Cancer Disease
References and
selected reading
Cancer is the second killer disease in the western
world (after heart disease). In the USA, more than half
million people were estimated to die from cancer in 2008
(1). Breast cancer is the most prevalent cancer among women;
and prostate cancer is the most prevalent among men (1).
Lung cancer, is the second most prevalent cancer both in men
and women, but is the first killer cancer disease in both
sexes (1).
The body organs are composed from cells, which divide
and proliferate according to the body needs (e.g. when child
grow, or in the process of wound healing…).
Tumors result from unnecessary proliferation of
cells. Tumors can be benign or malignant. What makes tumors
malignant and cancerous is the ability of some of the tumor
cells to detach from the “tumor” masses, travel in the blood
stream or the lymphatic system, reside in other organs and
start dividing there. This process is called “metastasis”.
The type of cancer is determined according to its
origin: this means according to the organ from which the
unnecessary cell proliferation initiated. There are several
methods to determine the type of cancer:
1.
Clinical assessment:
a.
History taking: detailed history
from the patient and his relatives regarding the disease
symptoms is very important. The symptoms are usually
non-specific, but they help in directing the clinician to
the disease source. Symptoms that may help in assessing the
type of cancer include: changes in skin color (melanoma);
head and neck lumps (cancer of head and neck); changes in
voice (laryngeal cancer); convulsions (brain cancer); breast
lumps (breast cancer); hemoptysis, i.e. coughing up blood
(lung cancer or metastasis to the lung); rectal bleeding and
constipation (colon cancer); and vaginal bleeding (uterine
cancer).
b.
Physical
examination is a second and pivotal step. Physical
examination should include:
I.
Inspection: looking to the patient
is very important: Any skin discolorations, lumps, asymmetry
(e.g. breast asymmetry- including differences in the breast
skin texture) should be noted. Inspecting the patient while
moving will help identifying neurological deficits. Special
note should be given to the patient’s voice, as changes in
the voice quality may hint to the source of the disease
(e.g. laryngeal cancer).
II.
Palpation & percussion: palpating
the patient will help in identifying disease that is
difficult to assess by inspection only, and to further
assess lesions inspected by the examiner’s eyes. Palpating
lumps defines their size, consistency, and fixation to other
organs. Palpating and percussion the abdomen may detect
abdominal masses and evaluate the size of abdominal organs
(liver and spleen size) and their consistency. Palpation may
elicit pain; the location and quality of this pain allows
the clinician to further define the disease process.
III.
Auscultation: Is very important part
of the physical examination. For example obstruction of
bronchial airway (lung cancer) by cancer growth will results
in wheezes when auscultating above the diseased bronchus.
Auscultating the abdomen in a patient with bowel obstruction
due to intestinal cancer will gives “metallic sounds”.
2.
Radiological assessment:
a.
X- ray: Plain x- ray films may give
initial evaluation of caner disease and its complications. X
-ray is essential in evaluating lung cancer and metastasis
to the lung, bone lesions, and bowel obstructions due to
cancer.
b.
Mammography: It's a test that
utilizes x- rays to detect lesions in the breast.
c.
Ultrasonography: is a useful tool to
assess tumors. It is usually used to assess metastasis to
liver, blood flow in blood vessels and the presence of
thrombus, and can guide clinicians while performing biopsy
so that they can approach the desired location more
precisely. Trans-esophageal ultrasonography is helpful in
identifying pancreatic cancer. Trans-rectal ultrasound is
useful in identifying prostate cancer. Breast
ultrasonography is useful to define breast lesions detected
by mammography more precisely, and to guide biopsy from
suspicious lesions.
d.
Computerized Tomography (CT): CT
scans are very important for evaluating primary cancer and
its metastatic spread. Usually CT scans are enhanced with
contrast (iodine based) to get better visualization of the
cancerous spread (side effects of contrast include kidney
injury, and hence it should used with caution in patients
with preexisting kidney disease).
e.
Magnetic Resonance Imaging (MRI); Is
more expensive, and time consuming test. MRI is needed for
studying specific brain lesions, muscular and bone lesions,
and in some other situations that CT scan gives insufficient
information. Recently MRI is being utilized to examine
breasts, especially in young women with dense breast tissue
(where mammography is not usually inefficient).
3.
Biopsy: Biopsy is the process in
which a specimen from a suspected lesion/ lump/ mass is
taken. Biopsy may be open or closed. “Open biopsy” is
obtained through operation in which the surgeon makes
incision and approaches the desired lesion directly. “Close
Biopsy” is usually obtained under guidance of radiological
facility (ultrasound or CT); and the lesion is approached
via a fine needle (aspiration) or thicker needle that cuts
part of the lesion (Tru-cut biopsy). Once material from the
tumor is obtained, several tests may be performed; these
include pathological evaluation under microscope, molecular
cancer and genetic markers and microarray analysis.
4.
Pathological examination:
pathological examination is the diagnostic step that usually
supplies the final diagnosis of the disease. Following the
acquisition of the biopsy materials, it is sectioned and
stained with different methods and for different markers,
and viewed under microscope. According to the picture
obtained from the various staining, a diagnosis regarding
the nature of the disease and the type of cancer is
confirmed. In some highly malignant tumors, the origin of
the tumor cells can’t be identified even under microscopic
examination.
5.
Genetic markers. Molecular markers
may be studied from tumor specimens, and a microarray test
can be performed to elucidate the gene expression profile in
tumors. Tests for gene expression in tumor cells are
performed today, but usually to test a limited number of
genes (e.g. Oncotype Dx that test 21 genes). In the next
decade such tests will probably become more widespread, and
will incorporate much more genes.
The treatment of cancer includes multiple approaches:
Surgery, Chemotherapy, Radiotherapy, Antibodies, and tumor
vaccines.
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Jemal A, Siegel R, Ward E, Hao Y, Xu J, Murray T, Thun
MJ. Cancer statistics, 2008.
CA Cancer J Clin. 2008; 58: 71-96.
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