Varuna Srinivasan, MBBS, MPH & Jared Hirschfield, National Center for Health Research
Cervical cancer is cancer in the cells lining the cervix, the narrow passage between the uterus and vagina. This cancer is usually diagnosed in women between the ages of 35 and 44.1 Each year in the United States, approximately 13,000 women are diagnosed with cervical cancer and 4,700 women die from cervical cancer.1 With regular screening and follow-up, however, cervical cancer is one of the easiest cancers to prevent and is highly curable if found early.
Almost all cases of cervical cancer are caused by the human papillomavirus (HPV), most commonly by two high-risk strains called HPV-16 and HPV-18.2 However, nine out of ten HPV infections go away on their own without treatment and do not result in cancer or any other health problems.
In addition to exposure to HPV-16 and HPV-18, there are other factors that put you at an increased risk for cervical cancer, including:3
- Multiple sexual partners and sexual intercourse at an early age
- In utero exposure to DES, a hormonal medication banned by the FDA in 1975
- Long-term use of oral contraceptive pills
- Multiple pregnancies
- Other sexually transmitted diseases, such as HIV and chlamydia
- Poor dietary habits or low consumption of fruits and vegetables
- Family history of cervical cancer
Screening for cervical cancer
There are three screening methods to help detect and diagnose cervical cancer early when it is easy to treat. These include Pap smears, HPV tests, and a combination of both Pap smears and HPV tests (cotesting).
The United States Preventive Services Task Force (USPSTF) is a group of experts that recently updated its recommendations for cervical cancer screening. They recommend no screening for women under 21 and a Pap smear every three years for women 21-29 years old. For women between the ages of 30 and 65, they recommend a Pap smear every 3 years or a high-risk HPV (hrHPV) test every 5 years. As an “alternative,” USPSTF recommends Pap smear-HPV cotesting every 5 years. They do not recommend any screening for women over 65 or women who have had a hysterectomy.4
USPSTF Cervical Cancer Screening Recommendations (Updated August 2018)4
|Women younger than 21 years
|Women aged 21 to 29 years
|Women aged 30 to 65 years
|Women older than 65 years
|Women who have had a hysterectomy*
*with removal of the cervix
What is a Pap smear?
A Pap smear is used to evaluate abnormal cells in the cervix that can be diagnosed as pre-cancer or as cervical cancer. When a woman undergoes a Pap smear, a doctor or nurse collects cells from the outer layer of the cervix with a special stick, swab or a soft brush. The sample is then sent to a lab, where a pathologist checks for signs of abnormal cells. If the test is “positive,” the woman has abnormal cells, and those are graded, from least severe to most severe, as ASC-US (atypical squamous cells of undetermined significance), LSIL (low-grade squamous intraepithelial lesion), ASC-H (atypical squamous cells, cannot rule out HSIL), or HSIL (high-grade squamous intraepithelial lesion). Based on this grade, your doctor might recommend further testing, such as a colposcopy (a procedure in which the cervix is examined with a magnifying instrument) or a cervical biopsy.
What is an hrHPV test?
In a high-risk HPV test, also known as an hrHPV test, cells collected from the cervix are tested for the presence of HPV-16 and HPV-18, types of HPV that are most likely to cause cervical cancer. Keep in mind, however, that unlike the Pap smear, the HPV test does not tell you whether you have cervical cancer or are likely to develop cervical cancer. Instead, it can only tell you if you currently have the virus that can be dangerous now or in the future.2
Which screening test is better?
The goal of both screening tests is to detect cervical cancer as early as possible while keeping the risks to women at a minimum. Pap smears and HPV testing accomplish this in different ways. Whereas Pap smears identify abnormal cells currently in your body, HPV testing indirectly measures your risk of precancer or cancer by identifying the presence of the virus. HPV testing itself is not harmful, but testing for a virus that usually goes away by itself can lead to a very high rate of false positives.5 This means that people who may never actually develop cervical cancer may undergo expensive and painful invasive procedures to test for cancer and will experience the stress and fear of a cancer diagnosis.
Women with more than one sexual partner in recent years or whose sexual partner has other sexual partners are especially likely to have HPV. For that reason, the National Center for Health Research (NCHR) recommends a Pap smear every 3 years rather than an hrHPV test for these women. Alternatively, NCHR recommends combining a Pap smear and hrHPV test every 5 years. In addition, we recommend that women over 65 who have recently had more than one sexual partner or have had a sexual partner who has had other sexual partners should continue regular Pap smears until age 75.
Bottom line: What is the best screening option for screening and how can cervical cancer be prevented?
The USPSTF recommendations are based on assumptions about the sexual activity of women at different ages. On average, women over 30 tend to have fewer sexual partners and more monogamous relationships than women under 30, and women over 65 have even fewer. However, the National Center for Health Research recommendation is focused more on the number of sexual partners, and the fact that women in a monogamous relationship do not necessarily know if their sexual partner has had any other sexual partners. For that reason, we recommend Pap smears every 3 years or Pap smear-hrHPV cotesting every 5 years as the preferred methods of cervical cancer screening for most sexually active women aged 30 to 75. Pap smears directly determine the presence of cancerous or precancerous cells in your body. Cotesting can provide the added benefit of identifying high-risk HPV infection and allow for more vigilant follow-up if HPV-16 or HPV-18 is diagnosed.
In addition to monogamous relationships, women can reduce their chances of cervical cancer by using condoms. Other ways of reducing the risk include regular screening and follow-up with your physician, exercising, maintaining a healthy weight and balanced diet, and avoiding tobacco products.
 American Cancer Society. “Key Statistics for Cervical Cancer.” 04 January 2018. https://www.cancer.org/cancer/cervical-cancer/about/key-statistics.html.
 Centers for Disease Control. “Cervical Cancer.” December 2016. https://www.cdc.gov/cancer/cervical/pdf/cervical_facts.pdf.
 American Cancer Society, What Are the Risk Factors for Cervical Cancer?, www.cancer.org, https://www.cancer.org/cancer/cervical-cancer/causes-risks-prevention/risk-factors.html, October 3rd 2018
 US Preventive Services Task Force. “Screening for Cervical Cancer US Preventive Services Task Force Recommendation Statement.” JAMA 2018;320(7):674–686. doi:10.1001/jama.2018.10897
 Rebolj, M. et al. “The Problem of False-Positive Human Papillomavirus DNA Tests in Cervical Screening.” Current Pharmaceutical Design (2013) 19: 1439. https://doi.org/10.2174/1381612811319080011