I Think We Need A Breadth of Fresh AirDocument Transcript
1 Lung CancerBy: Peter Noone and Jaquella Howard Topics in Medicine and Biology Wilson Kwok Summer Ventures 2006
2Abstract If cells grow uncontrollably anywhere in the body, this is called a tumor. If thistumor is in the lungs, it is called lung cancer. Lung cancer has many causes, the main onebeing smoking. It also has many symptoms that make it easier to diagnose. Some of thesesymptoms could be many things besides lung cancer, such as a shortness of breath or lossof appetite. Someone may not even think of lung cancer as a possibility whenexperiencing these symptoms. The most common form of diagnosis is a chest x-ray,which will show the contents of the lungs, and show the doctor if there is a tumor.Sometimes the tumors can be very hard to detect, however, because it could be in earlystages of development. There are also numerous forms of treatments. The most commontreatments are chemotherapy, and radiotherapy, but there are others that could be used forspecific forms of the cancer.What is it? Lung cancer is the presence of a malignant tumor in the lungs. A tumor is theuncontrolled growth of mutated cells in a specific part of the body, in this case, in thelungs. A malignant tumor is a tumor that has the ability to spread to other parts of thebody, therefore making it very dangerous and deadly. There can sometimes be a tumorpresent in both the right and left lung, and other times there will be a tumor in only one ofthe lungs. Most often it is a bronchogenic carcinoma (90% of the time). Lung cancercauses about 3 million deaths worldwide every year, making it the most deadly cancer. Itused to occur more in men, however occurrence and death in men is beginning todecrease, and it is continually increasing in women. A woman that smokes is one and ahalf times more likely to develop lung cancer than a man with the same smoking habits.
3Lung cancer is also more common in African American men and women than in whitemen and women. There are two main types of lung cancer, non-small cell lung cancer, and small celllung cancer. Non-small cell cancer is much more common, and spreads much moreslowly than small cell cancer. There are three types of non-small cell cancer, whichaccount for over 80% of all cases of lung cancer. The three types of non-small cell lungcancer are Squamous Cell Carcinoma, which begins to grow in the lining of the respiratorytract, which is mad up of thin, flat cells; Adenocarcinoma, which originates in the lining of thelung itself; and Large cell carcinoma, which forms tumors that look abnormally large whenobserved through a microscope. Here is a picture of a normal lung next to a cancerous lung. There is quite an obvious difference. The normal lung is a brown color, while the cancerous one is black and red. Thisillustrates how much of a negative affect the tumor had on the lungs. It is easy to see how the cancer can cause difficulty breathing, due to the distorted shape of the lung, as well as theobstruction that is the tumor. One can also see the extra red color, which causes the coughing of blood.Prognosis The average 5-year survival rate for lung cancer is 15 percent, while other cancers,such as prostate cancer, have much higher rates (the 5-year survival rate for prostate canceris 99 percent). If the cancer is diagnosed while it is localized (the tumor has not yet spread to
4distant parts of the body) the 5-year survival rate is much better, at 49 percent. However,only 16 percent of the cases are diagnosed this early. If the cancer is detected after it isspread, the 5-year survival rate is a mere 2 percent.Causes The main cause of lung cancer, by far, is smoking. Roughly 87 percent of the cases oflung cancer in the United States are due to the effects of smoking. Smoking accounts forabout one third of all cancers, not limited to lung cancer, though lung cancer is the cancer thatis linked most closely to smoking. Cigarettes have over 4000 chemicals, many of which havebeen identified as cancer-causing. These chemicals can irritate cells in the lungs, andeventually turn them into cancer cells, which then reproduce uncontrollably, and form atumor. Cigarettes isn’t the only tobacco product that causes cancer, in fact, any tobaccoproduct is hazardous to your health. This is because all of them contain the same carcinogenicsubstances that cigarettes do. The main chemicals that cause lung cancer in tobacco are the following: • Acetylene • Ammonia • Arsenic • Carbon monoxide • Cyanide • Formaldehyde • Methanol • Nitrogen oxide • Nicotine The risk of getting lung cancer is directly related with your smoking habits. The risk increases with the following factors: • How many cigarettes a day you smoke. • How deeply you inhale
5 • How much of the cigarette you smoke • How long you have smoked Your risk decreases significantly when you quit smoking. Twenty years after you quit smoking your risk for lung cancer will be down to that of a non-smoker. Another leading cause of lung cancer is exposure to radon gas. Radon is a naturally occurring gas that is found in rocks and soil, but can also be found in the home. Because it is found in rocks, people that work in mines can often be susceptible to lung cancer. Passive smoking is also known to cause lung cancer in some people. Passive smoking is the act of breathing in someone else’s smoke (from cigarettes). In doing this, one exposes his or her lungs to the same risks that come in smoking. Although the exposure to smoke from passive smoking is small compared to that of a smoker, the risk is still present. This is especially true if you have a family member that smokes around you. This significantly increases your risk of developing lung cancer, because of the increased exposure to their smoke. The last major cause of lung cancer is exposure to asbestos. Asbestos is a mineral made up of many tiny fibers. When it is disturbed, the fibers form a dust. This dust can be inhaled, and can remain in the lungs for decades. There is also a higher risk for people to develop lung cancer if their family has ahistory of lung cancer.Symptoms There are many symptoms associated with lung cancer. They range from mild andharmless to painful and dangerous. The following symptoms are the most common ones thatpeople experience with lung cancer: • Shortness of breath • Coughing up blood • Incessant cough
6 • Wheezing • Chest or abdominal pain • Weight loss (loss of appetite) • Hoarse voice • Clubbing of the finger nails (slightly less common than others) • Difficulty swallowing Sometimes the cancer can also grow into the airway, which can cause breathingdifficulty, and, as mentioned before, wheezing. The cancer can also have a very abundantblood supply. Because the cancer has a weak surface, it can be ruptured, and this can causeblood to flow into the airway, which can subsequently be coughed up.Diagnosis There are a number of different ways lung cancer can be diagnosed. The doctor canperform a simple physical exam. This will not prove that the patient has cancer, but it will givethe doctor an idea, and the patient will receive further tests. Another method is the chest x-ray, which shows the contents of the lungs, and whether or not a tumor rsides in either lung.The tumors can sometimes be in the early stages of growth, and can be difficult to detect, sodoctors can sometimes overlook them. The last major form of diagnosis is a biopsy, which cancome in multiple forms itself. These variants are a bronchoscopy, a needle biopsy, andsurgery.
7 Here is a cross-section x-ray of a normal lung, with no visible presence of a tumor. Here is another cross-section of the same lung two years later. There is clearly anobstruction in the right hand side of the lung. A doctor would probably recognize this as a tumor in the early stages of development.
8 Here is another cross-section x-ray of the same lung, in an x-ray taken two years later. The then-small tumor has become a massive one in the right lung. This tumor would be virtually untreatable, and the patient would probably die.Treatment There are a number of different treatments for lung cancer: Surgery If the cancer hasn’t spread to both lungs, or to other parts of the body, surgery is a viable option for treatment. There are multiple procedures to remove the tumor: o Lobectomy: The removal of one lobe o Bilobectomy: The removal of two lobes o Pneumonectomy: The removal of an entire lung If the surgery is a success, the prognosis for the patient is relatively good. The 5- year prognosis is 70%.
9SurgeriesSegmental resection Segmental resection is the removal one or more segments of a lobe of a lung. As with lobectomy, the tissue removal is guided by anatomical planes, but in this procedure, the dissection is much more extensive. This procedure is often done in patients with borderline pulmonary function in order to preserve as much lung tissue as possible. Segmental resection is typically performed to remove a bleb, localized abscess, or small tumor. Because of the complexity of this surgery, patients are more likely to have air leaks through the chest tube (s) postoperatively and may have delayed re-expansion of the remaining lung tissue on the surgical side. Therefore, careful attention to postoperative pain control and respiratory care to reduce the risk of atelectasis or nosocomial pneumonia is particularly important. One or two chest tubes may be in place after the procedure. Watch for intermittent bubbling in the water seal chamber which can indicate a persistent air leak along the suture line on the lung. (Description of surgery from Clinical Update for the Professional Nurse) Description: A Segmental resection(http://www.lungcancerinfo.net/images/treatment_lung.jpg)
10Wedge resection Wedge resection is the removal a small, triangular piece of lung tissue near the lung surface. This procedure is typically done for lung biopsy or to remove a small, well-defined lesion. Usually a single postoperative chest tube is in place to allow air to escape from the pleural space. Postoperative bleeding is typically minimal. . (Description of surgery from Clinical Update for the Professional Nurse)Lobectomy Lobectomy is the removal of one lobe of one lung is a relatively straightforward surgical procedure because the demarcation along anatomical borders is clear. This procedure is typically chosen when a lesion is clearly limited to one lobe of one lung — a tumor, cyst, abscess, traumatic injury, or bronchiectasis. Expect one or two chest tubes postoperatively to drain both air and fluid from the chest. . (Description of surgery from Clinical Update for the Professional Nurse)Pneumonectomy Pneumonectomy is the removal of an entire lung, most commonly to treat lung cancer. . (Description of surgery from Clinical Update for the Professional Nurse)Lung volume reduction Lung volume reduction is a procedure designed to treat emphysema, currently under study in a number of select centers across the United States. Removing sections of hyper-inflated lung tissue may reduce dyspnea and improve lung
11 function in patients with advanced emphysema. Outcomes have been variable and seem to depend largely on initial patient selection. Chest tubes are required postoperatively; postop air leaks resulting from sutures or staples placed in friable lung tissue can be particularly difficult to manage. . (Description of surgery from Clinical Update for the Professional Nurse)Thoracoplasty Thoracoplasty is not technically lung surgery — it is a procedure done on the chestwall in which one or more ribs or rib segments are removed to reduce the size of thethorax. This procedure is rarely done today, but we may care for patients who underwentthis procedure in the 1950s when it was a common treatment for chronic tuberculosis. Chemotherapy Chemotherapy is used mainly for small-cell lung cancer, because there is a good response to this treatment with small-cell lung cancer. Chemotherapy is the use of special anti-cancer drugs, also known as “cytoxic” drugs to destroy existing cancer cells. Chemotherapy is a global treatment. This means that the drugs can treat the whole body, whereas other forms of treatments are local, meaning they only treat one part of the body. Having a global treatment is important because it is likely that the cancer cells will have spread to other parts of the body unbeknownst to the patient or doctor.
12 Description: Chemotherapy pills http://www3.mdanderson.org/depts/hcc/fall99/images/pills.gifRadiotherapy Radiotherapy is the use of high-energy rays to kill cancer cells. It is sometimesused alongside other treatments, most often chemotherapy. Radiotherapy can be usedto shrink a tumor, which will later be removed by surgery. Radiotherapy works by bombarding cancerous cells with rays that disrupt itsduplication. It partially disables the cancerous cells from duplicating at their normalrate, and makes DNA replication difficult. Because of this, radiotherapy has manyunpleasant side effects, such as hair loss, and skin disorders. This is because these areparts of the body that also reproduce very often, and the radiotherapy disrupts them asit does the cancer cells.Photodynamic Therapy This type of treatment can be used when the patient’s tumor is inoperable. Thefirst stage of this treatment is the injection of a drug that is triggered by light, such aslumin. Then, a bronchoscopy is performed. A bronchoscopy is the insertion of ascope that is used to examine the airwaves. When the scope is near the tumor, it emits
13 light of a specific wavelength. This then sensitizes the tumor, and a laser is then directed toward the tissue, and destroys it. Electrosurgery Electrosurgery is the use of a disk, bulb, or needle to direct electrical energy at the cancerous cells to destroy them.Internal Radiation Therapy The radiation is swallowed, injected, or implanted directly into the tumor inside thebody as close to the cancer as possible. These substances that produce radiation are calledradioisotopes. Internal radiation gives you a high dose of radiation in a shorter time thanwith external radiation. Some internal radiation is permanent and some are temporary. Insome cases, both internal and external are used.External Radiation Therapy An example of External Radiation Therapy would be External Beam RadiationTherapy (EBT). It is a method that delivers a beam of high-energy x-rays to the locationof the tumor. These x-rays can destroy all of the cancer cells. Description: External Radiation Therapy http://www.radiologyinfo.org/en/photocat/photos_pc.cfm?Image=astro20.jpg&pg=ebt&bhcp=1
14Cryosurgery It is the use of extreme cold made by liquid nitrogen to destroy the abnormal tissue.For external tumors liquid nitrogen is applied directly to the tumor with a cotton wipe orspray. For internal tumors liquid nitrogen is circulated throughout the body with a hollowinstrument called a cryoprobe. The doctor uses a MRI or ultrasound to guide thecryoprobe in its freezing process. After cryosurgery is performed on external tumors itdissolves and forms a scab. After cryosurgery is performed on internal tumors it thawsand is absorbed into the body.Stages Doctors will decide what treatment to give you based on the stage the tumor is atin the lung. These stages take into account whether or not the cancer has spread to otherparts of the body, the physical size of the cancer, and whether or not the lymph nodes areaffected. The following table shows how the stage of the cancer is derived. Stage Tumor Spread to Spread to Size/invasion of Lymph Node body lung 1a T1 No no 1b T2 No No 2a T1 Some No 2b T2 Some No 3a T1-3 Some No 3b T4 severe No
15 4 Any metastasis (spread through body) *T=Tumor size (t1 is less than 3cm. t2 is greater than 3 cm), and tumor site (t3 is invasion of chest wall, pleura, etc., T4 is invasion of mediastinum) The treatment received is based on the stages described above. Stages 1a/b and 2a/b are both treated with surgery, because the tumor is localized, and removable. Stage 3a is treated with chemotherapy, followed up by radiotherapy or surgery. Stage 3b is treated with a combination of chemotherapy and radiation therapy. Stage 4 is treated with chemotherapy. The chances of survival if the cancer reaches stage four are miniscule.Conclusion Lung cancer can be treated through surgery, electrosurgery radiotherapy, chemotherapy, internal and external therapy, photodynamic therapy, and cryosurgery. Lung cancer patients have many options for treatments, but recovery depends on each individual. Lung cancer can be beaten if the individual is willing to work to survive.
16 BIBILIOGRAPHY1. Wart, P. (July 09, 2006). Smoking Causes Cancer. Retrieved July 9, 2006, from Health Plus Web site: http://vanderbiltowc.wellsource.com/dh/Content.asp?ID=13252. Lung cancer. (2006, July 7). In Wikipedia, The Free Encyclopedia. Retrieved, July 10,2006, from http://en.wikipedia.org/w/index.php?title=Lung_cancer&oldid=62543390.3. (2005, August). Lung Cancer. Retrieved July 10, 2006, from HealthTalk Web site: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Cancer_and_asbestos?OpenDocument4. Clinical Update, September 1999http://www.atriummed.com/Products/Chest_Drains/clinical%20updates/ClinicalUpdateSept99.pdf#search=How%20is%20the%20surgery%20Segmental%20or%20Wedge%20Resection%20of%20the%20lung%20done%3F‘5. Radiology Info- Lung Cancer, July 11, 2005http://www.radiologyinfo.org/en/info.cfm?pg=lungcancer&bhcp=16. Hong Kong Observatory, 21 Sep 20057. http://www.weather.gov.hk/radiation/tidbit/200509/man_made_4e.htm
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