Introduction
Lung cancer is the most prevalent and the most
lethal form of cancer. There will be nearly two hundred thousand new
case of lung cancer diagnosed this year. And of those new cases, only
one in ten will reach the five-year anniversary date of their
diagnosis.
The disease affects both men and women,
smokers and nonsmokers, although smokers are 90 percent more likely to
develop lung cancer than nonsmokers.
Another major cause of lung cancer is
second-hand smoke. A nonsmoker living with a smoker has twice the
incidence of lung cancer than a nonsmokers living with another
nonsmoker. Some of the other causes include exposure to air pollution,
asbestos, radon gas, genetics and viruses.
The treatment and the prognosis depend upon
the type and whether or not the disease has spread to other organs.
Currently, only 16 percent of all lung cancer are diagnosed at stage
one or stage two. Most commonly, the diagnosis is made when the
disease is at stage three or stage four -- and that makes it very
unlikely that the patient will reach a five-year survival anniversary.
The advanced stages are the most common
presentation, because that is when the patient begins to experience
symptoms. The symptoms of lung cancer include shortness of breath,
dyspnea, cough, hemoptysis, weight loss due to loss of appetite, along
with fatigue and pain in the chest or abdomen.
Types
The two main types of lung cancer are
non-small cell (80 percent) and small cell (20 percent). Non-small
cell lung cancer (NSCLC) can be managed in approximately the same way,
and their outcomes are similar.
The NSCLCs include squamous cell carcinoma (20
percent to 25 percent), adenocarcinoma (50 percent to 60 percent),
bronchoalveolar carcinoma, (this type is a subtype of adenocarcinoma,
and the most common type of lung cancer in female nonsmokers).
Large cell carcinoma is a fast-growing form
that grows near the surface of the lung.
Small-cell lung cancer (SCLC), also called oat
cell carcinoma, is the less common form of lung cancer. It tends to
start in the large airways and grows rapidly. This type of lung cancer
is most common among smokers and it has often metastasized before the
patient is diagnosed with lung cancer.
Less Common Types
There are four less common types of lung
cancer -- carcinoid, carcinoma, and cylindroma and mucoepidermoid
carcinoma. Several cancers metastasize to the lung -- the adrenal
gland, liver, brain and bone are the most common. These same sites are
the most common sites for a primary lung cancer to spread to as well.
Lung Cancer Staging
The International Staging System for Lung
Cancer TNM classification is as follows:
Stage 0
The cancer is limited to the air passageways
and has not invaded the lung tissue. The cancer can usually be
eliminated.
Stage I
The cancer has spread to layers of the lung
tissue, but has not spread to the lymph nodes or beyond. There is a 60
percent to 80 percent chance of surviving this disease for five years.
Stage II
The cancer has invaded the neighboring lymph
nodes or has spread to the chest wall. There is a 40 percent to 50
percent chance of surviving the disease for five years.
Stage IIIa
The cancer has spread from the lung to the
lymph nodes beyond the lung area. There is a 15 percent to 40 percent
chance of surviving the disease for five years.
Stage IIIb
The cancer has spread to areas such as the
heart, blood vessels, trachea, esophagus, and within the chest wall.
There is a 10 percent to 15 percent chance of surviving the disease
for five years.
Stage IV
The cancer has spread to other parts of the
body such as the brain, bone or liver. There is less than a 2 percent
chance of surviving the disease for five years.
Staging also includes the classification of T=
tumor, N= nodes, M= metastasis
T0= no tumor
T is= carcinoma in situ
T1 = tumor 3 cm or less, not invading the
pleura and no invasion of the proximal lobar bronchus.
T2 = greater than 3cm, invasion of the pleura,
with proximal extension at least 2 cm away from the carina,
involvement of the main stem bronchus, association with atelectasis or
obstruction.
T3 = invasion of the chest wall, diaphragm,
mediastinal pleura, parietal pericardium. Includes involvement of the
main stem bronchus, association with atelectasis or pneumonitis of the
entire lung.
T4 = invasion of the mediastinum, heart, great
vessels, trachea, esophagus, vertebral body or carina. Association
with malignant pleural pericardial effusion or the presence of any
satellite tumor nodules with the lode of the lung containing the
primary tumor.
N0 = no regional lymph node involvement
N1 = involvement of ipsilateral per bronchial,
intrapulmonary and/or hilar either by metastasis or direct extension.
N2 = involvement of ipsilateral mediastinal
and/or subcarinal lymph nodes.
N3 = Metastasis to contralateral mediastinal
of contralateral hilar nodes or involvement of scalene or
supraclavicular nodes.
M0 = No distant metastasis
M1 = Distant metastasis present.
Detection Methods
As the stages of the disease increase, the
chance that the patient will survive for at least five years goes
down. But unlike other cancers such as colon, prostate and breast
cancers, there is currently no screening tool for lung cancer. That
makes early detection of this disease even more crucial.
The physical exam is where it all begins.
Check for weight loss, fatigue, shortness of breath, smoking history,
family history, complaints of cough, and complaints of chest pain.
Listen to the lungs for any abnormal breath sounds, evaluate the chest
for breathing pattern, and feel for enlarged lymph nodes. Sputum
cytology, phlegm coughed up from the lungs and examined under the
microscope to check for abnormal or cancerous cells, is an easy way to
gather information about the health of the patient's lungs.
A baseline chest X-ray is helpful on patients
with a family history of lung cancer or a smoking history, and, of
course, for any patient who has any symptoms of lung cancer.
A chest X-ray is a flat one-dimensional
picture of the lungs, while a CT scan is a two-dimensional scan from a
series of images. The newest version of the CT scan is the spiral CT
scan, which takes 15 to 25 seconds during a large breath, creating a
there dimensional image.
A positron emission tomography (PET) scan is
helpful in locating cancerous tumors; it traces the way that cells
react to radioactive sugar. Magnetic resonance imaging (MRI) is
similar to a CT scan, but it uses a magnetic field in place of X-rays
to create an image.
Navigational Bronchoscopy
If a lung mass or a lymph node is identified
that may be suspicious for lung cancer, the patient may be scheduled
for a bronchoscopy. During the bronchoscopy, the doctor will attempt
to obtain tissue using a variety of methods. He can take biopsies, he
can take Wang needle aspirations, or use cell washing or
bronchoalveolar lavage (BAL).
If the patient has a peripheral lesion and
fluoroscopy is needed, the patient may require a fine needle
aspiration (FNA) in an attempt to retrieve tissue. However this
procedure has the risk of producing a pneumothorax.
Recently, there has been a new method
developed that has dramatically reduced the number of pneumothorax. It
is called navigational bronchoscopy. Navigational bronchoscopy uses
GPS-like technology (global positioning system). The navigational
system reads a CT scan and creates a three-dimensional (3D) virtual
bronchoscopy image. Before the procedure, the lesion of interest is
identified on the CT scan and programmed into the computer along with
the normal anatomic landmarks. Then the patient lies on an
electrometric field and three leads are attached to help the computer
adjust for chest motion. Using the CT image as a roadmap, it guides to
the peripheral lesion.
This method has less risk than the FNA and
helps to safely get the diagnosis so that a treatment plan can be put
into place for the patient.
Fluorescence Bronchoscopy
Fluorescence bronchoscopy is a new method of
detecting lung cancer before it is in the invasive stage. The
fluorescence scope shines a blue light on the tissue, and the healthy
tissue gives off a green autofluorescence color. The color changes
when the tissue progresses from healthy to cancerous. The color change
is displayed on the monitor and the doctor can then take biopsies of
the tissue that he may not have noticed under normal white light
bronchoscopy. Finding a cancer in an earlier stage can make a big
difference in the patient's future. For all the many ways that we have
to diagnose lung cancer, we are still not able to reduce the number of
deaths per year from this horrible disease. Screenings like those for
breast, prostate, and colon cancers may be in the future for smokers
and those with a family history of the disease. But currently, the
best way to prevent lung cancer is to never start smoking and to stop
smoking if you do. There are many ways to help you quit -- ask your
doctor, and be sure to encourage your patients to stop smoking.
Cynthia R. King, RN, BSN, CCRN, has worked
at the Nashville VA Medical Center for 10 years. She has worked eight
years in the MICU and the last two in the endoscopy lab. She lives in
Franklin, Tenn., with her husband and two children.
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