Cervical cancer is cancer of the cervix, the lower part of the uterus that opens
into the birth canal. It is one of the most common types of cancer in women worldwide,
but also one of the most preventable, thanks to early detection with Pap tests.
The cervix has 2 major cell types: flat squamous cells lining the outer part, and column-shaped
glandular cells covering the inside of the cervical canal. Both types can become cancerous
but squamous cell carcinomas are much more common. Cancer usually starts in the zone where the two
cell types meet, known as the transformation zone. Virtually all cervical cancers are caused by
human papillomaviruses, or HPVs. There are over a hundred different types of HPV, some of which pose
higher risks than others. About 70% of all cases are caused by just two types: HPV-16 and HPV-18.
Two proteins produced by HPV, known as E6 and E7, interfere with cell functions that normally
prevent excessive cell division. This causes the cells to grow in an uncontrolled manner.
HPV is sexually transmitted and is very common, but in most women,
HPV infections resolve on their own and do not cause cancers. Factors that may increase the
risk of persistent HPV infections include weakened immune system, other sexually transmitted diseases
and smoking. Chances of developing cervical cancer also increase with having many children
and long-term use of birth control pills. Early-stage cervical cancer generally
produces no symptoms. Advanced-stage disease may cause abnormal or irregular vaginal bleeding,
pelvic pain, or unusual vaginal discharge. Early detection is the key to prevent cervical
cancer. Cervical cancer screening may include pap tests alone, or in combination with HPV DNA
tests. In a pap test, cells are scraped from the cervix and examined for pre-cancerous changes,
known as cervical intraepithelial neoplasia, or cervical dysplasia. These morphological
changes can range from mild to severe. If the results are abnormal, the test is repeated again
after 6 months or a year to monitor the condition. Additional diagnostic tests may also be performed.
In most cases, mild dysplasia resolves on its own and a follow-up pap test is all that is
required to confirm. In a small number of cases, these abnormal cells may develop into cancer,
but they usually take years to do so, which allows plenty of time for treatment
when detected early. In the US, a pap test is recommended every 3 years, from the age of 21,
or every 5 years if combined with an HPV test. Treatment options for cervical cancer include
surgery, radiation, chemotherapy or a combination of these. Early-stage cervical cancer is typically
treated with surgical removal of the uterus. This option is the most effective in preventing
cancer from coming back and is usually preferred when patients do not need to maintain fertility.