PATH's Cervical Cancer Prevention Action Planner

Screening for cervical precancer and cervical cancer

Screening women for cervical cancer and precancer, and treating those who test positive, has dramatically reduced cervical cancer mortality in wealthier countries over the past 50 years. However, the method used for screening—cytology, also known as the Pap smear—is too complex and expensive to be sustainable in most low-resource settings. Due to the lack of screening and treatment programs, about 85 percent of cervical cancer deaths now occur in the developing world.

Fortunately, new screening alternatives have been shown to be even more sensitive than Pap, and they are less expensive and provide results more rapidly. Visual inspection with acetic acid (VIA) and HPV DNA testing (the human papillomavirus, or HPV, is the main cause of cervical cancer) could for the first time make national, large-scale screening feasible in much of Africa, Asia, and Latin America. When detected early, most precancer can be treated with cryotherapy (freezing), a low-cost and simple procedure.

A wealth of free guidance documents are available to help program managers develop appropriate screening program strategies. The best of them are linked from this website and more can be found in the RHO Cervical Cancer library.

PATH is enthusiastic about the promise of the new screening and treatment methods and is committed to providing technical assistance to countries as they design and roll out new programs. If you would like to consult with PATH, contact us at rho@path.org.
This section of the Action Planner presents lessons learned from screening and treatment programs in low- and middle-income countries. The lessons and resources included here were generated through four projects implemented by PATH and partners:

  • The Alliance for Cervical Cancer Prevention (1999-2008)
  • START (2003-2007)
  • START-UP (2007-2013)
  • HPV Vaccines: Evidence for Impact (2006-2013)

For more information about these projects, visit the PATH website.

HPV and cervical cancer

Cervical cancer is a preventable disease affecting an estimated 530,000 women each year and leading to nearly 275,000 deaths.1 If current trends continue, by the year 2050 there will be more than one million new cases annually.

Research conducted over the past 30 years established that HPV is the primary cause of cervical cancer. HPV infection is very common; the majority of men and women become infected within a few years after becoming sexually active. The HPV types that cause most cervical cancer cases—about 70 percent worldwide—are types 16 and 18.2

Infection rates for women tend to be high during their teens and 20s. Most women spontaneously clear infections within a year or two, but in about 10 percent of infected women the infection persists, causing precancerous lesions to develop. If not detected through screening programs (and then treated), precancer develops into invasive cancer in about 10 percent of women with lesions (about 1 percent of all infected women).3

Fortunately, cervical cancer does not develop quickly. The progression from infection to precancer takes 10 to 20 years, and from precancer to cancer another 10 or 20 years. Therefore there are many opportunities to stop the disease before it becomes fatal.

Currently there are two ways to prevent cervical cancer: HPV vaccination to prevent infection, and cervical screening to detect disease early, when it is easier to cure.

HPV vaccines provide protection against the two HPV types that cause most cervical cancer, but not against all cancer-causing HPV types. Because the vaccines do not protect against all types, girls vaccinated now will need to be screened as adults to prevent disease caused by other HPV types. Screening also is crucial to protect the many women living in the world today who have already been infected, and for whom vaccination offers little benefit.

Most experts agree that countries should consider comprehensive cervical cancer prevention, offering programs for screening and treatment of adult women for precancer and cancer, as well as HPV vaccination of young adolescent girls. A good example of a comprehensive strategy for prevention is the Strategic Plan for Cervical Cancer Prevention and Control in Uganda.

PATH’s Outlook, Progress in Preventing Cervical Cancer: Updated Evidence on Vaccination and Screening, provides an overview of cervical cancer and current prevention options, including both vaccination and screening.

Screening for cervical precancer and cervical cancer

Ideally, all women over the age of 30 should be routinely screened for precancerous lesions of the cervix, but in reality only a small percentage of women are.4

Although cytology-based screening programs using Pap smears have been effective in the United States and other developed countries, most developing countries lack the infrastructure and trained personnel needed for that sort of technician-dependent, multi-visit testing approach. Therefore, in situations where health care resources are scarce, resources should be directed toward cost-effective strategies that are more affordable and for which quality can be assured. For this reason, PATH cervical cancer prevention programs generally have not focused on Pap, and we have not included a section on Pap in the Action Planner.

Studies have shown that the most efficient and effective strategy for secondary prevention of cervical cancer in low-resource settings is to screen using either HPV DNA testing or VIA, then to treat precancerous lesions using cryotherapy, as appropriate, and to refer women needing more complex care.4

VIA is a low-cost procedure that can be done in any clinic. VIA has been shown to be about as effective, or more effective, than Pap testing in identifying cervical cancer precursors, but Pap requires much more sophisticated equipment, training, and logistics systems. Lessons learned about VIA begin here.

HPV DNA testing—a high-tech solution—is more sensitive than either VIA or Pap, but current tests are expensive and require a laboratory. Fortunately, easier-to-use and less expensive HPV DNA tests soon will become available, and may revolutionize cervical cancer screening around the globe. Read more about lessons learned about HPV DNA testing.

Subsequent to screening using an HPV DNA test, VIA is still useful for treatment selection to identify those patients for whom cryotherapy is not appropriate.

While HPV DNA tests perform best (they have the highest sensitivity) when cervical mucus samples are used, those samples can be collected only during a pelvic examination. Unfortunately, providers trained to perform pelvic examinations often are in short supply in the developing world, as is the equipment needed for the exam (specula and gloves, for example).

However, data recently generated by PATH’s START-UP project suggest that HPV DNA collected from the vagina yields test results more sensitive than VIA or Pap smear, though slightly less sensitive than cervical specimens, and without the need for a pelvic exam. The sampling may be done by a provider, or, alternately, several studies have shown that women can be taught to use a soft brush to swab the vaginal wall near the cervix and to gather the sample themselves. Lessons related to vaginal sampling are here.

It should be noted that in developing countries, cervical cancer screening once, twice, or three times in a lifetime could have a significant impact on the lifetime risk of cervical cancer, compared with no screening.

Computer models using data related to five low- and middle-resource countries projected that screening women once in their lifetime, at the age of 35 years, with a one-visit or two-visit screening strategy involving VIA or HPV DNA testing, reduced the lifetime risk of cancer by approximately 25 to 36 percent. Relative cancer risk declined by about 70 percent after two screenings (at 35 and 40 years of age).5

Treatment of cervical precancer

Cryotherapy (freezing abnormal cervical tissue) has been shown to be a safe, effective treatment for the majority of cases of cervical precancer.

When conducted by a competent provider, cryotherapy results in cure rates of 75 to 85 percent. It requires some special equipment, but it is simpler than other methods for treating precancerous lesions.

For cases where cryotherapy is not appropriate, other treatment methods may be available at higher-level facilities, such as loop electrosurgical excision procedure (LEEP) or cold knife conization.
Lessons related to cryotherapy are here.

ACCP Key Findings on Screening and Treatment

The ten key findings below were published in this form by the Alliance for Cervical Cancer Prevention in 2009. The following year the authors published an expanded, peer-reviewed paper that summarized the evidence and rationale for these findings (see Additional Resources at right).

  1. Simply providing new screening and treatment technologies and approaches is not sufficient to ensure uptake and program success.
  2. In low-resource settings, the optimal age-group for cervical cancer screening to achieve the greatest public health impact is 30 to 39-year-olds.
  3. Although cytology-based screening programs using Pap smears have been shown to be effective in the United States and other developed countries, sustaining high-quality cytology- based programs is difficult in low-resource settings. Therefore, in settings where health care resources are scarce, they should be directed toward cost-effective strategies that are more affordable and for which quality can be assured.
  4. The most efficient and effective strategy for detecting and treating cervical cancer precursors in low-resource settings is to screen using either VIA or HPV DNA testing and then to treat using cryotherapy. This strategy is optimally achieved in a single visit and can be carried out by competent physicians and non-physicians, including nurses and midwives.
  5. The use of HPV DNA testing followed by cryotherapy results in a greater reduction in the incidence of cervical cancer precursors than the use of other screen-and-treat approaches.
  6. When conducted by competent providers, cryotherapy is a safe way of treating precancerous cervical lesions and results in cure rates of at least 85%.
  7. Unless cervical cancer is suspected, the routine use of an intermediate diagnostic step (such as colposcopy) between screening and treatment is generally not efficient and may result in reduced programmatic success and increased cost.
  8. Women, their partners, communities, and civic organizations must be engaged in planning and implementing services, in partnership with the health sector.
  9. For maximum impact, programs require effective training, supervision, and continuous quality improvement mechanisms.
  10. Additional work is needed to develop rapid, user-friendly, low-cost molecular tests and to improve cryotherapy equipment.

The WHO manual Comprehensive Cervical Cancer Control: A guide to essential practice is an excellent resource on both screening and treatment.

The RHO Cervical Cancer Library screening and treatment section has an extensive selection of free documents, tools, presentations, videos, and other resources related to cervical cancer screening and treatment.

References
1. Ferlay J, Shin HR, Bray F, Forman D, Mathers C, Parkin DM. Globocan 2008 V1.2, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 10. International Agency for Research on Cancer, 2010.
2. World Health Organization. Comprehensive cervical cancer control: a guide to essential practice. Geneva: World Health Organization; 2006.
3. PATH. Progress in Preventing Cervical Cancer: Updated Evidence on Vaccination and Screening. Outlook. 2010;27(2).
4. Sherris J, Wittet S, Kleine A, Sellors J, Luciani S, Sankaranarayanan R, et al. Evidence-based, alternative cervical cancer screening approaches in low-resource settings. International Perspectives on Sexual and Reproductive Health. 2009;35(3):147-54.
5. Goldie SJ, Gaffikin L, Goldhaber-Fiebert JD, Gordillo-Tobar A, Levin C, Mahé C, et al. Cost-effectiveness of cervical-cancer screening in five developing countries. New England Journal of Medicine. 2005;353(20):2158-68.
Photo: Jessica Fleming

Woman


Additional resources

Print version: Cervical cancer screening and treatment in low-resource settings (PDF, RHO Cervical Cancer website)

Watch videoScreening and Treatment of Precancerous Lesions video and transcript

Screening and treatment (RHO Cervical Cancer website)

World Health Organization: Comprehensive Cervical Cancer Control: A guide to essential practice (PDF)

Planning and Implementing Cervical Cancer Prevention and Control Programs: A Manual for Managers (PDF)

Evidence-Based, Alternative Cervical Cancer Screening Approaches in Low-Resource Settings

Strategic Plan for Cervical Cancer Prevention and Control in Uganda (PDF)

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