemotherapy can be used in advanced stages of cancer to relieve symptoms, and in all stages of SCLC. (1)

An alternative to chemotherapy is radiation. Radiation is the use of high-energy rays to kill cancer cells. However, they can only be directed towards a specific area and therefore only affect the cancer cells in that area. (3) Radiation treatments can be used before surgery to shrink the cancer cells or afterwards to get rid of any remaining cells. There are two types of radiation. External radiation is radiation that comes from a machine. (3) Internal radiation is when an implant of radioactive material is placed into or near the tumor. (3) Studies have shown that a combination of therapies can be more effective than just one treatment by itself.

Any person 60 years or older who has a history of smoking or is currently smoking should get tested for lung cancer. Screening tests are used to detect lung cancer early so that doctors may treat it before it spreads. One test is called the low-radiation dose spiral completed tomography scan, or low-dose CT scan.(2) Recent trials done in the U.S. and Japan have shown that this type of screening can lead to early detection of lung cancer in people with high-risk. They also found that this type of test worked significantly better than chest x-rays at detecting lung cancer. In the U.S., a study of 1,000 people who were at high-risk for lung cancer took the low-dose CT san. It exposed malignant tumors four times as often as chest x-rays and detected Stage I tumors six times as often. (2) Therefore, this type of screening is becoming more popular in patients with a high-risk for lung cancer.

New research studies are being done to test new drugs or combinations of drugs for lung cancer. Other clinical trials test the combination of chemotherapy and radiation treatments. (2) The newest breakouts in lung cancer treatment are usually discovered through clinical trials. Before the Drug and Food Administration can approve a new drug for treatment, it must go through a series of phases. Phase I Trials test how a drug should be administered to the patient, how often it should be administered, and in what dose. (4) These beginning trials only use a small group of patients for testing. Phase II Trials include the initial information about the effectiveness of the drug, and then can be used for testing to a specific type of lung cancer. Phase III Trials compare the effectiveness of the current drugs with the drug being tested. (4) These trials use a large number of patients from around the country. Each patient is randomly assigned a drug, either the new one or the standard one, and then the efficiency of each drug is tested against the other. The last stage in clinical trials is called Phase IV. These trials are used to continue testing the drug after it has been approved by the FDA and is already available on the market. (4)

Recently, the International Adjuvant Lung Cancer Trial (IALT) did a study comparing the effect of surgery to surgery combined with chemotherapy to treat NSCLC. The study included 1, 867 patients from 33 different countries. (4) Thirty-six percent of the people had Stage I lung cancer, twenty-five percent had Stage II, and thirty-nine percent had Stage III. They found that after two years, 61% of people who had combined treatment of surgery and chemotherapy were free of cancer, compared to the 55% of people who had just had surgery. (4) After five years, 39% of the people who had had adjuvant chemotherapy were cancer free, compared to the 34% of people who had had only surgery. (4) The discrepancy is small, but it is enough to help scientists evaluate which method of treatment will help the patient the most.

In conclusion, new studies are being done every day to improve the treatment of lung cancer. However, it is still a fatal illness that kills most people if it is not detected early. The main way to avoid lung cancer is to stop smoking! Cigarettes and tobacco have about 4,000 chemicals in them which lead directly to cancer. (1) The more a person smokes, the greater the possibility of lung cancer. However, if one stops smoking, the risk of getting lung cancer reduces each year. After ten years, the probability decreases to about one-half or one-third the risk of people who continue to smoke. (1) In addition, secondhand smoke causes about 3,000 people to die from lung cancer a year. (1)Therefore, the best way to prevent yourself or those around you from getting lung cancer is to stop smoking!

References

1)Facts About Lung Cancer

2) Lung Cancer.org

3) Treatment for Lung Cancer

4)ALCASE Education

5) What Is Lung Cancer?


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