Lung Cancer

By: Peter Noone and Jaquella Howard

Topics in Medicine and Biology

Wilson Kwok

Summer Ventures 2006

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Abstract

If cells grow uncontrollably anywhere in the body, this is called a tumor. If this

tumor is in the lungs, it is called lung cancer. Lung cancer has many causes, the main one

being smoking. It also has many symptoms that make it easier to diagnose. Some of these

symptoms could be many things besides lung cancer, such as a shortness of breath or loss

of appetite. Someone may not even think of lung cancer as a possibility when

experiencing 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 early

stages of development. There are also numerous forms of treatments. The most common

treatments are chemotherapy, and radiotherapy, but there are others that could be used for

specific forms of the cancer.

What is it?

Lung cancer is the presence of a malignant tumor in the lungs. A tumor is the

uncontrolled growth of mutated cells in a specific part of the body, in this case, in the

lungs. A malignant tumor is a tumor that has the ability to spread to other parts of the

body, therefore making it very dangerous and deadly. There can sometimes be a tumor

present in both the right and left lung, and other times there will be a tumor in only one of

the lungs. Most often it is a bronchogenic carcinoma (90% of the time). Lung cancer

causes about 3 million deaths worldwide every year, making it the most deadly cancer. It

used to occur more in men, however occurrence and death in men is beginning to

decrease, and it is continually increasing in women. A woman that smokes is one and a

half times more likely to develop lung cancer than a man with the same smoking habits.

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Lung cancer is also more common in African American men and women than in white

men and women.

There are two main types of lung cancer, non-small cell lung cancer, and small cell

lung cancer. Non-small cell cancer is much more common, and spreads much more

slowly than small cell cancer. There are three types of non-small cell cancer, which

account for over 80% of all cases of lung cancer. The three types of non-small cell lung

cancer are Squamous Cell Carcinoma, which begins to grow in the lining of the respiratory

tract, which is mad up of thin, flat cells; Adenocarcinoma, which originates in the lining of the

lung itself; and Large cell carcinoma, which forms tumors that look abnormally large when

observed 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. This

illustrates 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 the

obstruction 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 cancer

is 99 percent). If the cancer is diagnosed while it is localized (the tumor has not yet spread to

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distant 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 is spread, 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 of

lung cancer in the United States are due to the effects of smoking. Smoking accounts for about

one third of all cancers, not limited to lung cancer, though lung cancer is the cancer that is

linked most closely to smoking. Cigarettes have over 4000 chemicals, many of which have

been identified as cancer-causing. These chemicals can irritate cells in the lungs, and

eventually turn them into cancer cells, which then reproduce uncontrollably, and form a tumor.

Cigarettes isn’t the only tobacco product that causes cancer, in fact, any tobacco product is

hazardous to your health. This is because all of them contain the same carcinogenic

substances 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 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.

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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 a history

of lung cancer.

Symptoms

There are many symptoms associated with lung cancer. They range from mild and

harmless to painful and dangerous. The following symptoms are the most common ones that

people experience with lung cancer:

Shortness of breath

Coughing up blood

Incessant cough

Wheezing

Chest or abdominal pain

Weight loss (loss of appetite)

Hoarse voice

Clubbing of the finger nails (slightly less common than others)

Difficulty swallowing

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Sometimes the cancer can also grow into the airway, which can cause breathing

difficulty, and, as mentioned before, wheezing. The cancer can also have a very abundant

blood supply. Because the cancer has a weak surface, it can be ruptured, and this can cause

blood 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 can

perform a simple physical exam. This will not prove that the patient has cancer, but it will give

the 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, so

doctors can sometimes overlook them. The last major form of diagnosis is a biopsy, which can

come in multiple forms itself. These variants are a bronchoscopy, a needle biopsy, and

surgery.

Here is a cross-section x-ray of a normal lung, with no visible presence of a

tumor.

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Here is another cross-section of the same lung two years later. There is clearly an

obstruction in the right hand side of the lung. A doctor would probably recognize this as a

tumor in the early stages of development.

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:

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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%.

Surgeries

Segmental 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

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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)

Wedge 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

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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

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 chest

wall in which one or more ribs or rib segments are removed to reduce the size of the

thorax. This procedure is rarely done today, but we may care for patients who underwent

this procedure in the 1950s when it was a common treatment for chronic tuberculosis.

Chemotherapy

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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.

Description: Chemotherapy pills

http://www3.mdanderson.org/depts/hcc/fall99/images/pills.gif

Radiotherapy

Radiotherapy is the use of high-energy rays to kill cancer cells. It is sometimes

used alongside other treatments, most often chemotherapy. Radiotherapy can be used

to shrink a tumor, which will later be removed by surgery.

Radiotherapy works by bombarding cancerous cells with rays that disrupt its

duplication. It partially disables the cancerous cells from duplicating at their normal

rate, and makes DNA replication difficult. Because of this, radiotherapy has many

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unpleasant side effects, such as hair loss, and skin disorders. This is because these are

parts of the body that also reproduce very often, and the radiotherapy disrupts them as

it does the cancer cells.

Photodynamic Therapy

This type of treatment can be used when the patient’s tumor is inoperable. The

first stage of this treatment is the injection of a drug that is triggered by light, such as

lumin. Then, a bronchoscopy is performed. A bronchoscopy is the insertion of a

scope that is used to examine the airwaves. When the scope is near the tumor, it emits

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 the

body as close to the cancer as possible. These substances that produce radiation are called

radioisotopes. Internal radiation gives you a high dose of radiation in a shorter time than

with external radiation. Some internal radiation is permanent and some are temporary. In

some cases, both internal and external are used.

External Radiation Therapy

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An example of External Radiation Therapy would be External Beam Radiation

Therapy (EBT). It is a method that delivers a beam of high-energy x-rays to the location

of 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

Cryosurgery

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 or

spray. For internal tumors liquid nitrogen is circulated throughout the body with a hollow

instrument called a cryoprobe. The doctor uses a MRI or ultrasound to guide the

cryoprobe in its freezing process. After cryosurgery is performed on external tumors it

dissolves and forms a scab. After cryosurgery is performed on internal tumors it thaws

and is absorbed into the body.

Stages

Doctors will decide what treatment to give you based on the stage the tumor is at

in the lung. These stages take into account whether or not the cancer has spread to other

parts of the body, the physical size of the cancer, and whether or not the lymph nodes are

affected. The following table shows how the stage of the cancer is derived.

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Stage Tumor

Size/invasion of

lung

Spread to

Lymph Node

Spread to

body

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

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.

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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.

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BIBILIOGRAPHY

1. 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=1325

2. 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?

OpenDocument

4. Clinical Update, September 1999

http://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, 2005

http://www.radiologyinfo.org/en/info.cfm?pg=lungcancer&bhcp=1

6. Hong Kong Observatory, 21 Sep 2005

7. http://www.weather.gov.hk/radiation/tidbit/200509/man_made_4e.htm

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8. Yale Medical Group- Lung Cancer, October 28, 2005

http://ymghealthinfo.org/content.asp?pageid=P07258

9. National Cancer Institute- Lung Cancer, 09/10/2003

http://www.cancer.gov/cancertopics/factsheet/Therapy/cryosurgery

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