Annual breast cancer screening for women aged >50 years is widely recommended. In addition, screening is recommended for women aged 40-49 years; however, consensus has not been reached regarding the effectiveness of screening or the optimal interval for screening in this age group (20). Several review groups have reached different conclusions about the efficacy of mammography among younger women because of the limitations of studies conducted among women in this age group. These limitations include small sample sizes and limited duration of follow-up after entry into the screening programs (21).

In 1996, the U.S. Preventive Services Task Force (USPSTF) recommended that women aged 50-69 years receive routine breast cancer screening every 1-2 years using mammography alone or mammography combined with annual CBE (14). USPSTF noted that insufficient evidence exists to recommend or not recommend routine mammography or CBE for women aged 40-49 years and >70 years. Moreover, insufficient evidence exists to recommend CBE alone or teaching breast self-examination. In addition, USPSTF noted that recommendations for mammography among high-risk women aged 40-49 years and among healthy women aged >70 years might be made on other grounds.

In 1997, a National Institutes of Health Consensus Development Conference panel reviewed new data not previously available to USPSTF, which documented mortality benefit from mammography among women aged 40-49 years (22). However, the panel concluded that these data did not warrant a universal recommendation for mammography for women aged 40-49 years. As a result, the panel encourages these women to determine for themselves whether to receive mammography on the basis of objective analysis of scientific evidence, individual health history, and perceived risks and benefits (20).

Because mortality can be reduced among women aged 40-49 years, in 1997 the National Cancer Institute (NCI) accepted new guidelines for mammography screening recommended by the presidentially appointed National Cancer Advisory Board. These guidelines recommend that all women aged >40 years receive mammography every 1-2 years to achieve the best possible outcome if breast cancer is detected (22).

Prevalence of Breast Cancer Screening

Data collected through CDC's 1997 Behavioral Risk Factor Surveillance System (BRFSS) indicate that 85% of all interviewed women aged >40 years had ever received a mammogram (23). The percentage of low-income women and women without health insurance who had ever received a mammogram was comparable (77% and 69%, respectively). The percentage of all interviewed women aged >40 years who had received a mammogram within the preceding 2 years was 71%. Rates for low-income women and women without health insurance were substantially lower (58% and 50%, respectively).

A Healthy People 2000 objective is to increase to at least 80% the proportion of women aged >40 years who have ever received a CBE and a mammogram, and to at least 60% those aged >50 years who have received them within the preceding 1-2 years (objective 16.11) (24). Although 1997 BRFSS data indicate the goal has been attained for all women interviewed aged >40 years who had ever received a mammogram, progress is still needed to attain the goal for low-income women and women without health insurance. 

Cervical Cancer

Effective control of cervical cancer depends primarily on early detection of precancerous lesions through use of the Pap test, followed by timely evaluation and treatment. The Pap test is probably the most successful screening test ever developed to detect a cancer. Although the efficacy of cervical cancer screening using the Pap test has not been evaluated in clinical trials, at least two factors support the positive impact of this screening test: a) evidence from many observational studies and b) the marked decline in cervical cancer incidence and death rates in the United States and other countries since the introduction of the Pap test >40 years ago (14,25).

In the United States, approximately 50 million Pap tests are performed annually (26). Approximately 10% of these tests indicate an abnormality requiring further testing. Detection and treatment of precancerous cervical intraepithelial neoplasia (CIN) lesions identified by the Pap test can prevent cervical cancer. Thus, the intended outcome of cervical cancer screening differs from breast cancer screening. The primary goal of cervical cancer screening is to detect and treat CIN to prevent the occurrence of invasive cancer. For women in whom CIN lesions have been detected, the likelihood of survival is nearly 100% with appropriate evaluation, treatment, and follow-up.

Cervical Cancer Screening Guidelines Recommended by Various Groups

The American College of Obstetricians and Gynecologists (ACOG) and ACS recommend that women have a Pap test and pelvic examination when they become sexually active or at age 18 years, whichever occurs first (13). Annual Pap tests are recommended until three consecutive Pap tests are interpreted as being normal. Following this, the two groups recommend that Pap tests can be performed less frequently at the discretion of the provider (13).

In 1996, USPSTF recommended routine screening for women who are or who have been sexually active and who have a uterine cervix (14). The task force recommends Pap tests with the onset of sexual activity and repeated screening every 3 years. A reduced interval between screenings can be recommended by the physician on the basis of a woman's risk factors for cervical cancer. In addition, USPSTF recommends that, on the basis of existing evidence, Pap screening might not be necessary for women after age 65 years. Moreover, USPSTF recommended not performing Pap tests on women who have undergone total hysterectomies for diseases unrelated to cervical cancer or its precursors (14).

In recent years, several studies have been conducted to determine the value of expanding HPV testing from testing only women with abnormal Pap test results to routinely testing all women to detect those women at greatest risk for developing CIN or invasive cervical cancer. Evidence from these studies does not support routine HPV testing to screen for cervical cancer (26). Although new cervical cancer screening technologies have been approved for primary screening, professional organizations have not endorsed their widespread use because of concerns about cost effectiveness.

An increasing concern is that rescreening the same women annually will not result in further reductions in cervical cancer mortality (27). Increased effort is needed to target groups with large proportions of unscreened or rarely screened women, including women residing in rural areas; minorities; and recent immigrants who have different attitudes, knowledge, and behaviors regarding disease prevention and health promotion. Screening for cervical cancer among these women could further reduce the burden of disease from cervical cancer.

Prevalence of Cervical Cancer Screening

The 1997 BRFSS documented that 93% of women aged >18 years with a uterine cervix reported ever having received a Pap test (23). Corresponding values for low-income and uninsured women were 89% and 85%, respectively. Among all women with a uterine cervix, 80% had obtained a Pap test within the preceding 2 years. For low-income women and uninsured women, the proportion who had obtained a Pap test was substantially lower (69% and 65%, respectively).

A Healthy People 2000 objective is to increase to at least 95% the proportion of women aged >18 years with a uterine cervix who have ever received a Pap test, and to at least 85% those who have received a Pap test within the preceding 1-3 years (objective 16.12) (24). Although 1997 BRFSS data indicate the goal for women aged >18 years with a uterine cervix who reported ever having received a Pap test is near attainment, progress is still needed, as with breast cancer screening, to attain the goal for low-income women and women without health insurance.

Low income and lack of health insurance are barriers to both cervical and breast cancer screening. These factors increase the likelihood that these diseases will be diagnosed at a later stage, when survival rates are lower (1). 

Implementation of the National Breast and Cervical Cancer Early Detection Program

In August 1990, Congress enacted the Breast and Cervical Cancer Mortality Prevention Act, thereby authorizing CDC to establish a national public health infrastructure to increase breast and cervical cancer screening among low-income women who are uninsured (28). Consequently, CDC established the National Breast and Cervical Cancer Early Detection Program (NBCCEDP), a comprehensive women's health initiative implemented through cooperative agreements with qualifying health agencies (including state and territorial health departments and American Indian/Alaska Native tribes and tribal organizations). In addition to providing breast and cervical cancer screening, participating programs provide diagnostic testing, surveillance and follow-up, case management, public education and outreach, professional education and training, quality assurance of screening tests, coalition and partnership development, and program evaluation. NBCCEDP-sponsored programs have initiated outreach efforts to serve women in high priority groups (e.g., women with increased risk for breast or cervical cancer and women who do not or rarely access breast and cervical cancer screening), including older women, racial/ethnic minorities, foreign-born women, women with disabilities, lesbians, and women residing in rural or other hard-to-reach areas.

Fiscal year (FY) 2000 marked the 10th year of the NBCCEDP, with Congressional appropriations of $167 million. CDC provides funds to all 50 states, six U.S. territories, the District of Columbia, and 15 American Indian/Alaska Native tribes and tribal organizations to implement comprehensive screening programs for breast and cervical cancer (29).

During the reporting period July 1991-March 1999, approximately 2.2 million screenings for breast and cervical cancer were provided to uninsured women. The program supported 1,049,752 mammograms: 64% of the mammograms were provided to women aged >50 years; 48% were provided to racial/ethnic minorities (Figure 3). Breast cancer was diagnosed in 6,265 women aged >40 years. Although the rate of abnormalities detected by a mammogram was highest for younger women, the rate of breast cancers detected per 100,000 mammograms increased directly with advancing age (Figure 4). A total of 1,192,346 Pap tests were performed: 72% of the tests were provided to women aged >40 years; 47% were provided to racial/ethnic minorities (Figure 5). Cervical intraepithelial neoplasia was detected in 34,046 women. Invasive cervical cancer was diagnosed in 561 women. The rate of abnormal Pap tests varied inversely with age.

Policy of NBCCEDP

As NBCCEDP has evolved, the program has addressed many challenges, especially regarding screening recommendations and treatment resources for women in whom precancerous cervical lesions or cancer of the breast or cervix has been diagnosed through NBCCEDP. FY 2000 Congressional appropriations will enable NBCCEDP to screen approximately 12%-15% of the eligible uninsured women aged 50-64 years in the United States (30). The remaining unmet need and the absence of funding to cover treatment expenses for women who have received a diagnosis of precancerous cervical lesions or breast or cervical cancer have been persistent challenges to the program. A key public health priority of NBCCEDP is to direct program resources to eligible women who have rarely or have never received breast or cervical cancer screening. To address this priority and maximize efficient use of limited resources, the program has developed cancer-control policies on the basis of programmatic data, current scientific research, and availability of screening services through other government-supported programs (e.g., Medicare and Title X Family Planning programs).

Breast Cancer Screening Policies

Following implementation of NBCCEDP in 1991, CDC encouraged NBCCEDP- sponsored programs to place a high priority on screening women aged >50 years. NBCCEDP data indicated that only 57% of their mammograms were provided to women aged >50 years. In October 1994, CDC established the first age-specific targets for the breast cancer screening component of NBCCEDP. For 1995, 75% of the mammograms were to be provided to women aged >50 years. The percentage was gradually increased to 90% by October 1998. A review of NBCCEDP mammography screening data in 12-month intervals indicated that, since 1994, programs had screened increasing numbers of women aged >50 years for breast cancer; however, the age-specific percentage goals had not been attained. For example, the percentage of initial mammograms provided to women aged >50 years for the reporting period October 1996-September 1997 was 74%.

In 1998, NBCCEDP mammogram screening policy was revised in response to new scientific research, recent changes in recommendations by NCI and ACS, changes in Medicare preventive services coverage, and the need to establish a more realistic national target based on historical programmatic screening data. The new NBCCEDP policy is to provide at least 75% of mammograms to women aged >50 years who are not eligible to receive Medicare Part B benefits or are unable to pay the premium to enroll in Medicare Part B. Correspondingly, no more than 25% of mammograms should be provided to women aged <50 years. As a result of this new policy, some participating health agencies have developed strategies to cover breast cancer screening for women aged 40-49 years. Several programs have obtained breast cancer screening resources for these women from state appropriations or tobacco tax revenues and through collaborative efforts with foundations (e.g., the Susan G. Komen Breast Cancer Foundation). During October 1997-September 1998, 75% of NBCCEDP-sponsored mammograms were provided to women aged >50 years.

Cervical Cancer Screening Policies

The primary purpose of the cervical cancer component of NBCCEDP is to identify and treat precancerous cervical lesions and to detect and treat invasive cervical cancer at an early stage. When the program was established in 1991, CDC implemented program guidelines for cervical cancer screening that were consistent with ACS guidelines. Women enrolled in NBCCEDP who were aged >18 years, with an intact uterine cervix, were eligible for an annual Pap test and pelvic examination. After a woman has had three consecutive annual examinations with normal findings, Pap tests could be performed less frequently at the discretion of the woman and her health-care provider.

In 1999, CDC, in consultation with an external work group comprising clinical experts, epidemiologists, and public health practitioners, reexamined NBCCEDP's cervical cancer screening policy and other emerging issues related to Pap testing. One of the key issues addressed by this work group was recommendations for Pap screening intervals.

ACOG's and ACS's recommendations regarding the frequency of screening are similar and advise that after a woman has had three consecutive annual examinations with normal findings, the Pap test can be performed less frequently at the discretion of the woman's provider. Scientific data suggest that once a woman has demonstrated no signs of CIN, as evidenced by three consecutive annual Pap tests with normal findings, her chance of developing CIN II or worse within a 3-year period is extremely low, regardless of other risk factors (31). Preliminary analysis of NBCCEDP data supports these findings (CDC, unpublished data, 2000).

Beginning in March 2000, NBCCEDP-sponsored programs will be required to direct more cervical cancer screening resources to women who have never had a Pap test or who have not had a Pap test for at least 5 years. Among all women screened, at least 20% should be women who have either never been screened or have rarely been screened (i.e., not screened for >5 years). Programs are also being required to reduce over-screening among program-enrolled women. Beginning in October 2001, programs will be required to document that at least 75% of women with three consecutive annual Pap tests with normal findings did not receive a fourth annual Pap test. Their screening interval will be changed to every 3 years. To successfully implement this policy change, CDC will assist NBCCEDP-sponsored programs in assessing current program provider practices, modifying patient recall systems, and developing professional and public education strategies.

Breast and Cervical Cancer Follow-Up and Treatment Policy

The policy issue that has caused the greatest controversy in NBCCEDP concerns the availability of funds to pay for treatment of cancerous or precancerous lesions diagnosed in enrolled women (28). A crucial component of NBCCEDP is to ensure that all women with abnormal screening results, precancerous breast or cervical lesions, or a diagnosis of cancer receive timely and appropriate follow-up care. Program providers receive reimbursement for most diagnostic procedures, including diagnostic mammography, breast ultrasound, fine-needle aspiration of the breast, breast and cervical biopsies, and colposcopy of the cervix. However, the Breast and Cervical Cancer Mortality Prevention Act of 1990 prohibits use of federal program funds for any component of breast or cervical cancer treatment primarily because of a concern that such payment would rapidly deplete resources available for screening services. NBCCEDP-sponsored programs are required to identify and secure resources for treatment from other sources.

In 1996, CDC conducted in-depth case studies of seven state programs to determine how early detection programs identified and obtained resources for treatment. The results indicated that state health agencies and their partners had developed a wide range of strategies for procuring treatment services in the absence of program resources. However, the study respondents considered the strategies used to obtain these services as short-term solutions that were labor intensive and that diverted resources away from screening activities (32).

NBCCEDP surveillance data for October 1991September 1998 indicate that 92% of the clients in whom breast cancer had been diagnosed and 93% of the clients in whom invasive cervical cancer had been diagnosed initiated treatment. The remainder either refused treatment, were lost to follow-up, or had an outcome pending. In FY 1999, CDC received increased Congressional appropriations to expand case-management activities to assist women in overcoming financial, logistical, and other barriers to obtaining these services.

Recommended Priority Activities for CDC

The Breast and Cervical Cancer Mortality Prevention Act of 1990 has played an important role in focusing public health efforts on cancer control in the United States. Since 1991, CDC has collaborated with a diverse group of public and private partners to build the public health infrastructure, implement screening services, and conduct research activities. CDC will continue to foster these relationships to achieve goals set in the following four priority areas of screening initiatives, case-management services, professional education and training, and partnerships:

Screening Initiatives

• Collaborate with NBCCEDP-sponsored programs to increase public education and outreach strategies to reach women who have rarely or have never received breast or cervical cancer screening.
• Collaborate with NBCCEDP-sponsored programs to implement strategies among health-care providers to address missed opportunities for enrolling women into screening.
• Collaborate with NBCCEDP-sponsored programs to implement strategies through professional groups and public education to modify screening intervals for all program-enrolled women who have had three consecutive annual Pap tests with normal findings.
• Continue to promote the need for routine rescreening for breast and cervical cancer at regular intervals to improve rescreening rates for women enrolled in NBCCEDP.

Case-Management Services

• Expand case-management activities to ensure that women enrolled in NBCCEDP receive timely and appropriate rescreening and diagnostic services and treatment services, if indicated.
• Increase case-management activities to sustain networks and partnerships to maximize access to and availability of diagnostic, treatment, and essential support services for women enrolled in NBCCEDP.

Professional Education and Training

• Increase collaboration with professional groups that provide continuing education for their constituents to address breast and cervical cancer control issues in standardized curricula and training.
• Continue to advocate for incorporation of breast and cervical cancer education in curricula for health professionals to facilitate a long-term effect on provider practice.

Partnerships

• Continue to build partnerships with public health departments, tribes and tribal organizations, national and voluntary organizations, academic centers, and health-care purchasers through the following activities: implementing strategies communitywide to promote awareness and screening practices among all women; replicating and disseminating programmatic approaches that are proven effective in providing screening to priority populations (e.g., racial/ethnic minorities and women residing in rural or other hard-to-reach areas); cosponsoring conferences, workshops, and training related to breast and cervical cancer issues; and advocating for breast and cervical cancer control priorities (e.g., policies and standards) to ensure the quality of mammography and Pap screening delivered by all providers.

RESEARCH AGENDA

To support the recommended priority activities for NBCCEDP, CDC has developed a research agenda comprising six priorities. This research will assist in improving cancer screening services provided to women enrolled in NBCCEDP and in developing new methods to recruit eligible women who have rarely or have never received breast or cervical cancer screening.

• Priority: Determine effective strategies to communicate changes in NBCCEDP policy to cancer screening providers and women enrolled in the program. Emerging developments in cancer prevention and control occasionally require substantial changes in program policy (e.g., changing from annual to triennial cervical cancer screening among women with three previous normal Pap tests). Changes in program policy might require adapting the practice patterns of providers and modifying the expectations and behaviors of enrolled women. Research is needed to develop and evaluate effective public and provider education and materials for dissemination that will help translate policy changes into practice as rapidly as possible.
• Priority: Identify effective strategies to increase the proportion of enrolled women who complete routine breast and cervical cancer rescreening according to NBCCEDP policy. Available data submitted twice a year to CDC by participating programs suggest that many women enrolled in NBCCEDP, regardless of their race/ethnicity, do not complete routine rescreening on schedule. Some research is under way in this area, but more is needed. A multiethnic, multicultural focus group study of the barriers to mammography rescreening among NBCCEDP enrollees in Texas (33) resulted in development of an ongoing retrospective cohort investigation among 2,500 randomly selected enrollees in Maryland, New York, Ohio, and Texas. Findings from this research that identify risk factors for failure to rescreen on schedule will be used to develop and test new interventions to increase routine rescreening; however, additional research is needed in this area.
• Priority: Identify effective strategies to increase NBCCEDP enrollment among eligible women who have never received breast or cervical cancer screening. Data from the 1997 BRFSS suggest that substantial numbers of age-eligible, low-income women have never received mammography or Pap smear screening (23). To develop effective outreach and enrollment strategies for women who have rarely or have never received cancer screening, participatory research methods that involve unscreened women and members of their communities in all phases of the research process might be particularly valuable. In addition, quantitative research designs might be necessary to test proposed interventions. Research initiatives related to this priority topic must address both missed screening opportunities in diverse provider settings and various cultural, language, and institutional barriers that might influence a woman's willingness to accept free or low-cost cancer screening when offered.
• Priority: Evaluate variations in clinical practice patterns among providers of NBCCEDP screening services. Analyses of data submitted every 6 months to CDC by participating programs have identified several practice patterns that differ markedly across these programs. These variations raise concern regarding quality assessment. For example, an analysis of mammography results for 1991-1996 reported through the Breast Imaging Reporting and Data System (BI-RADS^®) lexicon developed by the American College of Radiology (34) documented that the proportion of mammograms coded "probably benign, short-term follow-up recommended" varied substantially across the state, territorial, and tribal programs (35). To understand the reasons for such variations and to develop appropriate provider education materials, where necessary, case studies and record linkage investigations within collaborating programs might be necessary. Such studies must be conducted within participating programs because data submitted to CDC cannot be linked with medical records, pathology laboratory reports, or cancer registries.
• Priority: Determine optimal models for providing case-management services to women in NBCCEDP who have an abnormal screening result or a diagnosis of cancer. Without effective case management, some low-income women who need additional cancer testing or treatment will not receive the necessary care or will not receive it as rapidly as possible. Diverse case-management models have been developed for other public health concerns including tuberculosis control, adolescent prenatal care, and human immunodeficiency virus infection/acquired immunodeficiency syndrome. Research is needed to evaluate the applicability of these and other models to low-income, medically uninsured women who need additional cancer testing and treatment. Critical issues include determining how women will be selected for case management, how extensive case-management efforts should be, and what proportion of screening resources should be allocated to case-management activities.
• Priority: Conduct economic analyses to determine costs of providing screening services in NBCCEDP. Because the funds appropriated by Congress to NBCCEDP are not adequate to screen all eligible women who need breast and cervical cancer screening, economic analyses are necessary to enhance efficient use of the available resources. Important issues include the potential cost advantages of high-volume versus low-volume laboratories and mammography facilities, the sustainability of facilities that are providing program-funded screenings below their current cost levels, and the costs and benefits of mammography vans compared with standard facilities.

CONCLUSION

Breast and cervical cancer continue to be major health problems in the United States. Preventive measures are available to reduce morbidity and mortality associated with these diseases. The NBCCEDP, through federal, state, territorial, and tribal governments, in collaboration with national and community-based organizations, has increased access to breast and cervical cancer screening among low-income and uninsured women. In addition, NBCCEDP-sponsored programs have increased the staff working in cancer control and the expertise of these persons, implemented professional education programs for health-care providers, and developed innovative public education and outreach strategies to encourage medically underserved women to seek screening services. This national effort enabled the United States to make substantial progress toward achieving the Healthy People 2000 objectives for breast and cervical cancer control, particularly among racial/ethnic minorities and the medically underserved. However, NBCCEDP still reaches only 12%-15% of uninsured women aged 50-64 years who are eligible for screening services. A continuing challenge for the future is to increase national commitment to providing screening services for all eligible uninsured women to ultimately reduce morbidity and mortality from breast and cervical cancer.

References

1. Institute of Medicine. The unequal burden of cancer: an assessment of NIH research and programs for ethnic minorities and the medically underserved. Haynes MA, Smedley BD, eds. Washington, DC: National Academy Press, 1999:1-2.
2. Greenlee RT, Murray T, Bolden S, Wingo PA. Cancer statistics, 2000. CA Cancer J Clin 2000;50:7-33.
3. Miller BA, Kolonel LN, Bernstein L, et al, eds. Racial/ethnic patterns of cancer in the United States, 19881992. Bethesda, MD: US Department of Health and Human Services, National Institutes of Health, National Cancer Institute, 1996; NIH publication no. 96-4104.
4. Ries LAG, Kosary CL, Hankey BE, et al, eds. SEER cancer statistics review, 1973-1996. Bethesda, MD: US Department of Health and Human Services, National Institutes of Health, National Cancer Institute, 1999.
5. Qualters JR, Lee NC, Smith RA, Aubert RE. Breast and cervical cancer surveillance, United States, 19731987. In: CDC surveillance summaries (April 24). MMWR 1992;41(No. SS-2):1-15.
6. Kelsey JL. Breast cancer epidemiology: summary and future directions. Epidemiol Rev 1993;15:256-63.
7. Natarajan N, Nemoto D, Nemoto T, Mettlin C. Breast cancer survival among Orientals and whites living in the United States. J Surg Oncol 1988;39:206-9.
8. Vernon SW, Tilley BC, Neale AV, Steinfeldt L. Ethnicity, survival, and delay in seeking treatment for symptoms of breast cancer. Cancer 1985;55:1563-71.
9. CDC. Black-white differences in cervical cancer mortality -- United States, 1980-1987. MMWR 1990;39:245-6,248.
10. Brinton LA. Ways that women may possibly reduce their risk of breast cancer. J Natl Cancer Inst 1994;86:371-2.
11. Fisher B, Costantino JP, Wickerham L, et al. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study. J Natl Cancer Inst 1998;90:1371-88.
12. Beral V, Hermon C, Muñoz N, Devesa SS. Cervical cancer. Cancer Surv 1994;19/20:265-85.
13. Schiffman MH, Brinton LA, Devesa SS, Fraumeni Jr JF. Cervical cancer. In: Schottenfeld D, Fraumeni Jr JF, eds. Cancer epidemiology and prevention. 2nd ed. New York, NY: Oxford University Press, 1996:1090-116.
14. US Preventive Services Task Force. Guide to clinical preventive services: report of the U.S. Preventive Services Task Force. 2nd ed. Baltimore, MD: Williams and Wilkins, 1996.
15. Baines CJ, McFarlane DV, Miller AB, collaborating radiologists. Sensitivity and specificity of first screen mammography in 15 NBSS centres. J Can Assoc Radiol 1988;39:273-6.
16. Shapiro S. The status of breast cancer screening: a quarter of a century of research. World J Surg 1989;13:9-18.
17. Fletcher SW, Black W, Harris R, Rimer BK, Shapiro S. Report on the International Workshop on Screening for Breast Cancer. J Natl Cancer Inst 1993;85:1644-56.
18. Kerlikowske K, Grady D, Rubin SM, Sandrock C, Ernster VL. Efficacy of screening mammography: a meta-analysis. JAMA 1995;273:149-54.
19. Wald N, Chamberlain J, Hackshaw A. Consensus conference on breast cancer screening: report of the Evaluation Committee. Oncology 1994;51:380-9.
20. National Institutes of Health. NIH consensus statement: breast cancer screening for women ages 40-49. Bethesda, MD: US Department of Health and Human Services, National Institutes of Health, 1997:1-35. (Vol 15, no. 1).
21. Volkers N. NCI replaces guidelines with statement of evidence. J Natl Cancer Inst 1994;86:14-5.
22. Eastman P. NCI adopts new mammography screening guidelines for women. J Natl Cancer Inst 1997;89:538-40.
23. Blackman DK, Bennett EM, Miller DS. Trends in self-reported use of mammograms (1989-1997) and Papanicolaou tests (1991-1997) -- Behavioral Risk Factor Surveillance System. In: CDC surveillance summaries (October 8). MMWR 1999;48(No. SS-6).
24. Public Health Service. Healthy people 2000: national health promotion and disease prevention objectives -- full report, with commentary. Washington, DC: US Department of Health and Human Services, Public Health Service, 1991; DHHS publication no. (PHS)91-50212.
25. Eddy DM. Screening for cervical cancer. Ann Intern Med 1990;113:214-26.
26. Kurman RJ, Henson DE, Herbst AL, Noller K, Schiffman MH. Interim guidelines for management of abnormal cervical cytology. JAMA 1994;271:1866-9.
27. Miller AB. Cervical cancer screening programmes: managerial guidelines. Geneva, Switzerland: World Health Organization, 1992.
28. Henson RM, Wyatt SW, Lee NC. The National Breast and Cervical Cancer Early Detection Program: a comprehensive public health response to two major health issues for women. Journal Public Health Management Practice 1996;2:36-47.
29. National Institutes of Health. NIH concensus statement: cervical cancer. Bethesda, MD: US Department of Health and Human Services, National Institutes of Health, 1996:1-38. (Vol 14, no. 1).
30. Chattopadhyay SK, Hall HI, Wolf RB, Custer WS. Sources of health insurance in the U.S.: analysis of state-level data and implications for public health programs. J Public Health Management Practice 1996;5:35-46.
31. Shy K, Chu J, Mandelson M, Greer B, Figge D. Papanicolaou smear screening interval and risk of cervical cancer. Obstet Gynecol 1989;74:838-43.
32. Lantz P, Sever LE, Henson R, Lee NC. Strategies for providing follow-up and treatment services in the National Breast and Cervical Cancer Early Detection Program -- United States, 1997. MMWR 1998;47:215-8.
33. Bobo JK, Dean D, Stovall C, Mendez M, Caplan L. Factors that may discourage annual mammography among low-inome women with access to free mammograms: a study using multi-ethnic, multiracial focus groups. Psychol Rep 1999;85;405-16.
34. American College of Radiology. Breast Imaging Reporting and Data System. 2nd ed. Reston, VA: American College of Radiology, 1995.
35. Caplan LS, Blackman D, Nadel M, Monticciolo DL. Coding mammograms using the classification "probably benign finding -- short interval follow-up suggested". AJR Am J Roentgenol 1999;172;339-42.

* Defined as up to 250% of poverty level depending, on family size.

^† In 1996, the SEER program comprised cases from 11 population-based cancer registries throughout the United States that represent an estimated 13.9% of the U.S. population. The SEER program also publishes death rates based on a public-use data tape from CDC's National Center for Health Statistics. During 1988-1996, the 11 locations were Connecticut; Hawaii; Iowa; New Mexico; Utah; and Atlanta, Detroit, San Francisco/Oakland, San Jose/Monterey, Los Angeles, and Seattle/Puget Sound.