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What
is Cervical Cancer?
In general terms, CANCER is a group
of diseases that cause normal cells
(tissue) in the body to change normal
growth pattern to go out of control.
Most types of cancer cells form a lump
or mass called a tumor. When cells from
the tumor break away and travel to other
parts of the body through blood circulation
where they continue to grow, it is called
a malignant or cancerous tumor. Not
all tumors are cancerous. Benign tumors
are not cancerous and do not grow or
spread.
Most cancers are named after the part
of the body where the cancer first starts.
Cervical cancer in women begins in the
lining of the cervix. The cervix is
the lower part of the womb (uterus)
and connects the body of the uterus
to the vagina or birth canal.
What
is the incidence of Cervical Cancer
in Indian population?
The foremost common cancer afflicting
women of any age group is cervical cancer
in India. This is a preventable cancer,
if properly detected in the initial
stages. It has not been addressed as
a community problem in India as in the
western world.
There are nearly quarter of a million
cervical cancer cases reported in India
with nearly 40,000 new cases being added
every year. The age adjusted cervical
cancer incidence reported from some
of the important cities of India is;
Mumbai – 21, Bangalore – 26.4, Chennai
– 43.5, Delhi – 30.1, Bhopal – 24.3
and Barshi (Maharashtra) – 26.2 per
100,000.
Can
Cervical Cancer be Prevented?
Cancer of the cervix does not develop
suddenly. Generally it takes between
5 to 15 years of persistent infection,
and is usually preceded by a series
of changes to the cells of the cervix,
where cells begin to change from normal
to abnormal and then to cancer. Cervical
cancer is totally preventable if these
precancerous cell changes or lesions
are detected and treated early, before
cervical cancer develops. For some women
pre-cancerous changes may go away without
any treatment. Sometimes they also need
to be treated by simple surgery, chemo
or radiotherapy to keep them from changing
into true cancers. But by and large,
cervical cancer is totally preventable
even at the advanced clinical stages
like CIN 2 or 3.
What
causes cervical cancer?
Cervical Cancer is the first cancer
in women to be identified as being caused
almost exclusively by a virus. Recent
medical research has identified that
certain types (known as high-risk or
oncogenic types) of Human Papillomavirus
(HPV) cause cervical cancer if they
are persistently present in the genital
tract.
What
are the clinical symptoms of Cervical
Cancer?
About 30 HPV types are are known to
infect squamous epithelium of lower
genital tract resulting into two types
of diseases: condylomas or “cauliflower
warts” also called as External Genital
Warts (EGWs) and “flat warts” subclinical
or precancer disease.
The EGWs are most commonly seen by naked
eye and can also be felt as raised bumps
externally on the skin. If they are
too small, they can go even unnoticed.
However, EGWs are seldom known to be
progressing to cervical cancer.
In the event of precancer disease, which
may progress to frank cancers, some
of the following symptoms most often
occur with or without other clinical
reasons besides cervical cancer. These
include: bleeding during or after intercourse,
irregular vaginal bleeding between periods,
persistent abnormal or white discharge
with or without foul smell, itching
or burning sensation. It may be advisable
to look for other causes such as fungal
growth or irritation from soaps or spermicide
that may cause these symptoms in presence
of warts.
The EGWs or precancers are often treated
by chemical/ cytotoxic agents, cryotherapy,
Scissor excision, electrosurgery, laser
vaporisation or immunotherapies depending
upon involvement of infected tissue
or may surgically be treated in the
advance stages of cancer.
What
is Human Papillomavirus (HPV)?
Human papillomavirus (HPV) is a group
of viruses that infect the genital skin
cells. It is an extremely common viral
infection in both men and women and
is the leading cause of cervical cancer
and cervical disease. There are nearly
120 site-specific types of HPV that
affect various parts of the body. Of
these, 13 types have been identified
as the high-risk types of HPV that can
cause cells of the cervix in women to
begin to change from normal to abnormal
and then to cancer if they are present
in the cells of the cervix.
How
do you get a HPV infection?
HPV is an extremely common viral infection
that can infect the genital tract of
men and women who have ever had a sexual
encounter, with an estimated 80% of
sexually active people contracting it
at some point in their lives. But it
is equally uncommon that they will progress
to develop cervical cancer (only 1 to
2% of them).
Genital HPV infections are usually spread
by direct, skin-to-skin contact during
vaginal, anal or (rarely) oral sex with
someone who has this infection. Rarely,
infants can be infected by their mothers
during birth.
What
are the symptoms of an infection with
high-risk HPV?
Symptoms of a genital HPV infection
may include the development of genital
warts or changes to the cells of the
cervix. These symptoms can appear weeks,
months or even years after initial infection,
so it is possible to become infected
without being aware of it. Often there
are no overt symptoms at all presented
by the patient.
In most cases, the virus is harmless,
however if high-risk types of HPV are
present in the cervix they can cause
cells to begin to change from normal
to abnormal and then to cancer if these
changes are not detected and timely
treated.
How
can it be detected and prevented early
?
If detected early, cervical cancer is
totally preventable. Only when it reaches
epithelial invasive stage, chemotherapy,
radiation or surgery may be required
which can be difficult, painful, expensive
and may even be unsuccessful. Since
oncogenic HPV can be detected many years
before its progression to disease stage,
direct testing for HPV DNA is gaining
increasing appreciation in routine clinical
practice. Whereas detection of premalignant
disease is routinely done by Pap smear
and subsequently by colposcopy. These
methods have limited sensitivity, specificity
and even reproducibility. According
to Dr Pierre Vassilakos of Center for
Cytology and Clinical Pathology in Geneva,
"two thirds of Pap smear mistakes
occur due to sampling errors and one
third to the cytologists!"
Whereas Pap smear tells about the sub-cellular
changes in the epithelial tissue of
the cervix, HPV DNA Test reveals underlying
cause of the infection and provide vital
information about the state of progression
to the cervical disease. It has a very
high positive (PPV) and negative predictive
values (NPV). Studies have shown that
positive predictive value of HPV DNA
for detection of cervical intraepithelial
neoplasia (CIN), the advanced pre-cancerous
conditions, rises with age, whereas
that of cytology (Pap smear test) decreases.
Is
it possible to test for HPV?
Yes, Digene’s Hybrid Capture 2 HPV DNA
test can detect the presence of high-risk
HPV types (potentially responsible for
leading to cervical cancer) (and also
low-risk HPV types) even before there
are visible
changes to the cells of the cervix,
those may or may not pose associated
clinical symptoms by the patient. A
positive HPV test does NOT always mean
that you will develop cancer, but it
provides additional information to your
doctor about potential risk that may
lead to it, enabling your doctor to
manage you closely to prevent it from
progressing to it.
The HPV test also means that if you
are negative, you have a reassurance
of your knowing that your chance of
developing cervical cancer is almost
negligible for at least 5 to 15 years
(combined with negative Pap test).
How
is the HPV specimen collected for testing?
The specimen is collected in the same
way as for Pap test by your gynecologist
via a cervical brush to collect cells
from the cervix. The sample with the
cervical brush is placed in the tube
containing a liquid transport medium
for couriering to the following laboratories
closest to your location where the facility
for Hybrid Capture 2 test is available
Is a PCR test for HPV DNA as specific
as Digene’s HC2 for picking up high
grade disease ?
There are no standardized and well characterized
PCR test protocols available for picking
up high grade lesions clinically relevant
from cancer management point of view.
All that PCR does is to identify presence
or absence of HPV in the specimen but
that may or may not be clinical use.
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HPV
DNA Testing - Essential Facts
- HPV
is the major etiological
(causative) agent for
of cervical cancer
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- HPV
detection is associated
with minimum 100-folds
increased risk of high-grade
CIN (cervical intraepithelial
neoplasia)
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- Essentially
all women with high grade
CIN have detectable HPV
DNA
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- The
higher the grade of neoplasia,
greater the association
with carcinogenic HPV
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- HPV
DNA positive, Pap smear
normal women are at an
increased risk of subsequent
CIN within few year
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