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Definition
Lung
cancer is a disease in which the cells of the lung tissues grow uncontrollably
and form tumors. It is the leading cause of death from cancer among both men and
women in the United States. The American Cancer Society (ACS) estimated that in
1998, at least 172,000 new cases of lung cancer were diagnosed, and that lung
cancer accounted for 28% of all cancer deaths, or approximately 160,000 people.
In 2002, the ACS reported that more than 150,000 Americans die from the disease
every year. Only 15 percent of people with lung cancer will live five years.
Types of Lung Cancer
There
are two kinds of lung cancers, primary and secondary. Primary
lung cancer (also called adenocarcinoma) starts in the lung
itself. Primary lung cancer is divided into small cell lung
cancer and non-small cell lung cancer, depending on how the
cells look under the microscope. Secondary lung cancer is
cancer that starts somewhere else in the body (for example,
the breast or colon) and spreads to the lungs.
Small cell cancer was
formerly called oat cell cancer, because the cells resemble oats in their shape.
About one-fourth of all lung cancers are small cell cancers. This type is a very
aggressive cancer and spreads to
other organs within a short time. It generally is found in people who are heavy
smokers. Non-small cell cancers account for the remaining 75% of lung cancers.
They can be further subdivided into three categories.
Incidence of
Lung Cancer
Lung cancer is rare
among young adults. It usually is found in people who are 50 years of age or
older, with an average age at diagnosis of 60. While the incidence of the
disease is decreasing among Caucasian men, it is steadily rising among
African-American men, and among both Caucasian and African-American women. This
change probably is due to the increase in the number of smokers in these groups.
In 1987, lung cancer replaced breast cancer as the number one cancer
killer among women.
Causes
SMOKING.
Tobacco smoking is the leading cause of lung cancer.
Ninety percent of lung cancers can be prevented by completely giving up tobacco.
Smoking marijuana cigarettes is considered yet another risk factor for
cancer of the lung. These cigarettes have a higher tar content than tobacco
cigarettes. In addition, they are inhaled very deeply; as a result, the smoke is
held in the lungs for a longer period of time.
EXPOSURE TO
ASBESTOS AND TOXIC CHEMICALS. Repeated exposure
to asbestos fibers, either at home or in the workplace, also is considered a
risk factor for lung cancer. Studies show that compared to the general
population, asbestos workers are seven times more likely to die from lung
cancer. Asbestos workers who smoke increase their risk of developing lung cancer
by 50-100 times. Besides asbestos, mining industry workers who are exposed to
coal products or radioactive substances, such as uranium, and workers exposed to
chemicals, such as arsenic, vinyl chloride, mustard gas, and other carcinogens,
also have a higher than average risk of contracting lung cancer.
ENVIRONMENTAL
CONTAMINATION. High levels of a radioactive gas
(radon) that cannot be seen or smelled pose a risk for lung cancer. This gas is
produced by the breakdown of uranium, and does not present any problem outdoors.
In the basements of some houses that are built over soil containing natural
uranium deposits, however, radon may accumulate and reach dangerous levels.
Having one's house inspected for the presence of radon gas when buying or
renting is a good idea. Other forms of environmental pollution (e.g., auto
exhaust fumes) also may slightly increase the risk of lung cancer.
In 2002, a study in the
Journal of the American Medical Association (JAMA) linked for the first time
long-term exposure to fine-particle air pollution to lung cancer deaths. The
risk of death from lung cancer increased substantially for people living in the
most heavily polluted metropolitan areas. Tiny particles from the air pollution
emitted from coal-fired power plants, factories and diesel vehicles are to
blame.
CHRONIC LUNG
INFLAMMATION AND SCARRING. Inflammation and
scar tissue sometimes are produced in the lung by diseases, such as silicosis
and berylliosis, which are caused by inhalation of certain minerals,
tuberculosis, and certain types of pneumonia. This scarring may
increase the risk of developing lung cancer.
FAMILY HISTORY.
Although the exact cause of lung cancer is not known,
people with a family history of lung cancer appear to have a slightly higher
risk of contracting the disease. In 2003, researchers were continuing work
aimed at learning why some smokers were more susceptible to lung cancer than
others. They discovered a type of DNA repair characteristic apparent in smokers
who were less likely to get lung cancer. Continued work along these lines could
lead to possible screening for DNA that makes some people at higher risk for
lung cancer.
Symptoms
Lung cancers tend to
spread very early, and only 15% are detected in their early stages. The chances
of early detection, however, can be improved by seeking medical care at once if
any of the following symptoms appear:
- a cough that does not go away
- chest pain
- shortness of breath
- persistent hoarseness
- swelling of the neck and face
- significant weight loss that is not
due to dieting or vigorous exercise
- fatigue and loss of appetite
- bloody or brown-colored spit or
phlegm (sputum)
- unexplained fever
- recurrent lung infections,
such as bronchitis or pneumonia
However, these symptoms
may be caused by diseases other than lung cancer. It is vital, however, to
consult a doctor to rule out the possibility that they are the first symptoms of
lung cancer.
If the lung cancer has
spread to other organs, the patient may have other symptoms, such as headaches,
bone fractures, pain, bleeding, or blood clots. Early detection and
treatment can increase the chances of a cure for some patients. For others, it
can at least prolong life.
Physical
examination and initial tests
If the patient's doctor
suspects lung cancer, he or she will take a detailed medical history to check
all the symptoms and assess the risk factors. The assessment of the patient's
medical history will be followed by a complete physical examination. The doctor
will examine the patient's throat to rule out other possible causes of
hoarseness or coughing, and listen to the patient's breathing and the sounds
made when the patient's chest and upper back are tapped (percussed). The
physical examination, however, is not conclusive.
If the doctor has reason
to suspect lung cancer—particularly if the patient has a history of heavy
smoking or occupational exposure to substances that are known to irritate the
lungs—he or she may order a chest x ray to see if there are any masses in the
lungs. Special imaging techniques, such as CT scans or MRIs, may provide more
precise information about the possibility, size, shape, and location of any
tumors.
A technology called
spiral CT, which rotates allowing for images of the chest from all angles, can
detect lung cancer when tumors are smaller than a dime. A report in 2002 said
spiral CT technology could help doctors screen the population for lung cancer,
but the idea of screening remains controversial. Until clinicians and insurers
receive more proof the scans produce fewer false positive (a seemingly positive
result or nodule that turns out not to be a cancerous mass), widespread
screening won't occur. And in 2002, the cost of a spiral CT chest study to
screen for lung cancer averaged about $400. However, researchers were
recommending further trials to determine the effectiveness of the screening tool
for future use.
In 2003, a new radiology
technique emerged for staging lung cancer. By combining positron emission
tomography (PET) with CT, or PET-CT, physicians could more accurately see the
details of the tumorís progression (or regression after treatment) and to
diagnose a lung tumor better.
Sputum analysis involves
microscopic examination of the cells that are either coughed up from the lungs,
or are collected through a special instrument called a bronchoscope. Sputum
analyses can diagnose at least 30% of lung cancers, some of which do not show up
even on chest x rays. In addition, the test can help detect cancer in its very
early stages, before it spreads to other regions. The sputum test does not,
however, provide any information about the location of the tumor and must be
followed by other tests, such as bronchoscopy, where machines can detect
cancerous cells without the need to open the chest.
Lung biopsy is the most
definitive diagnostic tool for cancer. It can be performed in several different
ways. The doctor can perform a bronchoscopy, which involves the insertion of a
slender, lighted tube, called a bronchoscope, down the patient's throat and into
the lungs. In addition to viewing the passageways of the lungs, the doctor can
use the bronchoscope to obtain samples of the lung tissue. In another procedure
known as a needle biopsy, the location of the tumor first is identified using a
CT scan or
MRI. The doctor then inserts a needle through the chest wall and collects a
sample of tissue from the tumor. In the third procedure, known as surgical
biopsy, the chest wall is opened up and a part of the tumor, or all of it, is
removed. A doctor who specializes in the study of diseased tissue (a
pathologist) examines the tumor samples to identify the cancer's type and stage.
Treatment
Alternative therapies
should complement conventional treatment, not replace it. Before participating
in any alternative treatment programs, patients should consult their doctors
concerning the appropriateness and the role of such programs in overall cancer
treatment plans. Appropriate alternative treatments can help prolong a patient's
life or at least improve quality of life, prevent recurrence of tumors, or
prolong the remission period and reduce adverse reactions to chemotherapy and
radiation.
The use of beta-carotene
and vitamin A supplements in lung cancer patients is controversial.
Vitamin A and beta-carotene were advocated as antioxidants with
lung-protective effects that may decrease the risk of lung cancer. However,
recent studies suggest that betacarotene supplements may have no demonstrated
effect in smokers and no effects on nonsmokers. Therefore, use of beta-carotene
supplement in lung cancer patients or as preventive measure in smokers is not
recommended at the present time. However, researchers believe that patients
benefit from nature's source of beta-carotene and vitamin A. Beta-carotene in
food carries all the benefits, yet does not have the harmful effects
controversial high-dose supplements may carry.
The effectiveness of
many of the anticancer drugs used to treat lung cancer can be reduced when
patients take megadoses of antioxidants. These antioxidants in patients not
undergoing chemotherapy can be helpful in protecting the body against cancer.
However, taken during chemotherapy, these antioxidants protect the cancer cells
from being killed by chemotherapy drugs. Because high-dose supplementation of
antioxidants can interfere with conventional chemotherapy treatment, patients
should check with their physicians concerning dosage and recommended daily
allowance (RDA) during chemotherapy or radiation therapy. [ More details]
Dietary
guidelines
The following dietary
changes may help improve a patient's quality of life, as well as boost the
immune function to better fight the disease. They also may help prevent lung
cancer.
-
Avoiding fatty and
spicy foods. A high-fat diet may be associated with increased risk of lung
cancer. Also, lung cancer patients may have a hard time digesting heavy foods.
-
Eating new and
exciting foods. Tasty foods stimulate appetite so that patients can eat more
and have the energy to fight cancer.
-
Increasing consumption
of fresh fruits and vegetables. They are nature's best sources of
antioxidants, as well as vitamins and minerals. Especially helpful are the
yellow and orange fruits (orange, cantaloupes) and dark green vegetables. They
contain high amounts of vitamin A and carotene.
-
Eating more broccoli
sprouts. These young sprouts are a good source of sulforaphane, a lung cancer
fighting substance.
- Eating multiple (5-6) meals per day.
Small meals are easier to digest.
- Establishing a regular eating time
and not eating around bedtime.
- Avoiding foods containing
preservatives or artificial coloring.
- Monitoring weight and intake of
adequate calories and protein.
In 2002, a report in
Family Practice News said that daily consumption of a soup used in
Traditional Chinese Medicine helped slow the progression of non-small cell
lung cancer for patients with advanced stages of the disease. The soup consisted
of herbs and vegetables containing natural ingredients that boost immunity and
help fight tumors. Patients should check with their doctors and with a licensed
Traditional Chine Medicine specialist for more information. The soup does not
prevent or reverse the disease, but helped prolong survival for a percentage of
patients in a clinical study.
A naturopath may
recommend some of the following nutritional supplements to boost the patient's
immune function and help fight tumor progression:
-
Vitamins and minerals.
Vitamins that are considered particularly beneficial to cancer patients
include B-complex vitamins, especially vitamins B6, C, D, E, and K.
Most important minerals are calcium, chromium, copper, iodine,
molybdenum, germanium, selenium, tellurium, and zinc. Many of
these vitamins and minerals are strong antioxidants or cofactors for
antioxidant enzymes. However, patients should not take mega doses of these
supplements without first consulting their doctors. Significant adverse or
toxic effects may occur at high dosages, which is especially true for the
minerals.
-
Other nutritional
supplements may help fight cancer and support the body. They include
essential fatty acids (fish or flaxseed oil), flavonoids,
pancreatic enzymes (to help digest foods), hormones such as DHEA, melatonin,
or phytoestrogens.
Conventional treatment
for leukemia is associated with significant side effects. These adverse
effects (such as nausea, vomiting, and fatigue) can be reduced with
Chinese herbal preparations. Patients should consult an experienced herbalist
who will prescribe remedies to treat specific symptoms that are caused by
conventional cancer treatments.
Juice therapy may be helpful for
patients with cancer. Patients should mix one part of pure juice with one part
of water before drinking.
There is
conflicting evidence regarding the effectiveness of homeopathy in cancer
treatment. Because cancer chemotherapy may suppress the body's response to
homeopathic treatment, homeopathy may not be effective during chemotherapy.
Therefore, patients should wait until after chemotherapy to try this relatively
safe alternative treatment.
Acupuncture is the use
of needles on the body to stimulate or direct the meridians (channels) of energy
flow in the body. Acupuncture has not been shown to have any anticancer effects.
However, it is an effective treatment for nausea, and other common side effects
of chemotherapy and radiation.
Other Treatments
Other alternative treatments include stress reduction, meditation, yoga and the use of
guided imagery A new report in 2003 showed early results for bee venomís
possible antitumor effects on lung cancer. However, further, research was
needed.
Treatment for lung
cancer depends on the type of cancer, its location, and its stage. Treating the
cancer early is key. In 2002, researchers announced the discovery of a
chromosomal region that shows the earliest genetic change in the development of
lung cancer. Eventually, this discovery could lead to earlier detection,
diagnosis, prevention, and treatment of lung cancer. The most commonly used
modes of treatment are surgery, radiation therapy, and chemotherapy.
Surgery is not usually
an option for small cell lung cancers, because they have likely spread beyond
the lung by the time they are diagnosed. Because non-small cell lung cancers are
less aggressive, however, surgery can be used to treat them. The surgeon will
decide on the type of surgery, depending on how much of the lung is affected.
Surgery may be the primary method of treatment, or radiation therapy and/or
chemotherapy may be used to shrink the tumor before surgery is attempted.
There are three
different types of surgical operations:
The pain that follows
surgery can be relieved by medications. A more serious side effect of surgery is
the patient's increased vulnerability to bacterial and viral infections.
Antibiotics, antiviral medications, and vaccines are often needed.
Radiation therapy
involves the use of high-energy rays to kill cancer cells. It is used either by
itself or in combination with surgery or chemotherapy. There are two types of
radiation therapy treatments: external beam radiation therapy and internal (or
interstitial) radiotherapy. In external radiation therapy, the radiation is
delivered from a machine positioned outside the body. Internal radiation therapy
uses a small pellet of radioactive materials placed inside the body in the area
of the cancer.
Radiation therapy may
produce such side effects as tiredness, skin rashes, upset stomach, and
diarrhea. Dry or sore throats, difficulty in swallowing, and loss of hair in the
treated area are all minor side effects of radiation. These may disappear either
during the course of the treatment or after the treatment is over. The side
effects should be discussed with the doctor.
Chemotherapy uses anticancer medications that are either given intravenously or
taken by mouth (orally). These drugs enter the bloodstream and travel to all
parts of the body, killing cancer cells that have spread to different organs.
Chemotherapy is used as the primary treatment for cancers that have spread
beyond the lung and cannot be removed by surgery. It also can be used in
addition to surgery or radiation therapy.
Chemotherapy is tailored
to each patient's needs. Most patients are given a combination of several
different drugs. Besides killing the cancer cells, these drugs also harm normal
cells. Hence, the dose has to be carefully adjusted to minimize damage to normal
cells. Chemotherapy often has severe side effects, including nausea, vomiting,
hair loss, anemia, weakening of the immune system, and sometimes
infertility. Most of these side effects end when the treatment is over.
Other medications can be given to lessen the unpleasant side effects of
chemotherapy.
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.
Due to improvements in
surgical technique and the development of new approaches to treatment, the
one-year survival rate for lung cancer has improved considerably. As of 1998,
approximately 40% of patients survive for at least a year after diagnosis, as
opposed to 30% that survived 20 years ago. In 2003, 14% of people diagnosed with
lung cancer were reported to be long-term survivors.
The best way to prevent
lung cancer is to not smoke or to quit smoking if one has already started.
Secondhand smoke from other people's tobacco also should be avoided when
possible. In 2002, a report on the impact of cigarette smoking said that in
California, decreases in smoking among residents had resulted in reduced lung
cancer death rates.
Appropriate precautions
should be taken when working with cancer-causing substances (carcinogens).
Monitoring the diet and eating well-balanced meals that consist of whole foods,
vegetables, and fruits; eliminating toxins, exercising routinely, and weight
reduction; testing houses for the presence of radon gas, and removing asbestos
from buildings also are useful preventive strategies.
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Organizations
American Cancer Society. 1599 Clifton Road, N.E.,
Atlanta, GA 30329. (800)227-2345.
American Lung Association. 1740 Broadway, New York, NY
10019-4374. (800) 586-4872.
Cancer Research Institute. 681 Fifth Avenue, New York,
NY 10022. (800) 992-2623.
National Cancer Institute (National Institutes of
Health). 9000 Rockville Pike, Bethesda, MD 20892. (800) 422-6237.
Other
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Prevention Trial." Medical Sciences Bulletin.
http://pharminfo.com.
Rosenberg, Z'ev. "Treating the Undesirable Effect of
Radiation and Chemotherapy with Chinese Medicine." Oriental Chinese Journal.
http://www.healthypeople.com.
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