What is the cervix?

The cervix, or the neck of the womb, and the womb are both parts of a female reproductive system. The female reproductive system consists of:

• Vagina
• Womb (uterus), which includes the cervix
• Ovaries.

Women have two ovaries, one on either side of the lower abdomen (pelvis). Each month one of the ovaries produces an egg. Each ovary is connected to the uterus by a tube called the Fallopian tube.
In between each menstrual period an egg travels down one of the fallopian tubes and into the uterus. They alternate - one month may be the left side, and the next month the right side. When the egg enters the womb its lining thickens in preparation; in case the egg is fertilized by a man's sperm. If fertilization does not occur the thickened lining of the uterus is shed - a period (menses) occurs.
The cervix is the opening from the uterus to the vagina. It is a tight muscle that is normally firmly shut, with a small opening to allow the sperm through and the flow from a menstrual period. During labor (childbirth) the cervix opens.

Types of cervical cancer

Ectocervix - flat cells - squamous cell cervical cancer

The ectocervix is the portion of the cervix that projects into the vagina, also known and the portio vaginalis. It is about 3 cm long and 2.5 cm wide. There are flat cells on the outer surface of the ectocervix. These fish scale-like cells can become cancerous, leading to squamous cell cervical cancer.
Squamous cells - flat cells that look like fish scales. The word comes from Latin "squama" meaning "the scale of a fish or serpent". Our outer-layer skin cells are squamous cells, as well as the passages of the respiratory and digestive tracts, and the linings of hollow internal organs.

Endocervix - glandular cells - adenocarcinoma of the cervix

The endocervix is the inside of the cervix. There are glandular cells lining the endocervix; these cells produce mucus. These glandular cells can become cancerous, leading to adenocarcinoma of the cervix.
Adenocarcinoma - any cancer that develops in the lining or inner surface of an organ.

Transformation zone

This is where cervical cells are most likely to become cancerous. The transformation zone is located around the opening of the cervix, leading on to the endocervical canal (narrow passageway running up the cervix into the uterus). During cervical screening doctors and nurses will focus on this area.

Causes of cervical cancer

Cancer is the result of the uncontrolled division of abnormal cells. Most of the cells in our body have a set lifespan; when they die new cells are produced to replace them. Abnormal cells can have two problems:

1. They do not die
2. They continue dividing.

This results in an excessive accumulation of cells which eventually form a lump - a tumor. Scientists are not completely sure why cells become cancerous. However, there are some risk factors which are known to increase the risk of developing cervical cancer. These risk factors include:

HPV (human papilloma virus)

Around 70% of cervical cancer cases are estimated to be caused by HPV.

Human papilloma virus infection is a sexually transmitted virus. There are over 100 different types of HPVs - 15 types can cause cervical cancer; probably 99% of them. In addition there are a number of types which can cause genital warts. It is estimated that HPV types 16 and 18 cause about 70% of cases cervical cancer while HPV types 6 and 11 cause 90% of genital warts.
Other HPV types can cause cervical intra-epithelial neoplasia (CIN) - the growth of abnormal cells on the surface of the cervix.

Many sexual partners, becoming sexually active early

Cervical cancer-causing HPV types are nearly always transmitted as a result of sexual contact with an infected individual. Women who have had many sexual partners generally have a higher risk of becoming infected with HPV, which raises their risk of developing cervical cancer. There is also a link between becoming sexually active at a young age and a higher risk of cervical cancer.
If a woman develops cervical cancer it does not mean she had several sexual partners, or became sexually active earlier than most other females. It is just a risk factor. Women who only ever had one sexual partner can develop cervical cancer.

Smoking

Smoking increases the risk of developing many cancers, including cervical cancer.

Weakened immune system

People with weakened immune systems, such as those with HIV/AIDS, or transplant recipients taking immunosuppressive medications have a higher risk of developing cervical cancer.

Certain genetic factors

Scientists at Albert Einstein College of Medicine of Yeshiva University found that women with certain gene variations appear to be protected against cervical cancer.

Long-term mental stress

A woman who experiences high levels of stress over a sustained period may be undermining her ability to fight off HPV and be at increased risk of developing cervical cancer it can cause, scientists at the Fox Chase Cancer Center reported.

Giving birth at a very young age

Women who gave birth before the age of 17 are significantly more likely to develop cervical cancer compared to women who had their first baby when they were aged 25 or over.

Several pregnancies

Women who have had at least three children in separate pregnancies are more likely to develop cervical cancer compared to women who never had children.

Contraceptive pill

Long-term use of some common contraceptive pills slightly raises a woman's risk.

Other sexually transmitted diseases (STD)

Women who become infected with chlamydia, gonorrhea, or syphilis have a higher risk of developing cervical cancer. Scientists at the Medical University of South Carolina found that HPV infections last longer if Chlamydia also is present.

Socio-economic status

Studies in several countries have revealed that women in deprived areas have significantly higher rates of cervical cancer, compared to women who live in other areas. Studies have also found higher rates in women of working age in manual jobs, compared to women in non-manual jobs. The most likely reason is a difference in the proportion of women who have regular screening. Scientists at King's College London found that some areas in South East England had rates that were three times higher than neighboring areas.