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Cervical cancer is cancer of the cervix -- the
opening of the uterus, extending into the upper end of the
vagina. Some 12,000 American women will be diagnosed with
cervical cancer this year. Thanks to effective screening,
which can detect cervical precancers and cancers early, most
of them can be cured.
With the advent of widespread screening by a
vaginal smear test developed by George Papanicolaou in the
1950s (commonly known as the "Pap smear"), the number of deaths
from cervical cancer has fallen dramatically -- from more
than 35,000 per year to about 4,000 per year today.
A Slow-Growing, Treatable Cancer
Cervical cancer usually grows slowly over many
years. Before true cancer cells develop, the tissues of the
cervix undergo changes -- called dysplasia, or precancers
-- that a pathologist can detect in a Pap smear. These changes
range from mild dysplasia or cervical intraepithelial neoplasia
(CIN1) to moderate (CIN2) to high-grade lesions (CIN3). They
can also resemble cancer cells without invasion, also known
as carcinoma in situ.
If left untreated, these precancers have the
propensity to invade and become cancerous. Once they spread
beyond the borders of the cervix, they can invade tissues
more deeply, into either the vagina or the uterus, and ultimately
metastasize to other parts of the body.
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There are two main types of cervical cancer:
- Squamous Cell Carcinoma
The majority of cervical cancers -- 85 to 90 percent --
are squamous cell carcinomas.
- Adenocarcinoma
The remaining 10 to 15 percent of cervical cancers are adenocarcinomas.
Cancers that have features of both cell types
are known as mixed, or adenosquamous, carcinomas.
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The most significant risk factor for cervical
cancer is infection with the human papillomavirus (HPV), which
can be transmitted during sex.
Papillomaviruses have been known to cause cervical
dysplasia, or precancers, for more than two decades. More
recently, DNA from these viruses has been found to exist in
virtually all cervical squamous cell carcinomas (the most
common type of cervical cancer).
By avoiding the following known risk factors
for HPV infection, women can reduce their likelihood of developing
cervical cancer:
- early age at first sexual intercourse (15
years or younger)
- having a history of many sexual partners (more
than seven)
- smoking (which produces chemicals that can
damage cervical cells, making them more vulnerable to infection
and cancer)
- infection with HIV (which reduces the body's
ability to fight off HPV infection and early cancers)
Women without these risk factors rarely develop
cervical cancer. Although all women can help protect themselves
from disease by having their sexual partners use condoms,
condoms do not provide complete protection from HPV infection
because this virus (unlike HIV) can be spread by contact with
any infected area of the body.
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Cervical cancer, especially in its earliest stages,
often causes no symptoms. That's why it's so important to
see your doctor for regular screening with a Pap test.
When symptoms do occur, they may include the
following:
- pain or bleeding during or after intercourse
- unusual discharge from the vagina
- blood spots or light bleeding other than a
normal period
These symptoms can be caused by cervical cancer
or by a number of serious conditions, and should be evaluated
promptly by a medical professional.
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A Pap test is used to detect the possibility
of a cervical cancer or dysplasia (precancer).
Biopsy
If a Pap test shows an abnormality, your doctor
will perform a biopsy (by removing a sample of cervical tissue
for microscopic examination). A gynecologist will often use
a colposcope (a viewing tube attached to magnifying binoculars)
to find the abnormal area and remove a tiny section of the
surface of the cervix, which a pathologist will examine to
see if it contains precancer or cancer cells. He or she may
also perform a Schiller test, in which the cervix is coated
with an iodine solution. Iodine causes the healthy cells to
turn brown, while abnormal cells appear white or yellow.
Cone Biopsy
If the diagnosis isn't clear, a surgeon may remove
a slightly larger, cone-shaped piece of tissue (called a cone
biopsy). At Tata Memorial Centre, cone biopsies are often
performed by loop excision, in which an electrical current
is passed through a thin wire loop to remove the sample tissue.
Loop excision takes only about 10 minutes under local anesthetic.
The cone biopsy is also a treatment, and can completely remove
many precancers and early cancers. More than 90 percent of
cervical cancers can be halted with this technique without
further treatment.
Cytoscopy & Other Imaging Tests
If your doctor suspects that the cancer may have
spread beyond the cervix, you may have cytoscopy (examination
of the bladder using a lighted tube), proctoscopy (examination
of the rectum), a chest x-ray, or other imaging tests -- such
as a computerized tomography scan (CT scan) of the abdomen
and pelvis to check for metastatic disease, or magnetic resonance
imaging scan (MRI scan) of the pelvis to check the extent
of local disease.
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Options for treating cervical cancer depend chiefly
on the stage of disease -- the size of the cancer, the depth
of invasion, and whether the cancer has spread to other parts
of the body. The primary forms of treatment are surgery and
combined radiation therapy and chemotherapy.
Carcinoma In Situ
These cancers are preinvasive and can be treated
conservatively, sparing the uterus. Options for treatment
include
- laser surgery (in which a narrow beam of intense
light is used to kill the cancerous cells)
- loop excision (in which an electrical current
is passed through a thin wire loop to remove the cells)
- cone biopsy (to surgically remove a cone-shaped
piece of tissue containing the cancer)
These treatments are almost always effective
in removing precancers and stopping them from developing into
true cancers.
Early Cervical Cancer (Stages I-IIA)
For early cervical cancers that are confined
to the cervix, surgical options may include hysterectomy (removal
of the uterus), sometimes along with the tissue next to the
uterus. Lymph nodes from the pelvis are also removed and examined
for cancer cells. If the cancer is associated with "high-risk"
features -- such as involvement of the pelvic lymph nodes,
invasion of the lymph channels or blood vessels of the cervix,
or involvement of the tissue along the uterus -- doctors recommend
chemotherapy combined with radiation therapy.
Advanced Cervical Cancer (Stages IIB-IVA)
If cervical cancer has spread beyond the cervix
and into the surrounding pelvic tissues, surgery alone is
usually not an effective cure. Patients with this degree of
invasive cancer have traditionally also been treated with
radiation therapy (the use of x-rays or other high-energy
waves to kill cancer cells and shrink tumors), either alone
or in addition to surgery.
In recent years, however, there has been a major
shift in the treatment of advanced cervical cancer. Based
on the results of large clinical trials, the standard of care
for regionally advanced cervical cancer is now chemotherapy
combined with radiation therapy. The radiation therapy may
be delivered externally and/or internally (by placing an implant
to deliver radioactive material immediately around the cervix).
Stage IVB & Recurrent Cervical Cancer
For women whose cancer spreads beyond the pelvis
(into the lungs or liver, for example) or who have recurrent
disease, treatment is aimed at reducing cancer-related symptoms
in order to improve a patient's quality of life, and hopefully
to prolong her survival. Chemotherapy is the primary modality
of treatment for these patients, and several drugs are available
for treating these women.
For women whose disease recurs in the pelvis,
extensive surgery may be the only curative option and requires
a highly experienced multidisciplinary team.
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