Cervical cancer primary prevention
|
Cervical cancer Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Cervical cancer primary prevention On the Web |
|
American Roentgen Ray Society Images of Cervical cancer primary prevention |
|
Risk calculators and risk factors for Cervical cancer primary prevention |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [6]
Overview
Prevention of cervical cancer includes a comprehensive approach involving awareness, screening, and usage of preventative vaccinations.
Prevention
Awareness
According to the US National Cancer Institute's 2005 Health Information National Trends survey, only 40% of American women surveyed had heard of human papillomavirus (HPV) infection and only 20% had heard of its link to cervical cancer.[1] In 2006 an estimated 10,000 women in the US will be diagnosed with this type of cancer and nearly 4,000 will die from it.[2]
Screening
The widespread introduction of the Papanicolaou test, or pap smear for cervical cancer screening has been credited with dramatically reducing the incidence and mortality of cervical cancer in developed countries.[3] The pap smear suggests the presence of cervical intraepithelial neoplasia (premalignant changes in the cervix) before a cancer has developed, allowing for further workup. Recommendations for how often a Pap smear should be done vary from once a year to once every five years. The American Cancer Society recommends that cervical cancer screening should begin approximately three years after the onset of vaginal intercourse and/or no later than twenty-one years of age.[4] If premalignant disease or cervical cancer is detected early, it can be treated relatively noninvasively, and without impairing fertility.
The HPV test is a newer technique for cervical cancer screening which detects the presence of human papillomavirus infection in the cervix. It is more sensitive than the pap smear (less likely to produce false negative results), but less specific (more likely to produce false positive results) and its role in routine screening is still evolving. Since more than 99% of invasive cervical cancers worldwide contain HPV, some researchers recommend that HPV testing be done together with routine cervical screening (Walboomers et al, 1999). But, given the prevalence of HPV (around 80% infection history among the sexually active population) others suggest that routine HPV testing would cause undue alarm to carriers.
Vaccination
Merck & Co. has developed a vaccine against four strains of HPV (6,11,16,18), called Gardasil™. It is now on the market after receiving approval from the US Food and Drug Administration on June 8, 2006.[5] Gardasil is targeted at girls and women of age 9 to 26 because the vaccine only works if given before infection occurs; therefore, public health workers are targeting girls before they begin having sex. The use of the vaccine in men to prevent genital warts and interrupt transmission to women is initially considered only a secondary market. The high cost of this vaccine has been a cause for concern. Gardasil has also been approved in the EU.[6]
GlaxoSmithKline has developed a vaccine called Cervarix™ which has been shown to be 100% effective in preventing HPV strains 16 and 18 and is 100% effective for more than four years.[7] These strains together cause about 70% of cervical cancer cases. Cervarix should be approved by year's end.[8][9]
Neither Merck & Co. nor GlaxoSmithKline invented the vaccine. The vaccine's key developmental steps are claimed by the National Cancer Institute in the US, the University of Rochester in New York, Georgetown University in Washington, DC, and the Queensland University in Brisbane, Australia. Both Merck & Co. and GlaxoSmithKline have licensed patents from all of these parties.[10]
Prognosis
Prognosis depends on the stage of the cancer. With treatment, 80 to 90% of women with stage I cancer and 50 to 65% of those with stage II cancer are alive 5 years after diagnosis. Only 25 to 35% of women with stage III cancer and 15% or fewer of those with stage IV cancer are alive after 5 years.
According to the International Federation of Gynecology and Obstetrics, survival improves when radiotherapy is combined with cisplatin-based chemotherapy.[11]
As the cancer metastasizes to other parts of the body, prognosis drops dramatically because treatment of local lesions is generally more effective than whole body treatments such as chemotherapy.
Interval evaluation of the patient after therapy is imperative. Recurrent cervical cancer detected at its earliest stages might be successfully treated with surgery, radiation, chemotherapy, or a combination of the three. Thirty-five percent of patients with invasive cervical cancer have persistent or recurrent disease after treatment.[12]
Average years of potential life lost from cervical cancer are 25.3 (SEER Cancer Statistics Review 1975-2000, National Cancer Institute (NCI)). Approximately 4,600 women were projected to die in 2001 in the US of cervical cancer (DSTD), and the annual incidence was 13,000 in 2002 in the US, as calculated by SEER. Thus the ratio of deaths to incidence is approximatley 35.4%.
Regular screening has meant that pre cancerous changes and early stage cervical cancers have been detected and treated early. Figures suggest that cervical screening is saving 5,000 lives each year in the UK by preventing cervical cancer.[13]
References
- ↑ "Most women unaware about HPV (MSNBC)".
- ↑ [1]
- ↑ [2]
- ↑ Saslow D, Runowicz CD, Solomon D; et al. (2002). "American Cancer Society guideline for the early detection of cervical neoplasia and cancer". CA: a cancer journal for clinicians. 52 (6): 342–62. PMID 12469763.
- ↑ [3]
- ↑ BBC EU approves cervical cancer jab 22 September 2006
- ↑ [4]
- ↑ The Grand Rapids Press About the cervical cancer vaccine 17 August 2006
- ↑ BBC Cancer jab 'stops 75% of deaths' 4 September 2006
- ↑ [5]
- ↑ Committee on Practice Bulletins-Gynecology (2002). "ACOG practice bulletin. Diagnosis and treatment of cervical carcinomas, number 35, May 2002". Obstetrics and gynecology. 99 (5 Pt 1): 855–67. PMID 11978302.
- ↑ "Cervical Cancer". Cervical Cancer: Pathology, Symptoms and Signs, Diagnosis, Prognosis and Treatment. Armenian Health Network, Health.am.
- ↑ "Cervical cancer statistics and prognosis". Cancer Research UK. Retrieved 2007-03-24.