06 March 2008

cervical cancer

Cervical cancer: malignant cancer of the cervix uteri or cervical area. It may present with vaginal bleeding but symptoms may be absent until the cancer is in its advanced stages, which has made cervical cancer the focus of intense screening efforts using the Pap smear. In developed countries, the widespread use of cervical screening programs has reduced the incidence of invasive cervical cancer by 50% or more.
Treatment consists of surgery (including local excision) in early stages and chemotherapy and radiotherapy in advanced stages of the disease.
Human papillomavirus (HPV) infection is a necessary factor in the development of nearly all cases of cervical cancer. An effective HPV vaccine against the two most common cancer-causing strains of HPV has recently been licensed in the U.S. (see Vaccine section, below). These two HPV strains together are responsible for approximately 70%of all cervical cancers. Experts recommend that women combine the benefits of both programs by seeking regular Pap smear screening, even after vaccination.

Cervical cancer is a carcinoma, typically composed of squamous cells, and is similar in some respects to squamous cell cancers of the head and neck and anus. All three of these diseases may be associated with human papillomavirus infection.

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, single swollen leg, heavy bleeding from the vagina, leaking of urine or feces from the vagina, and bone fractures.

The American Cancer Society provides the following list of risk factors for cervical cancer: human papillomavirus (HPV) infection, smoking, HIV infection, chlamydia infection, dietary factors, hormonal contraception, multiple pregnancies, use of the hormonal drug diethylstilbestrol (DES) and a family history of cervical cancer
The most important risk factor in the development of cervical cancer is infection with a high-risk strain of human papillomavirus. The virus cancer link works by triggering alterations in the cells of the cervix, leading to the development of cervical intraepithelial neoplasia, leading to cancer.
Women who have many sexual partners (or who have sex with men or women who had many partners) have a greater risk.
More than 250 types of HPV are acknowledged to exist (some sources indicate more than 200 subtypes) Of these, 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),but even those may cause cancer. Types 16 and 18 are generally acknowledged to cause about 70% of cervical cancer cases. Together with type 31, they are the prime risk factors for cervical cancer.
Genital warts although caused by different HPV types have no relation to cervical cancer.
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, but not all women infected with HPV develop cervical cancer. Use of condoms does not always prevent transmission. Likewise, HPV can be transmitted by skin-to-skin-contact with infected areas. In males, HPV is thought to grow preferentially in the epithelium of the glans penis, and cleaning of this area may be preventative.
Despite the development of an HPV vaccine, some researchers argue that routine neonatal male circumcision is an acceptable way to lower the risk of cervical cancer in their future female sexual partners. Others maintain that the benefits do not outweigh the risks and/or consider the removal of healthy genital tissue from infants to be unethical as it cannot be reasonably assumed that a male would choose to be circumcised. There has not been any definitive evidence to support the claim that male circumcision prevents cervical cancer, although some researchers say there is compelling epidemiological evidence that men who have been circumcised are less likely to be infected with HPV. However, in men with low-risk sexual behaviour and monogamous female partners, circumcision makes no difference to the risk of cervical cancer

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