Reviewed by Charles Patrick Davis, MD, PhD
Lung Cancer Symptoms, Stages, Treatment
This tool does not provide medical advice
Lung Cancer: The Leading Cause of Cancer Death
Lung cancer has emerged
as the leading killer of men and women stricken with invasive cancer, affecting
husbands and wives, friends and neighbors, and causing suffering for many
families. In the United States, lung cancer overtook breast cancer as the leading
cause of cancer deaths in women in 1987. Lung cancer deaths account for a
quarter of all American cancer deaths, killing more people every year than
prostate, breast, and colon cancer combined. Over 157,000 Americans are
estimated to have died from lung cancer in 2015.
This disease is
difficult to detect in its early stages, and treatments for lung cancer in its
later stages provide a poor prognosis: Those with stage IV non-small cell lung
cancer—the most common type—have an estimated 1 percent survival rate five
years after diagnosis. The other type of lung cancer—small cell lung cancer—is
even more aggressive. According to the American Cancer Society, the overall
survival rate for lung cancer as of Jan. 1, 2014 stands at just 3%.
What Causes Lung Cancer?
The
exact cause of lung cancer is still being investigated. Certain risk factors
have been shown to play a part in causing cells to become cancerous. Risk
factors for lung cancer include smoking, exposure to air pollution, and
genetics.
Does Smoking Cause Lung Cancer?
The
major cause of lung cancer in men and women is mainly due to cigarette smoking.
In 1876, a machine was invented to make rolled-up cigarettes and thus provided
cheap tobacco products to almost everyone. At that time, lung cancer was relatively
rare. Smoking dramatically increased and so did lung cancers following this
innovation. Currently about 90% of all lung cancers are related to smoking.
Radon gas, pollution, toxins, and other factors contribute to the remaining
10%.
Cigarettes
and cigarette smoke contains over 70 cancer-causing chemicals (carcinogens).
Some of the carcinogens found in cigarette smoke include:
·
Lead (a highly poisonous metal)
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Arsenic (an insecticide)
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Cadmium (a battery component)
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Isoprene (used to make synthetic rubber)
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Benzene (a gasoline additive)
Cigar
smoke is particularly heavy on tobacco-specific nitrosamines (TSNAs), which are
considered particularly cancerous.
Lung Cancer and Cilia
Cigarette
smoke damages and can kill hair-like projections on airway cells termed cilia.
The cilia normally sweep out toxins, carcinogens, viruses, and bacteria. When
the cilia are damaged or destroyed by smoke, all of these items may accumulate
in the lungs and may cause problems such as infections or lung cancer.
Lung Cancer Symptoms
Unfortunately,
lung cancers often have either no early symptoms or nonspecific early symptoms
that people often dismiss. About 25% of people with lung cancer and no symptoms
are diagnosed after having a chest X-ray or CT during a routine test or as a
procedure for other problems. Lung cancer symptoms that may be detected are
included below.
List of Lung Cancer Symptoms
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Cough (chronic, recurrent)
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Fatigue
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Weight loss
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Shortness of breath or wheezing
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Coughing up phlegm that contains blood
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Chest pain
Three Common Lung Cancer Screening Methods
Screening
for lung cancer is usually accomplished using three methods.
Physical Exam
A
physical exam will look for signs of wheezing, shortness of breath, cough, pain
and other possible signs of lung cancer. Depending on the advancement of the
cancer, other early signs of lung cancer symptoms may include a lack of
sweating, dilated neck veins, face swelling, excessively constricted pupils,
and other signs. The physical exam will also include the patient’s history of
smoking and a chest X-ray.
Sputum Cytology Exam
A
sputum cytology exam involves a microscopic examination of a patient’s mucus
(sputum).
Spiral CT Exam
This
method of CT scanning builds a detailed image of the body’s internal workings.
Inside a spiral CT machine, detailed images are taken of the relevant parts of
the patient’s body. Those images are then linked to an X-ray machine to create
3D images of the patient’s internal organs. These images may reveal potentially
cancerous tumors.
A
study by researchers suggested that people aged 55 to 74 years old who had
smoked at least one pack of cigarettes a day for 30 or more years may benefit
from a spiral CT study of the lungs. At best, the screening methods find about
30% of lung cancers leaving the bulk (about 70%) cancers of lung undetected. In
addition, some test results are not clearly diagnostic which can lead to
patient concerns and possibly unnecessary biopsies or surgeries.
Lung Cancer Diagnosis
If the screening tests
suggest a person has lung cancer, definitive diagnostic tests may be done by a
pathologist. The pathologist will examine the patient’s lung cells in sputum,
phlegm, or from a biopsy sample to type and stage the lung cancer.
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Lung Cancer: Biopsy
As
stated previously, a tissue sample taken from the patient’s suspected cancer is
usually the best method to establish a definitive lung cancer diagnosis. In
general, lung biopsies are obtained by either needle biopsy, a lung
bronchoscopy technique, or by surgical removal of tissue. Many other tests may
be done to get more information about the cancer’s spread.
See
the following slides for types of lung cancer and lung cancer stages, including
stage IV lung cancer.
Types of Lung Cancer
There
are only two major types of lung cancers: small cell lung cancer and non-small
cell lung cancers. Less than 5% of lung cancer tumors will take the form of a
carcinoid tumor, while other cancerous tumors are even more rare, including
adenoid cystic carcinomas, lymphomas, and sarcomas. Although cancer from
another part of the body may spread to the lungs, these are not categorized as
lung cancer.
Non-Small Cell Lung Cancer
Non-small
cell lung cancers are the most common type of lung cancer. These cancers
account for about 90% of all lung cancers and are less aggressive than small
cell lung cancers, meaning they spread to other tissues and organs more slowly.
Small Cell Lung Cancer
Small
cell lung cancer, also called oat cell lung cancer, accounts for about 10% of
all lung cancers. This form of cancer tends to spread quickly.
Lung Cancer Stages: Stage 0 Through Stage 4
After
the type of lung cancer is determined, the type is then assigned a lung cancer
stage. The stage indicates how much the cancer has spread in the body (for
example, to the lymph nodes or to distant organs like the brain). Stages for
non-small cell lung cancers are different from small cell lung cancers. The
stages listed below are taken from the National Cancer Institute’s lung cancer
staging information:
Small Cell Lung Cancer Stages
Limited
stage: In this form, small cell lung cancer is limited to one side of the
chest, typically in the lungs and lymph nodes. About one in three people with
small cell lung cancer have limited stage cancer upon the first diagnosis.
Extensive
stage: This refers to small cell lung cancer that has spread throughout one
lung, spread into both lungs, to lymph nodes on the other side of the chest or
to other body parts. About two in three people with small cell lung cancer have
extensive stage cancer upon first diagnosis.
Non-Small Cell Lung Cancer Stages
Occult
(hidden) stage: In this stage, cancer cells appear in a sputum cytology exam or
other test, though no tumor location can be found.
Stage
0 (carcinoma in situ): In this lung cancer stage, cancer cells are only found
in the top layer of cells lining air passages and has not crept deeper into the
lungs or spread beyond the air passages.
Stage
I: A small lung cancer tumor (less than 3 centimeters across) is discovered,
but has not spread to surrounding lung membranes, lymph nodes, or the main
bronchial branches of the lungs.
Stage
II: There are several ways that stage II lung cancer may be diagnosed. One is
that the lung cancer has spread to lymph nodes near the lungs.
·
Stage IIA: If the tumor is between 3 centimeters and 5
centimeters, the lung cancer is defined as stage IIA. Other factors can lead to
this classification as well.
·
Stage IIB: If the lung cancer tumor is between 5 centimeters and 7
centimeters, it is categorized as Stage IIB. Other factors can lead to this
classification as well.
Stage
III: As in stage II lung cancer, stage III has several definitions. One is that
the lung cancer is found in both the lung and lymph nodes in the middle of the
chest. Stage III lung cancer is divided into two subsets.
·
Stage IIIA: This defines a lung cancer that has spread on the same
side of the chest from where it started.
·
Stage IIIB: This defines a lung cancer in which the cancer has
spread to either the opposite side of the chest or above the collar bone.
Stage
IV: This is the most advanced stage of lung cancer. The cancer can be any size,
but two of these three things have happened:
·
The cancer has spread to the opposite lung from where it began.
·
Cancer cells have been discovered in the fluid surrounding the
lung.
·
Cancer cells have been discovered in the fluid surrounding the
heart.
Lung Cancer Survival
Rates
The American Cancer
Society statistics are currently based on people diagnosed between 1998 and
2000 so the data may not reflect the effects of newer treatments. The data
indicates that survival rates of patients living 5 years after being diagnosed
with non-small cell lung cancers was dependent on the stage of the disease.
Stage I was about 49%
(with surgical removal, about 75%) while stage IV survival was about 1%. Small
cell lung cancers are more aggressive and the data, like that for non-small
cell lung cancers, is not reflective of current survival rates.
However, even some data
collected as late as 2008 indicates slow progress in increasing 5-year survival
rates. The overall rate of both limited-stage and extensive-stage small cell
lung cancer is about 6%. The overall rate of all stages (I to IV combined)
non-small cell lung cancer is about 15%.
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Early-Stage Lung Cancer Treatment: Surgery
Early
stage (stage 0 or even some stage I) cancer treatment of non-small cell lung
cancer may benefit from surgery. Part or all of a lung segment that contains
the cancer may be removed; in some individuals, this may result in a cure.
However, many patients still undergo chemotherapy, radiation therapy or both to
kill any cancer cells not removed by surgery. Because small cell lung cancers
are almost never diagnosed early, surgery (and other treatments) may prolong
life but rarely, if ever, result in a cure.
Advanced Lung Cancer Treatment
Most
small cell and non-small-cell lung cancers are treated with chemotherapy; they
may also be treated with radiation therapy and surgery. In many patients with
advanced disease, these methods may be used together, depending on the
patient's condition and recommendations by their cancer doctors.
Targeted Lung Cancer Therapies
New
therapeutic treatments are being tried; for example, some therapies termed
targeted therapies are designed to prevent or stop lung cancer cells from
growing by targeting the new blood vessels that are needed to allow the cancer
cells to survive and grow; other treatments target growth and multiplication of
lung cancer cells by interfering with chemical signals required by growing or
multiplying cancer cells
Clinical Trials for Lung Cancer
In
addition to targeted therapies, there are a number of clinical trials that a
person may qualify for. Some may be available in your hometown. These clinical
trials have patients try the newest potentially helpful therapeutic methods and
drugs to combat lung cancers. The National Cancer Institute’s web site listed
below offers a list of current clinical trials; you and your doctor may find a
clinical trial that may help you with this disease.
Life After Lung Cancer Diagnosis
After
a diagnosis of lung cancer, it is not unusual to feel depressed and upset.
However, research is ongoing and it is possible to survive and extend your life
with treatment. Even with the diagnosis, there is evidence that people who
develop a healthy lifestyle and stop smoking do better than those who do not
change.
Lung Cancer and Secondhand Smoke
Tobacco
smokers put others at risk of developing lung cancer. A nonsmoker (wife, child,
significant other) who lives with a smoker has a 20% to 30% increase in risk of
de
Lung Cancer and Work Exposures
Although
smoking results in the highest risk of causing lung cancers, other
environmental exposures to certain compounds and chemicals increase the risk of
lung cancer. Such agents as asbestos, uranium, arsenic, benzene, and many others
increase the risk for developing lung cancers. Exposure to asbestos may cause
lung cancer (mesothelioma) many years after the initial exposure so people may
be at risk for lung disease for decades (10 to 40 years
Lung Cancer and Radon Gas
Another
chemical, radon gas, is considered to be the second leading cause of lung
cancer. It occurs naturally but can seep into homes and collect in basements
and crawl spaces. It is colorless and odorless but can be detected with
relatively simple and inexpensive test kits. Smokers exposed to this gas have a
higher risk of developing lung cancer than nonsmokers.
Lung Cancer and Air Pollution
There
are a number of investigators that suggest air pollution contributes to the
development of lung cancers. Several studies present data that airborne
pollutants like diesel exhaust may cause some people to develop lung cancers.
Researchers estimate that about 5% of lung cancers are due to air pollutants.
Increased Risk Factors for Lung Cancer
Although
much is understood about lung cancers, there are still many things and
situations that are unclear. For example, it is unclear why some families have
a history of individuals with lung cancer and no clear risk factors. The same
is true for some patients who develop lung cancers with no clear risk factors.
Another occurrence such as drinking water that has high arsenic concentrations
may increase lung cancer risk but how the process happens is not clear. In
addition, the reason why adenocarcinoma in the lungs is more common in nonsmokers
than smokers is also not known.
Lung Cancer Prevention
For the majority of lung cancers,
prevention is possible if a person never smokes and avoids second-hand smoke.
For smokers who quit -- within 10 years -- the risk of getting lung cancer
drops to about the same risk as if they had never smoked. Avoiding other risk
factors (for example, certain chemicals or compounds like benzene or asbestos
or air pollution) may also prevent some people from developing lung cancers.
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