Putting Evidence into Practice: An Evidence-Based Approach
Screening for Cervical Cancer
Am Fam Physician. 2003 Aug 1;68(3):525-526.
TS, a 24-year-old, sexually active, white woman, visits your office to discuss birth control methods. She first had intercourse at age 16 and smokes two packs of cigarettes per week. You suggest that she be screened for cervical cancer as part of routine health maintenance. She asks how you will perform the screening and how often she should be screened.
Case Study Questions
1. Which one of the following statements regarding the U.S. Preventive Services Task Force (USPSTF) recommendations on screening for cervical cancer is correct?
A. The USPSTF strongly recommends screening women who have been sexually active and have a cervix.
B. The USPSTF strongly recommends screening women aged 25 and older.
C. The USPSTF does not recommend for or against screening women for cervical cancer.
D. The USPSTF recommends screening only women who are at increased risk for cervical cancer.
E. The USPSTF recommends screening all women between the ages of 18 and 75.
2. Which one of the following tests is recommended by the USPSTF for routine cervical cancer screening?
A. Human papillomavirus (HPV) testing.
B. Liquid-based cytology.
C. Conventional Papanicolaou (Pap) smear screening.
D. Computerized rescreening.
E. Conventional Pap smear screening and HPV testing.
3. Which of the following is/are risk factors for developing cervical cancer?
A. Cigarette smoking.
B. Infection with certain strains of HPV.
D. Early onset of sexual intercourse.
1. The correct answer is A. The USPSTF strongly recommends cervical cancer screening for women who have been sexually active and have a cervix. Direct evidence to determine the optimal starting age, stopping age, and screening interval is limited. However, indirect evidence suggests that most of the benefit can be obtained by initiating screening within three years of the onset of sexual activity or age 21 (whichever comes first) and by screening at least every three years. The USPSTF recommends against routinely screening women older than 65 for cervical cancer if they have had adequate recent screening with normal Pap smear results and are not otherwise at high risk for cervical cancer. The risk of cervical cancer and the yield of screening declines in older women, and there is fair evidence that screening women older than 65 is associated with increased rates of false-positives and risk of potential harms. For women who have had a total hysterectomy for benign disease, the USPSTF recommends against cervical cancer screening.
2. The correct answer is C. The USPSTF found good evidence that screening with cervical cytology (i.e., Pap smears) reduces incidence of and mortality from cervical cancer. The USPSTF found poor evidence to determine whether new technologies, such as liquid-based cytology, computerized rescreening, and algorithm-based screening, are more effective than conventional Pap smear screening. No study has assessed health outcomes resulting from screening with new technologies compared with conventional Pap screening. The USPSTF also found poor evidence to determine the benefits and potential harms of HPV screening as an adjunct or alternative to conventional Pap smear screening. However, trials that should clarify the role of HPV testing are underway. It may eventually have a role in primary screening if it can reliably distinguish between women who would benefit from more intensive screening and women for whom screening could be less intensive or even discontinued.
3. The correct answers are A, B, C, and D. Cigarette smoking is strongly correlated with cervical dysplasia and cancer, independently increasing risk by up to fourfold. Infection with high-risk strains of HPV, however, is the most important risk factor for cervical cancer. HPV is a necessary but insufficient precursor of cervical cancer. Factors such as age, nutritional status, immune function, and possibly silent genetic polymorphisms modulate the incorporation of viral DNA into host cells. Sexual behaviors associated with an increased cervical cancer risk include early onset of intercourse and a greater number of lifetime sexual partners.
Hartman KE, Hall SA, Nanda K, Boggess JF, Zolnoun D. Screening for cervical cancer. Systematic Evidence Review No. 25. (Prepared by the Research Triangle Institute-University of North Carolina Evidence-based Practice Center under contract No. 290-97-0011). Rockville, Md.: Agency for Healthcare Research and Quality, 2002.
U.S. Preventive Services Task Force. Screening for cervical cancer. Recommendations and rationale. AHRQ Publication No. 03-515A. Rockville, Md.: Agency for Healthcare Research and Quality, 2003.
The case study and answers to the following questions on screening for cervical cancer are based on the recommendations of the current U.S. Preventive Services Task Force (USPSTF), part of the Put Prevention into Practice program of the Agency for Healthcare Research and Quality (AHRQ). This recommendation was released in 2002 and is an update of the 1996 recommendation on screening for cervical cancer. More detailed information on this subject is available in the Systematic Evidence Review and USPSTF Recommendations and Rationale on the AHRQ Web site (www.ahrq.gov). The recommendation statement is also available from the AHRQ Publications Clearinghouse in print through subscription to the Guide to Clinical Preventive Services, Third Edition: Periodic Updates. To order, contact the Clearinghouse at 1-800-358-9295 or e-mail firstname.lastname@example.org.
Copyright © 2003 by the American Academy of Family Physicians.
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