On this page:
January is Cervical Health Awareness month, a time to spread the word about steps women can take to prevent and detect cervical cancer.
The good news? Cervical cancer is largely preventable and, if detected early, curable. The key to prevention is vaccination and the key to early detection comes down to two tests. The Food and Drug Administration (FDA) is responsible for evaluating the safety and effectiveness of these measures and determining whether to approve them before they can be used in the U.S.
Cervical cancer is cancer that forms in the cervix, the lower, narrow part of the uterus that connects with the vagina. It is caused by the human papillomavirus (HPV). In the U.S. in 2013, there were approximately 12,000 new cases of cervical cancer and 4,000 deaths, according to estimates by the National Cancer Institute.
The two tests for cervical cancer are the Pap test (or Pap smear) and the HPV test. According to Shyam Kalavar, a cytologist (an expert in the microscopic examination of cells) at FDA, the Pap smear looks at cells obtained from the cervix for abnormalities that may become cervical cancer if not treated appropriately.
When a Pap smear shows abnormalities, further testing or follow-up is needed. Follow-up testing may include an HPV test to check for the presence of the types of HPV most likely to cause cancer and/or a biopsy of the cervix. There are more than 100 different kinds of HPV, and not all of them cause health problems.
"If cervical cancer is found early, it's easier to treat," Kalavar says. Because this form of cancer often causes no pain, a woman can have cervical cancer and not know it, making the importance of testing that much greater.
The Pap smear is not 100% accurate, and cervical cancer may be missed in a small number of cases. However, it usually takes years, if not decades, for abnormal cells to develop into cervical cancer. Regular Pap smears—as recommended in the 2012 guidelines from the American Cancer Society, the American Society for Coloposcopy and Cervical Pathology (ASCCP), and the American Society for Clinical Pathology—should identify changes in time for treatment.
In the original Pap smear method (known as the conventional method) cells scraped from the opening of the cervix are placed onto a glass slide and examined under a microscope, explains Kalavar. In the past 15 to 20 years, however, automated, liquid-based Pap testing, in which the sample is placed in a liquid before the cells are deposited on a glass slide and examined under a microscope, has largely replaced the original test. Currently, there are two FDA-approved liquid-based tests on the market.
Regardless of what type of Pap test is used, a woman can also be tested for the presence of high-risk types of HPV, a process known as "Pap and HPV co-testing." Co-testing is less likely to miss an abnormality than Pap testing alone. Women may want to talk to their healthcare professionals about this option.
FDA has approved three vaccines to prevent cervical cancer: Gardasil, Gardasil 9, and Cervarix. "These vaccines are preventative and work like other vaccines that prevent diseases caused by viruses and bacteria: they prompt the body to produce antibodies (disease-fighting substances) to protect against infection," says Marion Gruber, Ph.D., director of FDA's Office of Vaccines Research and Review.
FDA has determined that all three vaccines are effective in preventing cervical cancer caused by the two types of high-risk HPVs that cause about 70 percent of cervical cancers. In addition, Gardasil 9 adds protection against five additional HPV types which cause approximately 20 percent of cervical cancers and are not covered by previously FDA-approved HPV vaccines.
For all of the vaccines, the full potential for benefit is obtained by those who are vaccinated prior to becoming infected with the HPV strains covered by the vaccine. None of the vaccines will protect against the types of HPV that are not covered by the vaccine, Gruber says. She adds that the vaccines cannot be used to treat (rather than prevent) HPV infections or cervical cancer.
FDA has approved Gardasil and Gardasil 9 for use in females ages 9 through 26 for the prevention of cervical as well as vulvar, vaginal and anal cancers, as well as genital warts. It is also approved for the prevention of genital warts and anal cancer in males ages 9 through 26. Cervarix is approved for use in females ages 9 through 25 for the prevention of cervical cancer.
"Women, including those who have been vaccinated, should continue to get Pap tests because they are essential to detect cervical cancer and precancerous changes," Gruber notes.
This article appears on FDA's Consumer Updates page, which features the latest on all FDA-regulated products.
Updated January 21, 2016