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CANCER DIAGNOSIS: THE BIOPSY
How Is Cancer Diagnosed?
Cancer is diagnosed by physically removing a sample (tissue, cells, or
fluid) of a
suspected tumor and examining this material under a microscope.
This procedure is called a biopsy. Microscopic examination of biopsy
samples is the ONLY way that a positive diagnosis of cancer can be made. A
specialist physician called a pathologist performs this examination. After careful evaluation, a benign (non-cancerous) or malignant (cancerous) diagnosis can usually be established. The pathologist then prepares a written report that is sent to your doctor, and upon which treatment is based.
Note: Certain biopsy techniques, especially cytology
procedures, needle biopsies, and core biopsies, sometimes remove such
small quantities of cells or tissue that they can be inadequate to make a
positive cancer diagnosis. While these techniques are generally
accurate and reliable, situations where the needle misses the tumor can
cause the biopsy to appear benign when in fact a cancerous tumor really
does exist ('false negative'). In this situation, it may be necessary to repeat the biopsy procedure. This possibility should be discussed with your doctor.
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Types of Biopsy Procedures:
- BONE MARROW BIOPSY
- Bone marrow is located in the center of many bones, and is responsible
for producing blood cells. This test is used for the diagnosis and staging of cancers
involving the blood cells. These include the various forms of
lymphoma and leukemia. Bone marrow biopsies are also used to look
for metastatic disease (i.e. invasion of the bone marrow by tumor cells
originating elsewhere in the body).
- CONE BIOPSY
- In this specialized technique, a small cone-shaped sample of tissue is
removed from the inner surface of the cervix (opening of uterus). Cone biopsies are used
to diagnose cervical cancer in patients with either an abnormal
PAP smear or an abnormal cervical punch biopsy.
- CT- or ULTRASOUND-DIRECTED NEEDLE BIOPSY
- If a suspected tumor is
inaccessible or located deep within the body, it may be
necessary to use special x-ray (CT scan) or ultrasound imaging in
order to precisely position a needle through which a biopsy sample
can be removed.
- CYTOLOGY SMEARS
-
In a cytology smear individual cells are removed using
either a very thin needle or by scraping a surface with an
instrument. The cells obtained are carefully smeared onto a glass
slide, colored with special stains, and then interpreted by a
cytopathologist (a pathologist with special training in the study of
cells).
- ENDOSCOPIC BIOPSY
- An endoscopic
biopsy is a general term that refers
to biopsy samples obtained by using a special fiber-optic instrument
(with miniature forceps on the end) that can be passed into hard-to-
reach areas of the body. Endoscopic biopsies are commonly used to
take biopsy samples from the stomach ("gastroscopy"), the colon ("colonoscopy"), the
bladder ("cystoscopy"), the lungs ("bronchoscopy") or the joints
("arthroscopy").
- EXCISIONAL BIOPSY
- An excisional biopsy is a surgical procedure in which an
entire tumor, along with a small rim (or margin) of normal tissue
around it, is removed. This technique is commonly used to remove
relatively small and easily accessible masses.
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- FINE NEEDLE ASPIRATION (FNA)
- In this procedure, a very thin
needle attached to a syringe is used to extract (aspirate) individual or
small clusters of cells. This technique is used alone when the mass
can be clearly felt (palpated) through the skin. For subtle or deep
lesions that cannot be felt through the skin, this procedure is used
along with x-ray or ultrasound guidance. Since FNA only
removes individual cells or very small clusters of cells, it is usually
performed by a cytopathologist (a pathologist with special training in
the examination of very small quantities of cells).
- FROZEN SECTION
- During surgery, it may be necessary to determine
whether a tumor is benign (non-cancerous) or malignant (cancerous).
A frozen section is a rapid process that allows the pathologist to give the
surgeon an on-the-spot diagnosis, while the patient is still in the operating room. In this procedure, the surgeon removes a sample of
tissue and submits it to the pathologist. Microscopic slides are then prepared
and examined by a pathologist. The entire procedure takes 10-12 minutes. The
pathologist discusses his findings with the surgeon who can then determine the
best surgical procedure to perform.
- INCISIONAL BIOPSY
- Refers to a surgical technique used to sample a large,
sometimes inaccessible mass. The surgeon cuts into the mass and
removes a small wedge or slice. This method is used to establish a
definitive diagnosis of cancer, before doing major surgery to remove a
large mass.
- LYMPH NODE BIOPSY
- The lymph nodes are small, round structures found
throughout the body that drain and filter body fluids. They can
become involved and enlarged in many types of disease. These
include cancers such as lymphoma or
leukemia, as well as metastatic cancer. Lymph
node biopsy is also used to "stage" various types of cancer to
determine how far the disease has spread.
- NEEDLE (CORE) BIOPSY
- In a needle biopsy, a large diameter (large-bore)
needle is inserted into a mass to extract one or many "cores" of tissue.
The procedure can be performed in a doctor's office or hospital and
results are usually available in 24-48 hours.
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- PAP SMEAR
- PAP smears are routinely used to examine cells from the
surface of the cervix. In this procedure, the surface of the cervix is
scraped with a spatula-shaped instrument to obtain a sample of cells.
These cells are then stained and examined under a microscope by a
cytopathologist who makes a diagnosis.
- PUNCH BIOPSY
- This technique is used to obtain a deep core of skin and
underlying tissue. The instrument is a hollow tube that is rotated into
the skin until a cylinder (core ) of tissue from the proper depth is
obtained. This procedure is also used to examine
the cervix following an abnormal PAP smear.
- SHAVE BIOPSY
- A shave biopsy is a method of obtaining a biopsy sample
from a skin lesion. A scalpel is used to literally
shave off the surface of a lesion. This method is
commonly used to evaluate pigmented moles (suspected melanomas),
or other tumors involving the skin. If the pathologist determines that
the lesion is malignant (cancerous), another procedure will be
necessary to remove the remaining portion of the tumor.
- STEREOTACTIC BIOPSY
- This is a specialized radiology technique used to
evaluate masses that are either too small to be felt directly through the
skin or located in an inaccessible part of the body. It is most
frequently used to evaluate breast masses, but other parts of the body
can also be sampled using this procedure. With sophisticated, three-
dimensional computerized x-ray equipment, the suspicious mass is
localized on coordinates and then a small incision is made directly
above it. A radiologist or surgeon then uses a needle to extract the
biopsy sample, which is sent to a pathologist for diagnosis.
- WIRE LOCALIZATION BIOPSY
-
This is a specialized procedure used for small or
non-palpable breast masses. Using x-ray or ultrasound guidance, the
mass is located and, under anesthesia, a thin wire is carefully inserted
into the suspicious area. The surgeon uses the tip of the wire as
a guide to locate and remove a sample from the area in question.
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