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What is cervical cancer?

Cervical cancer is caused by the uncontrolled growth of cells in the cervix. The cervix is the narrowed bottom portion of a woman's uterus. Shaped like a cone, it connects the uterus to the vagina.

The vast majority of cervical cancers are caused by persistent infections with certain types of human papillomavirus (HPV). HPV is a very common sexually transmitted disease. While nearly all cervical cancers are caused by HPV, not all HPV strains cause cervical cancer. Those that cause cervical cancer are considered high-risk types.

Cervical cancer begins slowly. The earliest, precancerous changes cause the cells lining the inside or outside of the cervix to appear different from normal cervical cells. These atypical, precancerous cells are more likely to progress to cancer if left untreated. If the cells become cancerous, they are initially limited to the surface lining (in situ). Without treatment, the cancer cells can become invasive by growing into the supporting tissues of the cervix and can potentially spread to other body sites.

There are two primary types of cervical cancer. Squamous cell carcinomas, which occur in the flat squamous cells that cover the outside of the cervix, are the most common. They make up about 80-90% of cervical cancers. Most other cases are adenocarcinomas, rising from mucus-producing gland cells of the opening of the cervix (the endocervix). A few cervical cancers are mixtures of both types.

With early detection, cervical cancer is usually treatable by surgically removing the cancer. If early stage cancer has spread beyond the surface of the cervix, treatment may require a hysterectomy, radiation, or chemotherapy. Early treatment cures about 85-90% of women with cervical cancer. Given time, cervical cancer can spread (metastasize) to the rest of the uterus, the bladder, the rectum, and the abdominal wall. Eventually, it can reach the pelvic lymph nodes and metastasize further, invading other organs throughout the body. Cure rates decline as cervical cancer spreads, with extensive cervical cancer usually becoming fatal.

The American Cancer Society estimates that more than 12,900 women develop cervical cancer each year in the United States and about 4,100 die from the disease. Invasive cervical cancer was once a very common disease in the U.S. Since the introduction of the Papanicolaou (Pap) test, a screening tool that allows the detection of cancerous and precancerous changes in the cervix, rates of cervical cancer in the U.S. and other industrialized nations have dropped by as much as 70%. Tests to detect high risk types of HPV have also been developed and are included in screening regimens.

However, in certain populations of the U.S. and in developing nations where access to healthcare and screening programs are limited, cervical cancer is still a very serious concern. According to the World Health Organization, cervical cancer is the second most common type of cancer in women living in developing nations. In these countries, about 445,000 women are diagnosed with cervical cancer and approximately 270,000 die from it.

Accordion Title
About Cervical Cancer
  • Risk Factors

    HPV is one of the most common sexually transmitted infections in the United States. HPV includes a group of more than 200 related viruses that cause warts in a variety of places on the body, including the cervix. More than 40 types of HPV affect the genital tract and are easily spread through direct sexual contact of skin and mucous membranes. Nearly all cervical cancers are caused by HPV, but not all HPV strains cause cervical cancer. Some types of HPV cause non-genital warts and are not sexually transmitted.

    Cervical strains of HPV are divided into "high risk" and "low risk" categories based on their association with cervical cancer. Persistent infections with high risk types of human papillomavirus (HPV) cause almost all cervical cancers. About a dozen HPV strains, such as HPV 16, 18, 33, 35, and 39, are considered "high risk" because they are linked to an increased risk for cervical and vaginal cancer. Two HPV types, 16 and 18, cause 70% of all cervical cancers. HPV 6 and HPV 11, on the other hand, cause 90% of all genital warts but are considered "low risk" because they rarely lead to cancer.

    Women who are sexually active at an early age and have multiple partners, or have a partner who has had multiple partners, or has had partners with cervical cancer are at a greater risk for getting HPV. Individuals with HIV infection (AIDS) and/or suppressed immune systems are also at increased risk. Cigarette smoking may also raise risk because it suppresses the immune system and may damage the DNA in the cells of the cervix. Smokers are about twice as likely as nonsmokers to get cervical cancer.

  • Signs and Symptoms

    Precancerous changes in the cervix usually do not cause any symptoms.

    By the time a woman notices nonspecific symptoms, such as increased vaginal discharge and/or abnormal bleeding between menstrual periods or after intercourse, invasive cancer has usually developed and may have already spread to nearby tissues.

    There are many conditions other than cancer that can cause abnormal vaginal bleeding and discharge. It is important that a woman see her healthcare provider both to determine the cause of any symptoms she may have and for regular preventive screening even if she has no symptoms.

  • Tests

    Screening tests

    • Pap test: the Papanicolaou (Pap) test is widely used to screen for precancerous or cancerous changes in cervical cells. The earliest, precancerous changes cause the cells lining the inside or outside of the cervix to appear different from normal cervical cells. These changes, when present on a Pap test, are termed "atypical cells." Atypical cells are not entirely specific for a precancerous condition, however, and can temporarily appear in response to infections or irritation of the cervix lining. Precancerous cells can become more abnormal in appearance over time and are more likely to progress to cancer if left untreated. In Pap tests, these more abnormal (intermediate) cellular changes are called low-grade or high-grade squamous intraepithelial lesions [see the sidebar on Pap test terminology].
    • HPV DNA test: There are multiple DNA tests that can detect human papillomavirus (HPV) infections before cell abnormalities are evident, according to the National Cancer Institute. These tests work by screening for the DNA of different types of high-risk HPV in cervical cells. Some HPV DNA tests detect high-risk HPV without identifying the specific type of HPV. Others detect specific HPV types known to cause most HPV-related cancers.


    Recommendations

    Current guidelines from various organizations, including the American College of Obstetricians and Gynecologists (ACOG), the U.S. Preventive Services Task Force (USPSTF) and the American Cancer Society (ACS), on cervical cancer screening recommend the following:

    • Screening with a Pap test for women ages 21 to 29 every 3 years
    • Screening with a Pap test and HPV DNA test for women ages 30 to 65 every 5 years (preferable), or every 3 years with Pap test alone (also acceptable)


    Significant changes to these recommendations may be on the horizon, however. The Food and Drug Administration (FDA) approved an HPV DNA test as a primary screening tool for cervical cancer, meaning it may be used without a Pap test. Individual health organizations have yet to update their screening recommendations, but an expert panel issued interim (temporary) guidelines in 2015. These guidelines say that:

    • The HPV test may be offered to women aged 25 and older without a Pap test.
    • If initial results are negative, women should be screened again no sooner than 3 years.


    Women interested in this new option should talk to their healthcare provider. The interim guidelines acknowledge that more studies are needed to further evaluate the HPV test and its role in cancer screening. For example, there are still questions about whether age 25 is the best age to start offering it as a primary screening option and how often women should be screened.

    ACOG, USPSTF and ACS guidelines recommend more frequent screening for women with risk factors such as exposure to DES (diethylstilbestrol) in utero, previous diagnosis of a high-grade precancerous cervical lesion or cervical cancer, HIV infection, or a compromised immune system.

    Cervical cancer screening for women younger than 21, regardless of sexual activity, is not recommended because the incidence of cancer in this age group is very low. False-positive results may occur due to normal cell changes and are somewhat common. The false-positive results may generate unnecessary and costly treatment as well as emotional anxiety.

    These guidelines recommend against screening for cervical cancer for women over the age of 65 who have had negative results on adequate prior screening and do not have a history of cervical cell abnormalities known as CIN2+ or dysplasia within the last 20 years. Guidelines define adequate prior screening as 3 consecutive negative Pap tests or 2 consecutive negative HPV and Pap co-test results in the prior 10 years, with the most recent within 5 years.

    Diagnostic tests

    If a woman has positive screening results, the health practitioner may use one or both of the following tests:

    • Colposcopy: this follow-up test involves putting a vinegar-like solution on the cervix and checking it for abnormalities using a bright light and magnifying instrument. The colposcopy may include a Schiller test, which involves placing iodine on the cervix, causing normal cells to turn brown and abnormal cells to show up as white or yellow.
    • Biopsy: if abnormal areas are found on the cervix during colposcopy, the health practitioner will remove small pieces of tissue for examination by a pathologist. A biopsy and microscopic evaluation are the only way to tell for sure whether abnormal cells are cancerous, precancerous, or reactive for some other reason.
  • Stages

    If cancer is found, it will then be "staged." Staging is a careful and thorough examination and classification of how far the cancer has spread and what body organs are involved. Stages include:

    • Stage 0—the cancer is found only in the cells covering the cervix.
    • Stage I—the cancer has grown into (invaded) the cervix, but it is not growing outside the uterus.
    • Stage II—the cancer has grown beyond the cervix and uterus and may have spread to the upper vagina. It has not spread (metastasized) to the walls of the pelvis or the lower part of the vagina.
    • Stage III—the cancer has spread to the lower part of the vagina or the walls of the pelvis. It has not spread to lymph nodes or to other areas of the body.
    • Stage IV—the most advanced stage of cancer; it has spread to other areas of the body, such as the lungs, lymph nodes or bones.


    Staging is a very important part of the diagnostic process. Treatment options and patient prognosis depend in large part on the stage of the cancer.

  • Treatment and Prevention

    Treatment of cervical cancer depends on the stage of the disease. If the cancer is either limited to the lining of the cervix or contained within the cervix, then treatments generally include surgical removal of abnormal cells or cryotherapy (freezing abnormal cells or tissues) or laser technology.

    Interventions for more invasive cervical cancer may include surgery to remove the cervix and uterus (hysterectomy), additional surgery to remove other affected tissue and organs, radiation treatments to destroy any remaining cancerous cells, and/or chemotherapy.

    As methods, treatments, and therapeutic drugs are constantly evolving, women should talk to their healthcare providers and work with them as well as a gynecologic oncologist (a doctor who specializes in cancer of the reproductive organs) to choose a treatment plan that is best for them. Depending on the diagnosis, women may wish to talk to their healthcare providers about participating in a clinical trial.

    Vaccines prevent infections caused by those strains of HPV that most commonly cause cervical cancer. These vaccines protect against new HPV infections, but they do not treat existing infections.

    The U.S. Food and Drug Administration (FDA) has approved three vaccines that protect against HPV. All three vaccines are approved for use in girls and women 9 to 26 years of age, and the two Gardasil vaccines are approved for the prevention of genital warts in boys and men 9 through 26 years of age.

    • Gardasil® protects against HPV types 6, 11, 16 and 18. (Types 16 and 18 cause 70% of cervical cancers, while types 6 and 11 cause about 90% of genital warts.)
    • Gardasil 9 protects against the same HPV types as Gardasil plus 5 additional types that cause about 15% of cervical cancers.
    • Ceravix® protects against HPV types 16 and 18.


    Boys and men are recommended to get the vaccine to protect against HPV and to help prevent spread of infections to their sexual partners, thus reducing their female partners' risk of developing cervical cancer.

    The vaccines are given in three doses over a period of six months. The same vaccine should be used each time a dose is administered. They are considered safe but are most effective when given at younger ages and before initial exposure to the virus.

    The American Academy of Pediatrics (AAP) recommends that both girls and boys receive the HPV vaccine series when they are 11 to 12 years old. The vaccine is also recommended for men up to 21 and women up to 26 years of age who did not receive it when they were younger. AAP recommends that young people who are sexually active still receive the vaccination, as those already infected with one type of HPV infection may benefit from the protection against other types included in the vaccine.

    The vaccines do not protect against all cervical cancers, so routine screening is recommended even if a woman has received the vaccine.

    Cervical cancer may also be prevented by avoiding risk factors such as multiple sex partners, unprotected sex, and smoking. Early detection and treatment of precancerous areas found on the cervix may prevent them from developing into cancer. Screening for, and treating, precancerous lesions are also crucial to preventing cervical cancer.

View Sources

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.

Sources Used in Current Review

(Reviewed 2014 October 15). Cervical Cancer Overview. American Cancer Society. Available online at http://www.cancer.org/Cancer/CervicalCancer/OverviewGuide/cervical-cancer-overview-key-statistics. Accessed 6/16/15.

(2012 March). Screening for Cervical Cancer. U.S. Preventive Services Task Force. Available online at http://www.uspreventiveservicestaskforce.org/uspstf/uspscerv.htm. Accessed 6/16/15.

Moyer, VA on behalf of the U.S. Preventive Services Task Force. (2012 June 19). Screening for Cervical Cancer: U.S. Preventive Services Task Force Recommendation Statement. Annals of Internal Medicine, 156(5). Available online at http://www.annals.org/content/early/2012/03/14/0003-4819-156-12-201206190-00424.full. Accessed 6/16/15.

(Reviewed 2014 March 17). Cervical Cancer Prevention and Early Detection. American Cancer Society. Available online at http://www.cancer.org/acs/groups/cid/documents/webcontent/003167-pdf.pdf. Accessed 6/16/15.

(Reviewed 2015 February 19). HPV and Cancer. National Cancer Institute. Available online at http://www.cancer.gov/cancertopics/factsheet/Risk/HP. Accessed 6/16/15.

Mayo Clinic Staff. (2015 January 31). Cervical Cancer. Mayo Clinic. Available online at http://www.mayoclinic.org/diseases-conditions/cervical-cancer/basics/definition/con-20030522. Accessed 6/16/15.

Cervical Cancer Prevention (PDQ)(2015 April 9). National Cancer Institute. Available online at http://www.cancer.gov/types/cervical/patient/cervical-prevention-pdq#section/all. Accessed 6/16/15.

Boardman, C. H. (Updated 2014 August 15). Cervical Cancer. Medscape. Available online at http://emedicine.medscape.com/article/253513-overview. Accessed 6/16/15.

(Updated 2015 May 29). Cervical Cancer Treatment (PDQ). National Cancer Institute. Available online at http://www.cancer.gov/types/cervical/patient/cervical-treatment-pdq. Accessed 6/16/15.

Ramirez, P.T and Gershenson, D.M. (Copyright 2015). Cervical Cancer. Merck Manual. Available online at https://www.merckmanuals.com/home/women-s-health-issues/cancers-of-the-female-reproductive-system/cervical-cancer. Accessed 6/16/15.

(Reviewed 2014 September 9). Pap and HPV Testing. National Cancer Institute. Available online at http://www.cancer.gov/types/cervical/pap-hpv-testing-fact-sheet. Accessed 6/16/15.

(Updated 2015 January 1). Human Papillomavirus Vaccine. U.S. Food and Drug Administration. Available online at http://www.fda.gov/BiologicsBloodVaccines/Vaccines/ApprovedProducts/ucm172678.htm. Accessed 6/16/15.

(Reviewed 2014 September 17). The HPV DNA Test. American Cancer Society. Available online through http://www.cancer.org. Accessed 6/16/15.

Saslow, D. et al. (2012 March 14). American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer. CA: A Cancer Journal for Clinicians. Available online at http://onlinelibrary.wiley.com/doi/10.3322/caac.21139/full. Accessed 6/16/15.

Jemal A, et al. (2013 January 7). Annual Report to the Nation on the Status of Cancer, 1975-2009, featuring the burden and trends in human papillomavirus (HPV)-associated cancers and HPV vaccination coverage levels. Journal of the National Cancer Institute. Available online at http://jnci.oxfordjournals.org/content/early/2013/01/03/jnci.djs491.full. Accessed 6/16/15.

(2013 September). New Guidelines for Cervical Cancer Screening: Patient Fact Sheet. American College of Obstetricians and Gynecologists (ACOG). Available online at http://www.acog.org/-/media/For-Patients/pfs004.pdf?dmc=1&ts=20150618T1127599323. Accessed 6/16/15.

(2012 March 14). American Cancer Society. New Screening Guidelines for Cervical Cancer. Available online at http://www.cancer.org/Cancer/news/News/new-screening-guidelines-for-cervical-cancer. Accessed 6/16/15.

Barclay, L. (2015 January 9). New Guidance Recommends HPV DNA Test for Primary Screening. Medscape Medical News. Available online at http://www.medscape.com/viewarticle/837832. Accessed 6/16/15.

(Reviewed March 2015) World Health Organization. Human papillomavirus (HPV) and cervical cancer. Available online at http://www.who.int/mediacentre/factsheets/fs380/en/. Accessed August 2015.

Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

(2002 January 22, Updated). What you need to know about Cancer of the Cervix. National Cancer Institute [On-line information]. Available online at http://www.cancer.gov/cancer_information/doc_wyntk.aspx?viewid=1529727f-0309-4f59-aa5f-a17a761f10d9.

(2000 February 4). Cervical Cancer. Cervical Cancer Detailed Guide. American Cancer Society [On-line information]. Available online at http://www.cancer.org/eprise/main/docroot/CRI/content/CRI_2_4_7x_CRC_Cervical_Cancer_PDF.

CDC (2002). Cervical Cancer and Pap Test Information. The National Breast and Cervical Cancer Early Detection Program [On-line information]. Available online at http://www.cdc.gov/cancer/nbccedp/info-cc.htm.

MedlinePlus (2001 January 26, Updated). Cervical Cancer. MedlinePlus Health Information [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000893.htm.

Nuovo, J. et. al (2001 September 1). New Tests for Cervical Cancer Screening. American Family Physician (AAFP) [On-line journal]. Available online at http://www.aafp.org/afp/20010901/780.html.

Canavan, T., and Doshi, N. (2000 March 1). Cervical Cancer. American Family Physician (AAFP) [On-line journal]. Available online at http://www.aafp.org/afp/20000301/1369.html.

Screening for Cervical Cancer. WebMD Health [On-line information]. Available online at http://my.webmd.com/content/article/1680.50756. (Taken from http://odphp.osophs.dhhs.gov/pubs/GUIDECPS/text/CH09.txt)

Zoorob, R., et. al. (2001 March 15). Cancer Screening Guidelines. American Family Physician (AAFP) [On-line journal]. Available online at http://www.aafp.org/afp/20010315/1101.html.

(2004 Copyright). Human Papilloma Virus (HPV). American Cancer Society [On-line information]. Available online at http://www.cancer.org/docroot/cri/content/cri_2_6x_human_papilloma_virus_hpv.asp?sitearea=cri.

Bren, L. (2004 January February). Cervical Cancer Screening. FDA Consumer Magazine [On-line article]. Available online at http://www.fda.gov/fdac/features/2004/104_cancer.html.

(2004 Copyright). Human Papillomavirus (HPV). ARUP's Guide to Clinical Laboratory Testing [On-line testing information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_302a.jsp#3465668.

(2004 May 4). Revised Cervical Cancer Screening Guidelines Require Reeducation of Women and Physicians. ACOG [On-line news release]. Available online at http://www.acog.org/from_home/publications/press_releases/nr05-04-04-1.cfm?printerFriendly=yes.

(2004 Copyright). The High-Risk HPV Test: A Breakthrough in Cervical Cancer Screening. The HPVtest.com [On-line information from Digene Corportaion]. Available online at http://www.thehpvtest.com/factsheet.html.

(December 2009). American College of Obstetricians and Gynecology Practice Bulletin Number 109, Cervical Cytology Screening. PDF available for download at http://journals.lww.com/greenjournal/documents/PB109_Cervical_Cytology_Screening.pdf. Accessed December 2009.

(April 16, 2008) American Cancer Society. Cervical Cancer Overview: How many women get cervical cancer? Available online at http://www.cancer.org/docroot/CRI/content/CRI_2_2_1X_How_many_women_get_cancer_of_the_cervix_8.asp?sitearea=. Accessed July 2008.

National Cancer Institute. Cancer Advances in Focus, Cervical Cancer. Available online at http://www.cancer.gov/Templates/doc.aspx?viewid=CA5EF6E5-F688-4D1C-A64E-E999866BA508. Accessed June 2008.

National Cancer Institute. What You Need to Know About Cancer of the Cervix: Risk Factors. Available online at http://www.cancer.gov/cancertopics/wyntk/cervix/page5. Accessed June 2008.

National Cancer Institute. What You Need to Know About Cancer of the Cervix: Screening. Available online at http://www.cancer.gov/cancertopics/wyntk/cervix/page6. Accessed June 2008.

National Cancer Institute. What You Need to Know About Cancer of the Cervix: Diagnosis. Available online at http://www.cancer.gov/cancertopics/wyntk/cervix/page8. Accessed June 2008.

(March 26, 2008) American Cancer Society. Detailed Guide: Cervical Cancer, Can Cervical Cancer Be Prevented? Available online at http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_Can_cervical_cancer_be_prevented_8.asp?sitearea=. Accessed June 2008.

Montalto, N (January 2008). New Evidence-Based Screening Guidelines for Pap Tests. ACOG, Healthy Woman 2008. Available online at http://www.acog.org/acog_districts/dist_notice.cfm?recno=1&bulletin=2496. Accessed July 2008.

(June 6, 2006) US Food and Drug Administration. FDA Licenses New Vaccine for Prevention of Cervical Cancer and Other Diseases in Females Caused by Human Papillomavirus. FDA News. Available online at http://www.fda.gov/bbs/topics/NEWS/2006/NEW01385.html. Accessed July 2008.

(November 21, 2007) Zeller J, Lynm C, Glass R. Carcinoma of the Cervix. JAMA. 2007;298(19):2336. PDF available for download at http://jama.ama-assn.org/cgi/reprint/298/19/2336.pdf. Accessed July 2008.

(Reviewed/updated April 2008) American Academy of Family Physicians. Pap Smears. Available online at http://familydoctor.org/online/famdocen/home/women/reproductive/gynecologic/138.html. Accessed July 2008.

American Cancer Society. Cervical Cancer Overview. Available at http://www.cancer.org/Cancer/CervicalCancer/OverviewGuide/cervical-cancer-overview-key-statistics. Last reviewed February 8, 2012. Accessed March 23, 2012.

World Health Organization. Sexual and Reproductive Health: Cancer of the Cervix. Available online at http://www.who.int/reproductivehealth/topics/cancers/en/. Accessed March 23, 2012.

Press release. FDA Approves New Indication for Gardasil to Prevent Genital Warts in Men and Boys. Available online at http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm187003.htm. Issued October 16, 2009. Accessed March 23, 2009.

U.S. Preventive Services Task Force. Screening for Cervical Cancer. Release Date: March 2012. Available online at http://www.uspreventiveservicestaskforce.org/uspstf/uspscerv.htm. Accessed March 2012.

Moyer, VA on behalf of the U.S. Preventive Services Task Force. Screening for Cervical Cancer: U.S. Preventive Services Task Force Recommendation Statement. Annals of Internal Medicine, March 6, 2012, 156(5). Available online at http://www.annals.org/content/early/2012/03/14/0003-4819-156-12-201206190-00424.full. Accessed March 2012. 

American Cancer Society. New Screening Guidelines for Cervical Cancer. Article date: March 14, 2012. Available online at http://www.cancer.org/Cancer/news/News/new-screening-guidelines-for-cervical-cancer. Accessed March 2012.

American College of Obstetricians and Gynecologists (ACOG). Cervical cytology screening. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2009 Dec. 12 (ACOG practice bulletin; no. 109). Available online at http://www.guideline.gov. Accessed March 23, 2012

National Cancer Institute. Fact Sheet. HPV and Cancer. Available online at http://www.cancer.gov/cancertopics/factsheet/Risk/HPV. Accessed March 23, 2012.

National Cancer Institute.Treatment Options by Stage. Available online at http://www.cancer.gov/cancertopics/pdq/treatment/cervical/Patient/page5. Accessed March 23, 2012 .

(December 19, 2011) Centers for Disease Control and Prevention. HPV and Men—Fact Sheet. Available online at http://www.cdc.gov/std/HPV/STDFact-HPV-and-men.htm. Accessed June 2012.

Reuters. Wait longer between Pap tests, doctors say. October 22, 2012. Available online at http://www.reuters.com/article/2012/10/22/health-cancer-papsmear-idUSL3E8LM84D20121022. Accessed November 2012.

ACOG. Ob-Gyns Recommend Women Wait 3 to 5 Years Between Pap Tests. October 22, 2012. Available online at http://www.acog.org/About_ACOG/News_Room/News_Releases/2012/Ob-Gyns_Recommend_Women_Wait_3_to_5_Years_Between_Pap_Tests. Accessed November 2012.