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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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