Encyclopedia of Health and Medicine

210 The Pulmonary System
The least aggressive of the three types of NSCLC is
squamous cell carcinoma, which most commonly
occurs as a consequence of cigarette smoking.
Some people have more than one type of NSCLC
at the time of diagnosis.
Small Cell Lung Cancer (SCLC)
Cigarette smoking causes nearly all SCLC. Small
cell lung cancer has a characteristic appearance
microscopically, sometimes described as “oat cell.”
This type of lung cancer grows rapidly and often
has metastasized by the time of diagnosis. The
outlook (prognosis) for extensive SCLC is particularly
poor, with a one-year survival rate of about
20 percent. About 70 percent of people have
extensive SCLC at the time of diagnosis.
Malignant Mesothelioma
Malignant mesothelioma is a rare form of cancer
that occurs mostly in people who have had exposure
to asbestos, particularly those who have
ASBESTOSIS (a condition of damage to the lungs
resulting from asbestos exposure). Malignant
mesothelioma commonly arises from the PLEURA,
the membrane that covers the lung. Other
mesothelial membranes in the body include the
PERICARDIUM, which surrounds the HEART, and the
peritoneum, which lines the abdominal cavity.
Malignant mesothelioma may also arise from
these membranes, though that is less common.
Malignant mesothelioma often does not show
symptoms until it is well advanced, invading the
lungs and adjacent organs or spreading through
the LYMPH vessels to sites throughout the body.
Doctors diagnose about 2,000 people with malignant
mesothelioma each year in the United States
and stage it similarly to NSCLC.
NONMALIGNANT MESOTHELIOMA
A noncancerous form of mesothelioma, benign
fibrous mesothelioma, may grow from the PLEURA
to reach considerable size, compressing inward
on the lung or causing PLEURAL EFFUSION. Treatment
is surgery to remove the tumor, which
cures the condition. Benign fibrous mesothelioma
does not spread and does not return after
removal, though new tumors may develop in
other mesothelial membranes.
Symptoms and Diagnostic Path
Early symptoms of lung cancer are often general
and do not point specifically to a pulmonary condition.
These early symptoms include
• fatigue
• HEADACHE
• loss of APPETITE and unintended weight loss
• dizziness, confusion, and memory disturbances
• JOINT aches and BONE PAIN
• FEVER without evidence of INFECTION
As the cancer becomes more established and
takes over more of the lung, symptoms are more
specific. These more specific symptoms include
• persistent COUGH
• HEMOPTYSIS (coughing up bloody sputum)
• chest or back pain
• wheezing (whistling sound with exhalation)
• DYSPNEA (shortness of breath)
The diagnostic path begins with a comprehensive
medical examination including chest X-RAY
and diagnostic blood tests. The chest X-ray may
show an abnormality that, with an appropriate
history, would suggest a diagnosis of cancer. Further
diagnostic procedures may include COMPUTED
TOMOGRAPHY (CT) SCAN, MAGNETIC RESONANCE IMAGING
(MRI), POSITRON EMISSION TOMOGRAPHY (PET) SCAN,
and lung biopsy, BRONCHOALVEOLAR LAVAGE, or
exploratory THORACOTOMY.
A crucial element of diagnosis and treatment
planning is staging, which identifies the extent to
which the cancer has spread. Doctors may perform
additional diagnostic procedures to determine
the lung cancer’s stage. Non–small cell lung
cancer and malignant mesothelioma follow a standard
cancer staging scale. Because SCLC is so
extraordinarily aggressive it follows a unique staging
scale that primarily defines the disease as
either limited or extensive.
Treatment Options and Outlook
Treatment options and outlook vary according to
the type and stage of lung cancer as well as the
person’s overall health status. Recommendations