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US Public Health Service. Office of Disease Prevention and Health Promotion. Clinician's Handbook of Preventive Services. 2nd edition. Washington (DC): Department of Health and Human Services (US); 1999.

  • This publication is provided for historical reference only and the information may be out of date.

This publication is provided for historical reference only and the information may be out of date.

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Clinician's Handbook of Preventive Services. 2nd edition.

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37Papanicolaou Smear

In 1997 approximately 14,500 cases of invasive cervical cancer are expected to be diagnosed in the United States and 4800 women are expected to die of the disease. The major risk factor for cervical cancer is sexually transmitted infection with human papillomavirus (HPV). Other risk factors include early age at first intercourse, having multiple sexual partners, long-term use ( > 5 years) of oral contraceptives, low socioeconomic status, and cigarette smoking. Rates for carcinoma in situ reach a peak in both African-American and white women between the ages of 20 and 30 years. After age 25 years, the incidence of invasive cancer in African-American women increases dramatically with advancing age. In Caucasian women, the incidence rises more slowly. Over 25% of invasive cervical cancers occur in women older than age 65 years, and 40% to 50% of all women who die of cervical cancer are older than age 65 years.

The effectiveness of early detection through Papanicolaou (Pap) smear testing and early treatment has been impressive, resulting in a marked decrease in mortality from cervical cancer. The incidence of invasive cervical cancer has decreased an estimated 70% because of screening. Nonetheless, a large proportion of women, particularly elderly African-American women and middle-aged women of lower socio-economic status, do not have regular Pap smears. In some geographic areas, as many as 75% of women over age 65 years report not having a Pap smear within the previous 5 years.

Depending on the technique used, Pap testing has a sensitivity of 50% to 90% and a specificity of 90% to 99%. A large proportion of false-negative Pap smear results are thought to be attributable to inadequate collection technique (up to 50% of all false-negative results) and inadequate laboratory interpretation. Because of the long lead time from development of precancerous changes until development of invasive carcinoma (8 to 9 years by some estimates), almost all precancerous or early-stage malignancies initially missed can be detected by repeat testing.

Recommendations of Major Authorities

  • American Academy of Family Physicians --
  • All women who are or have been sexually active and who have a cervix should be offered a Pap smear at least every 3 years. Use of Pap smears is not recommended in women who have had hysterectomies for reasons other than cancer.
  • American Cancer Society and American College of Obstetricians and Gynecologists, and National Cancer Institute --
  • All women should begin having annual Pap tests at the onset of sexual activity or at 18 years of age, whichever occurs first. After a woman has had three or more consecutive satisfactory normal annual examinations, the Pap test may be performed less frequently in low-risk women at the discretion of the patient and clinician.
  • American College of Physicians --
  • Sexually active women between 20 and 65 years of age should be screened with a Pap smear every 3 years. Women 66 to 75 years of age who have not been screened within the 10 years prior to age 66 should be screened every 3 years. Women at increased risk for cervical cancer should be screened every 2 years. Initial screening tests may be done as frequently as annually for two or three examinations to ensure diagnostic accuracy.
  • American College of Preventive Medicine --
  • Screening for cervical cancer by regular Pap tests should be performed in all women who are or have been sexually active, and should be instituted after a woman first engages in sexual intercourse. If the sexual history is unknown or considered unreliable, screening should begin at age 18. At least two initial screening tests should be performed one year apart. For women who have had at least two normal annual smears, the screening interval may be lengthened at the discretion of the patient and physician but should not exceed three years. Screening may be discontinued at age 65 if the following criteria are met: the women has been regularly screened, has had two satisfactory smears, and has had no abnormal smears within the previous nine years. For all women over age 65 who have not been previously screened, three normal annual smears should be documented prior to discontinuation of screening.
  • Canadian Task Force on the Periodic Health Examination --
  • Pap smears to screen for cervical cancer are recommended for women who have been sexually active. The optimum frequency of screening is not known, but it is suggested that women in the general population be screened annually until two normal smears are reported and then every 3 years to age 69 years. More frequent screening should be considered for women with risk factors: age of first sexual intercourse less than 18 years, many sexual partners or a consort with many partners, smoking, or low socioeconomic status.
  • US Preventive Services Task Force --
  • All women who are or have been sexually active should have regular Pap tests. Testing should begin at the age when the woman first engages in sexual intercourse. Adolescents whose sexual history is thought to be unreliable should be presumed to be sexually active at age 18. There is little evidence that annual screening achieves better outcomes than screening every 3 years. Pap tests should be performed at least every 3 years. The interval for each patient should be recommended by the physician based on risk factors (eg, early onset of sexual intercourse, history of multiple sexual partners, low socioeconomic status). Women infected with human immunodeficiency virus require more frequent screening according to established guidelines. There is insufficient evidence to recommend for or against an upper age limit for Pap testing, but recommendations can be made on other grounds to discontinue regular testing after 65 years of age in women who have had regular previous screening with consistently normal results. Women who have undergone a hysterectomy in which the cervix was removed do not require Pap testing, unless the hysterectomy was performed because of cervical cancer or its precursors.

Basics of Pap Smear Screening

1. Attempt to ensure that performance of a Pap smear is not an unpleasant or painful experience for the patient. Be sure to clearly explain the importance of the procedure and the steps used to carry it out.

2. Instruct patients not to douche on the day of the examination. Do not perform a Pap smear if the patient has significant menstrual flow or obvious inflammation.

3. Perform the Pap smear before performing the bimanual examination and before obtaining culture specimens. In general, do not lubricate the speculum with anything except water, because contamination of Pap smear specimens with lubrication jelly tends to obscure cellular detail. Use of a small amount of lubricating jelly may be necessary for speculum insertion in some older patients.

4. Visualize the cervix and vagina completely before collecting the specimen. Gently remove any excess cervical mucus with a swab.

5. The traditional gold standard for the adequacy of a Pap smear has been the presence of endocervical cells in the sample: 90% of cervical cancers develop at the junction of the squamous epithelium of the ectocervix and the columnar epithelium of the endocervix (located at the external os in young women and inside the endocervical canal in older women). Studies differ regarding whether the presence of endocervical cells actually improves detection rates of abnormalities, but the presence of endocervical cells and/or squamous metaplastic cells remain widely accepted as a standard of adequacy for Pap smears.

6. A variety of implements have been used to obtain Pap smear samples, including simple cotton swabs, wooden and plastic spatulas, and endocervical and combined endocervical-exocervical brushes. The best sensitivity (defined as presence of endocervical cells) is achieved by using both a spatula (preferably Ayer's type) and an endocervical brush. Use the spatula first, because bleeding is commonly caused by the endocervical brush, and endocervical cells are susceptible to drying effects.

7. Gently yet firmly rotate the spatula around the os at least one complete turn to obtain a 360 ° sample. Promptly transfer the specimen to a glass slide (or to a preservative vial if your laboratory is using a thin layer technique). Patients who have been exposed to DES should also have smears taken circumferentially with a spatula from the upper two thirds of the vagina. To obtain the endocervical sample, insert the brush into the os no deeper than the length of the bristled section. Rotate the brush 360 ° (avoiding excessive rotation), then transfer the specimen by rolling the brush on a glass slide or by placing the material in a preservative vial as instructed by your laboratory for the thin layer technique.

8. Apply specimens to the slides uniformly and without clumping. Perform fixation promptly, and take care to minimize air drying of the specimens. If one slide is used for both specimens, collect, transfer, and fix the endocervical sample as quickly as possible. Use of two separate slides can help avoid prolonged air exposure of the spatula specimen while the endocervical specimen is being collected. Use of two slides does, however, double the amount of work for the cytotechnologist. Use of a combined endocervical-exocervical brush requires collection and fixation of only a single specimen (thus decreasing the risk of air drying), but such use has been shown to be somewhat less sensitive than use of a spatula and an endocervical brush.

9. Inquire about the quality control procedures of the laboratories to which specimens are sent. Laboratories should be certified by the American Society of Cytopathology, the College of American Pathologists, the Health Care Financing Administration, the Joint Commission on the Accreditation of Health Care Organizations, or the New York State Department of Health.

10. Many authorities recommend that laboratories use the new Bethesda System developed by a National Cancer Institute consensus conference for reporting results (Table 37.1). The Bethesda System attempts to standardize classification categories and provides for reporting on aspects of the sample not addressed in traditional Pap smear reports, such as adequacy of the sample submitted. In the Bethesda System, HPV infection is classified as a low-grade squamous intraepithelial lesion. Both moderate and severe dysplasia are classified as high-grade squamous intraepithelial lesions. Some concern exists, although unsubstantiated by research, that these classifications may lead to excessive use of colposcopic examination for patients with HPV infection or moderate dysplasia. The American College of Obstetricians and Gynecologists has issued guidelines for Pap smear reporting and follow-up in their publication Cervical Cytology: Evaluation and Management of Abnormalities (Selected References).

Table 37.1.The Revised Bethesda System for Reporting Cervical and/or Vaginal Cytologic Diagnoses.


Table 37.1.The Revised Bethesda System for Reporting Cervical and/or Vaginal Cytologic Diagnoses.

11. General recommendations for initial follow-up of abnormal PAP smears according to the American College of Obstetricians and Gynecologists include:

ASCUS (Atypical Squamous Cells of Undetermined Significance): The prognosis of women with ASCUS varies depending on the cytopathologist or laboratory. Clinicians are encouraged to communicate with the cytopathologist or to monitor a number of patients with an ASCUS report to help determine the appropriate follow-up and the need for colposcopy.

LSIL (Low-grade Squamous Intraepithelial Lesions): Repeat Pap test at intervals of 4 to 6 months and colposcopy if abnormalities persist.

High-grade Squamous Intraepithelial Lesions: Colposcopy and directed biopsy.

12. Only about 60% of women with abnormal Pap smear results return for follow-up. Establish a tracking system to make sure that Pap smears are performed regularly, that results return in a timely fashion, that patients with abnormal results are contacted, and that women who are not seen frequently are called or contacted by letter about the importance of getting Pap smears and other needed preventive care. Encourage patients to keep track of the results and prompt their own Pap smears through use of a patient-held record form or card.

Patient Resources

  • The Pap Test. American College of Obstetricians and Gynecologists, 409 12th St, SW, Washington DC 20024; (800)762-2264. Internet address:
  • The Pap Test: It Could Save Your Life. To order this information (in Spanish), contact the Office of Cancer Communications, National Cancer Institute, Bldg 31, Room 10A16, Bethesda, MD 20892; 1-800-4-CANCER.

Provider Resources

  • Cervical Cytology: Evaluation and Management of Abnormalities. Technical Bulletin 183. American College of Obstetricians and Gynecologists, 409 12th St, SW, Washington, DC 20024; 1-800-762-2264. Internet address:
  • Recommended Actions to Assure Quality Pap Tests (Pap Smears). The American Society of Clinical Pathologists. American Society of Clinical Pathologists, 1225 New York Ave, NW, Suite 250, Washington, DC 20005; 202-347-4450. Internet address:
  • PDQ: The Physician Data Query System for Cancer Information. PDQ is the National Cancer Institute's computerized database providing the most up-to-date cancer information available. Access to the system can be gained 24 hours a day, 7 days a week, using a personal computer and a standard telephone line or through medical libraries. Ask a medical librarian for assistance or call (800)4-CANCER (line 3). In Hawaii, on Oahu, call 524-1234.

Selected References

  1. American Academy of Family Physicians. Summary of Policy Recommendations for Periodic Health Examination . Kansas City, Mo: American Academy of Family Physicians; 1997.
  2. American Cancer Society. Cancer Facts and Figures — 1997. Atlanta, Ga: American Cancer Society; 1997.
  3. American Cancer Society. Summary of American Cancer Society recommendations for the early detection of cancer in asymptomatic people. CA . 1993; 43:–.
  4. American College of Obstetricians and Gynecologists. Guidelines for Women's Health Care. Washington, DC: American College of Obstetricians and Gynecologists; 1996.
  5. American College of Physicians. Guidelines. In: Eddy DM, ed. Common Screening Tests. Philadelphia, Pa: American College of Physicians; 1991:413-414.
  6. Appleby J. Management of the abnormal Papanicolaou smear. Med Clin North Am . 1995; 79:345–360. [PubMed: 7877395]
  7. Boon ME, de Graaff Guilloud JC, Rietveld WJ. Analysis of five sampling methods for the preparation of cervical smears. Acta Cytol . 1989; 33:843–848. [PubMed: 2588917]
  8. Canadian Task Force on the Periodic Health Examination. Screening for cervical cancer. In: The Canadian Guide to Clinical Preventive Health Care. Ottawa, Canada: Minister of Supply and Services; 1994: chap 73.
  9. Crouse BS, Elliott BA, Nesin N. Clinical follow-up of cervical sampling with the Ayre spatula and Zelsmyr cytobrush. Arch Fam Med. 1993;2:145-148.
  10. Eddy DM. Screening for cervical cancer. In: Eddy DM, ed. Common Screening Tests. Philadelphia, Pa: American College of Physicians; 1991: chap 10.
  11. Hawkes AP, Kronenberger CB, MacKenzie TD, et al. Cervical cancer screening: American College of Preventive Medicine practice policy statement. Am J Prev Med. . 1996; 12(5):342–344. [PubMed: 8909644]
  12. Herbst AL. The Bethesda System for cervical/vaginal cytologic diagnoses: a note of caution. Obstet Gynecol. 1990;449-450.
  13. Kruman RJ, Solomon D. The Bethesda System for Reporting Cervical/Vaginal Cytologic Diagnoses. Definitions, Criteria, and Explanatory Notes for Terminology and Specimen Adequacy. New York, NY: Springer-Verlag; 1994.
  14. Lai-Goldman M, Nieberg RK, Mulcahy D, Wiesmeier. The cytobrush for evaluating routine cervicovaginal-endocervical smears. J Repro Med . 1990; 35:959–963. [PubMed: 2246763]
  15. McCord ML, Stovall TG, Meric JL, Summitt RL, Coleman SA. Cervical cytology: a randomized comparison of four sampling methods. Am J Obstet Gynecol . 1992; 166:1772–1779. [PubMed: 1615986]
  16. Mandelblatt J, Gopaul I, Wistreich M. Gynecological care of elderly women: another look at Papanicolaou testing. JAMA . 1986; 256:367–371. [PubMed: 3723723]
  17. Miller AB, Anderson G, Brisson J, et al. Report of a national workshop on screening for cancer of the cervix. Can Med Assoc J . 1991; 145:1301–1325. [PMC free article: PMC1335946] [PubMed: 1933712]
  18. National Cancer Institute Workshop. The 1988 Bethesda System for reporting cervical/vaginal cytologic diagnoses. JAMA . 1989; 262:931–934. [PMC free article: PMC1133362] [PubMed: 2754794]
  19. National Cancer Institute Workshop. The revised Bethesda System for reporting cervical/vaginal cytologic diagnoses: report of the 1991 Bethesda workshop. Acta Cytol . 1992; 36:273–275. [PMC free article: PMC188349] [PubMed: 1580108]
  20. Neinstein JS, Church J, Akiyoshi T. Comparison of cytobrush with cervix-brush for endocervical cytologic sampling. J Adoles Health . 1992; 13:520–523. [PubMed: 1390820]
  21. Ruffin MT, Van Noord GR. Improving the yield of endocervical elements in a Pap smear with the use of the cytology brush. Fam Med . 1991; 23:365–369. [PubMed: 1884932]
  22. Schumann JL, O'Connor DM, Covell JL, Greening SE. Pap smear collection devices: technical, clinical, diagnostic, and legal considerations associated with their use. Diagn Cytopathol. 1992;8:492-502.
  23. US Preventive Services Task Force. Screening for cervical cancer.In: Guide to Clinical Preventive Services. 2nd ed. Washington, DC: US Department of Health and Human Services; 1996: chap 9.


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