Cervical cancer is a malignant neoplasm arising from cells originating in the cervix. One of the most common symptoms of cervical cancer is abnormal vaginal bleeding, but in some cases there may be no obvious symptoms until the cancer has progressed to an advanced stage.
Human papillomavirus (HPV) infection appears to be involved in the development of more than 90% of cases. HPV vaccines are effective against two to four of the high risk strains of this family of viruses. Since the vaccines only cover some types of HPV, guidelines still recommend that women have regular Pap smear screening, even after vaccination.
Most cervical cancers are squamous cell carcinomas, arising in the squamous (flattened) epithelial cells that line the cervix. Adenocarcinoma, arising in glandular epithelial cells is the second most common type. Very rarely, cancer can arise in other types of cells.
Cancer screening using the Pap smear can identify precancerous changes in cervical cells. Treatment of high-grade changes can prevent the development of cancer in many cases. In developed countries, the widespread use of cervical screening programs has dramatically reduced the incidence of invasive cervical cancer.
Treatment usually consists of surgery (including local excision) in early stages, and chemotherapy and/or radiotherapy in more advanced stages of the disease. Five year survival rates in the United States are 68%.
Worldwide, cervical cancer is second most commom. and the fifth deadliest cancer in women.
Worldwide, in 2008, it was estimated that there were 473,000 cases of cervical cancer, and in 2010 225,000 deaths. Approximately 80% of cervical cancers occur in developing countries.
Signs and symptoms
The early stages of cervical cancer may be completely asymptomatic.
Vaginal bleeding, contact bleeding, or (rarely) a vaginal mass may indicate the presence of malignancy. Also, moderate pain during sexual intercourse and vaginal discharge are symptoms of cervical cancer. In advanced disease, metastases may be present in the abdomen, lungs or elsewhere.
Symptoms of advanced cervical cancer may include: loss of appetite, weight loss, fatigue, pelvic pain, back pain, leg pain, swollen legs, heavy bleeding from the vagina, bone fractures, and/or (rarely) leakage of urine or faeces from the vagina.
Infection with some types of human papilloma virus (HPV) is the greatest risk factor for cervical cancer, followed by smoking.
Other risk factors include human immunodeficiency virus.
Not all of the causes of cervical cancer are known, however, and several other contributing factors have been implicated.
Human papillomavirus type 16 and 18 are the cause of 75% of cervical cancer globally while 31 and 45 are the cause of another 10%.
Women who have many sexual partners (or who have sex with men who have had many other partners) have a greater risk.
Of the 150-200 types of HPV known,
15 are classified as high-risk types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, and 82), 3 as probable high-risk (26, 53, and 66), and 12 as low-risk (6, 11, 40, 42, 43, 44, 54, 61, 70, 72, 81, and CP6108).
Genital warts, which are a form of benign tumor of epithelial cells, are also caused by various strains of HPV. However, these serotypes are usually not related to cervical cancer. It is common to have multiple strains at the same time, including those that can cause cervical cancer along with those that cause warts. The medically accepted paradigm, officially endorsed by the American Cancer Society and other organizations, is that a patient must have been infected with HPV to develop cervical cancer, and is hence viewed as a sexually transmitted disease (although many dispute that, technically, it is the causative agent, not the cancer, that is a sexually transmitted disease), but most women infected with high risk HPV will not develop cervical cancer.Use of condoms reduces, but does not always prevent transmission. Likewise, HPV can be transmitted by skin-to-skin-contact with infected areas. In males, there is no commercially available test for HPV, although HPV is thought to grow preferentially in the epithelium of the glans penis, and cleaning of this area may be preventative.
Smoking has also been linked to the development of cervical cancer.
There are a few different ways that smoking can increase the risk of cervical cancer in women which can be by direct and indirect methods of inducing cervical cancer.A direct way of contracting this cancer is a female smoker has a higher chance of CIN3 occurring which has the potential of forming cervical cancer.
When CIN3 lesions lead to cancer, most of them have the assistance of the HPV virus, but that is not always the case which is why it can be considered a direct link to cervical cancer.
An indirect means of developing this cancer by smoking is that it can lead to human papillomavirus which can result in cervical cancer. Heavy smoking and long term smoking seem to have more of a risk of getting the CIN3 lesions than lighter smoking or not smoking at all.
Although smoking has been linked to cervical cancer, it aids in the development of HPV which is the leading cause of this type of cancer.
Also, not only does it aid in the development of HPV, but if the woman is already HPV-positive she is at an even greater likelihood of contracting cervical cancer.