Effect of estrogen replacement therapy on the specificity and sensitivity of screening mammography.

BACKGROUND: Previous studies have demonstrated that mammographic breast density increases following the initiation of estrogen replacement therapy (ERT). The effect, if any, that this increase in density has on the specificity (related to false-positive readings) and the sensitivity (related to false-negative readings) of screening mammography is unknown. PURPOSE: Using a retrospective cohort study design, we assessed the effects of ERT on the specificity and the sensitivity of screening mammography. METHODS: Participants (n = 8779) were postmenopausal women, aged 50 years or older, who were enrolled in a health maintenance organization located in western Washington state and who entered a breast cancer screening program between January 1988 and June 1993. Two-view mammography was performed as part of a comprehensive breast cancer screening visit. Menopausal status, as well as demographic and risk-factor information, was recorded via self-administered questionnaires. Hormonal replacement therapy type and use were determined from questionnaire data and from an automated review of pharmacy records. Individuals diagnosed with breast cancer within 12 months of their first screening-program mammograms were identified through use of a regional cancer registry. Risk ratios (RRs) plus 95% confidence intervals (CIs) of false-positive as well as false-negative examinations among current and former ERT users (with never users as the reference group) were calculated. Reported P values are two-sided. RESULTS: The specificity of mammographic screening was lower for current users of ERT than for never users or former users. Defining a positive mammographic reading as any non-normal reading (either suspicious for cancer or indeterminate), the adjusted RR (95% CI) of a false-positive reading for current users versus never users was 1.33 (1.15-1.54) (P < .001); for former users versus never users, the RR (95% CI) was 1.00 (0.87-1.15). The adjusted mammographic specificities (95% CIs) for never users, former users, and current users of ERT were 86% (84%-88%), 86% (84%-87%), and 82% (80%-84%), respectively. Defining a positive reading more rigorously (i.e., as suspicious for cancer only), the adjusted RRs (95% CIs) of false-positive readings for current users and former users (versus never users) were 1.71 (1.37-2.14) (P < .001) and 1.16 (0.93-1.45), respectively. Sensitivity was also lower in women currently receiving ERT. The unadjusted RR (95% CI) of a false-negative reading for current users versus never users was 5.23 (1.09-25.02) (P = .04); for former users versus never users, the RR (95% CI) was 1.06 (0.10-10.87). The unadjusted mammographic sensitivities (95% CI) for never users, former users, and current users of ERT were 94% (80%-99%), 94% (69%-99%), and 69% (38%-91%), respectively. CONCLUSIONS AND IMPLICATIONS: Current use of ERT is associated with lower specificity and lower sensitivity of screening mammography. Lower specificity could increase the cost of breast cancer screening, and lower sensitivity may decrease its effectiveness.

Stage, age, comorbidity, and direct costs of colon, prostate, and breast cancer care.

PURPOSE: This study was conducted to evaluate the effect of stage at diagnosis, age, and level of comorbidity (presence of other illness) on the costs of treating three types of cancer among members of a health maintenance organization. METHODS: Among 388,000 members enrolled anytime during 1990 and 1991 in Group Health Cooperative (GHC) of Puget Sound (Washington State), we estimated the total and net direct costs of medical care for colon, prostate, and breast cancers, including both incident (290, 554, and 645 patients, respectively) and prevalent (1046, 1295, and 2299 patients, respectively) cases. We summarized costs for initial, continuing, and terminal phases of care. Net costs were the difference between the costs of the care of each case subject and the average costs of the care for all enrollees without the cancer of interest who were of the same sex and in the same 5-year age group. Differences in estimated total and net costs by stage at diagnosis, age, and comorbidity were separately evaluated using multivariate regression modeling. All P values were two-sided. Comorbidity was based on a score calculated from 1988 pharmacy data. RESULTS: Total costs of initial care increased with stage at diagnosis for colon (P = .0013) and breast (P < .0001) cancer cases, but not for prostate cancer cases. Total initial costs decreased with age for prostate (P = .0225) and breast (P = .0002) cancers but did not change with degree of comorbidity for any of the three cancers. Total continuing medical care costs increased with stage at diagnosis for colon (P < .0001) and breast (P < .0001) cancer cases but not for prostate cancer cases. Total terminal care costs were similar by stage for all three cancers. Net initial costs differed with stage for all three cancers (P < .05). Net continuing care costs increased with stage (P < .0001) and decreased with age (P < .001) for colon and breast cancers but not for prostate cancer. Net continuing care costs decreased with comorbidity for all three cancers (P = .004, P = .011, and P < .0001 for colon, prostate, and breast cancers, respectively). Among regional stage cancers, continuing care costs decreased with age for colon (P < .0017) and breast (P = .033) cancers but not for prostate cancers. CONCLUSIONS: The results show that total costs vary by stage at diagnosis and age, but the patterns of variation differ for each cancer. Costs of cancer are not simply additive to costs of other conditions. IMPLICATIONS: More needs to be done to explore the reasons and implications of age-related cost differences. Cost-effectiveness analyses of cancer control interventions that shift cancer stage distributions may need to consider both the age and comorbidity of the target populations.

Cost comparison of mastectomy versus breast-conserving therapy for early-stage breast cancer.

BACKGROUND: Choice of treatment for early-stage breast cancer depends on many factors, including the size and stage of the cancer, the woman's age, comorbid conditions, and perhaps the costs of treatment. We compared the costs of all medical care for women with early-stage breast cancer cases treated by breast-conserving therapy (BCT) or mastectomy. METHODS: A total of 1675 women 35 years old or older with incident early-stage breast cancer were identified in a large regional nonprofit health maintenance organization in the period 1990 through 1997. The women were treated with mastectomy only (n = 183), mastectomy with adjuvant hormonal therapy or chemotherapy (n = 417), BCT with radiation therapy (n = 405), or BCT with radiation therapy and adjuvant hormonal therapy or chemotherapy (n = 670). The costs of all medical care for the period 1990 through 1998 were computed for each woman, and monthly costs were analyzed by treatment, adjusting for age and cancer stage. All statistical tests were two-sided. RESULTS: At 6 months after diagnosis, the mean total medical care costs for the four groups differed statistically significantly (P:<.001), with BCT being more expensive than mastectomy. The adjusted mean costs were $12 987, $14 309, $14 963, and $15 779 for mastectomy alone, mastectomy with adjuvant therapy, BCT plus radiation therapy, and BCT plus radiation therapy with adjuvant therapy, respectively. At 1 year, the difference in costs was still statistically significant (P:<.001), but costs were influenced more by the use of adjuvant therapy than by type of surgery. The 1-year adjusted mean costs were $16 704, $18 856, $17 344, and $19 081, respectively, for the four groups. By 5 years, BCT was less expensive than mastectomy (P:<.001), with 5-year adjusted mean costs of $41 930, $45 670, $35 787, and $39 926, respectively. Costs also varied by age, with women under 65 years having higher treatment costs than older women. CONCLUSIONS: BCT may have higher short-term costs but lower long-term costs than mastectomy.

Testing reminder and motivational telephone calls to increase screening mammography: a randomized study.

BACKGROUND: Prospective randomized trials have demonstrated that motivational telephone calls increase adherence to screening mammography. To better understand the effects of motivational calls and to maximize adherence, we conducted a randomized trial among women aged 50-79 years. METHODS: We created a stratified random sample of 5062 women due for mammograms within the Group Health Cooperative of Puget Sound, including 4099 women with prior mammography and 963 without it. We recruited and surveyed 3743 (74%) of the women before mailing a recommendation. After 2 months, 1765 (47%) of the 3743 women had not scheduled a mammogram and were randomly assigned to one of three intervention groups: a reminder post-card group (n = 590), a reminder telephone call group (n = 585), and a motivational telephone call addressing barriers group (n = 590). The telephone callers could schedule mammography. We used Cox proportional hazards models to estimate the hazard ratio (HR) and 95% confidence interval (CI) for documented mammography use by 1 year. RESULTS: Women who received reminder calls were more likely to get mammograms (HR = 1.9; 95% CI = 1.6-2.4) than women who were mailed postcards. The motivational and reminder calls (average length, 8.5 and 3.1 minutes, respectively) had equivalent effects (HR = 0.97; 95% CI = 0.8-1.2). After we controlled for the intervention effect, women with prior mammography (n = 1277) were much more likely to get a mammogram (HR = 3.4; 95% CI = 2.7-4.3) than women without prior use (n = 488). Higher income, but not race or more education, was associated with higher adherence. CONCLUSIONS: Reminding women to schedule an appointment was as efficacious as addressing barriers. Simple intervention groups should be included as comparison groups in randomized trials so that we better understand more complex intervention effects.

Breast cancer survival and treatment in health maintenance organization and fee-for-service settings.

BACKGROUND: Enrollment in health maintenance organizations (HMOs) has increased rapidly during the past 10 years, reflecting a growing emphasis on health care cost containment. To determine whether there is a difference in the treatment and outcome for female patients with breast cancer enrolled in HMOs versus a fee-for-service setting, we compared the 10-year survival and initial treatment of patients with breast cancer enrolled in both types of plans. METHODS: With the use of tumor registries covering the greater San Francisco-Oakland and Seattle-Puget Sound areas, respectively, we obtained information on the treatment and outcome for 13,358 female patients with breast cancer, aged 65 years and older, diagnosed between 1985 and 1992. We linked registry information with Medicare data and data from the two large HMOs included in the study. We compared the survival and treatment differences between HMO and fee-for-service care after adjusting for tumor stage, comorbidity, and sociodemographic characteristics. RESULTS: In San Francisco-Oakland, the 10-year adjusted risk ratio for breast cancer deaths among HMO patients compared with fee-for-service patients was 0.71 (95% confidence interval [CI] = 0.59-0.87) and was comparable for all deaths. In Seattle-Puget Sound, the risk ratio for breast cancer deaths was 1.01 (95% CI = 0.77-1.33) but somewhat lower for all deaths. Women enrolled in HMOs were more likely to receive breast-conserving surgery than women in fee-for-service (odds ratio = 1.55 in San Francisco-Oakland; 3.39 in Seattle). HMO enrollees undergoing breast-conserving surgery were also more likely to receive adjuvant radiotherapy (San Francisco-Oakland odds ratio = 2.49; Seattle odds ratio = 4.62). CONCLUSIONS: Long-term survival outcomes in the two prepaid group practice HMOs in this study were at least equal to, and possibly better than, outcomes in the fee-for-service system. In addition, the use of recommended therapy for early stage breast cancer was more frequent in the two HMOs.

Variation in mammographic breast density by time in menstrual cycle among women aged 40-49 years.

BACKGROUND: Mammography is less effective for women aged 40-49 years than for older women, which has led to a call for research to improve the performance of screening mammography for younger women. One factor that may influence the performance of mammography is breast density. Younger women have greater mammographic breast density on average, and increased breast density increases the likelihood of false-negative and false-positive mammograms. We investigated whether breast density varies according to time in a woman's menstrual cycle. METHODS: Premenopausal women aged 40-49 years who were not on exogenous hormones and who had a screening mammogram at a large health maintenance organization during 1996 were studied (n = 2591). Time in the menstrual cycle was based on the woman's self-reported last menstrual bleeding and usual cycle length. RESULTS: A smaller proportion of women had "extremely dense" breasts during the follicular phase of their menstrual cycle (24% for week 1 and 23% for week 2) than during the luteal phase (28% for both weeks 3 and 4) (two-sided P = .04 for the difference in breast density between the phases, adjusted for body mass index). The relationship was stronger for women whose body mass index was less than or equal to the median (two-sided P<.01), the group who have the greatest breast density. CONCLUSIONS/IMPLICATIONS: These findings are consistent with previous evidence suggesting that scheduling a woman's mammogram during the follicular phase (first and second week) of her menstrual cycle instead of during the luteal phase (third and fourth week) may improve the accuracy of mammography for premenopausal women in their forties. Breast tissue is less radiographically dense in the follicular phase than in the luteal phase.

Breast density as a predictor of mammographic detection: comparison of interval- and screen-detected cancers.

BACKGROUND: Screening mammography is the best method to reduce mortality from breast cancer, yet some breast cancers cannot be detected by mammography. Cancers diagnosed after a negative mammogram are known as interval cancers. This study investigated whether mammographic breast density is related to the risk of interval cancer. METHODS: Subjects were selected from women participating in mammographic screening from 1988 through 1993 in a large health maintenance organization based in Seattle, WA. Women were eligible for the study if they had been diagnosed with a first primary invasive breast cancer within 24 months of a screening mammogram and before a subsequent one. Interval cancer case subjects (n = 149) were women whose breast cancer occurred after a negative or benign mammographic assessment. Screen-detected control subjects (n = 388) were diagnosed after a positive screening mammogram. One radiologist, who was blinded to cancer status, assessed breast density by use of the American College of Radiology Breast Imaging Reporting and Data System. RESULTS: Mammographic sensitivity (i.e., the ability of mammography to detect a cancer) was 80% among women with predominantly fatty breasts but just 30% in women with extremely dense breasts. The odds ratio (OR) for interval cancer among women with extremely dense breasts was 6.14 (95% confidence interval [CI] = 1.95-19.4), compared with women with extremely fatty breasts, after adjustment for age at index mammogram, menopausal status, use of hormone replacement therapy, and body mass index. When only those interval cancer cases confirmed by retrospective review of index mammograms were considered, the OR increased to 9.47 (95% CI = 2.78-32.3). CONCLUSION: Mammographic breast density appears to be a major risk factor for interval cancer.

Repeat mammography use among women ages 50-75.

It has been demonstrated clearly that the use of regular screening mammography reduces mortality among women ages 50 years and over. The primary objective of this study was to investigate factors associated with repeat mammography participation. A random sample of women ages 50-75 years residing in four Washington State counties was surveyed by telephone during mid-1989. The Health Belief Model was used as a conceptual framework for the analysis. Three groups of women with different mammography experiences in the previous 5 years were compared: (a) nonusers; (b) onetime users; and (c) repeat users. The survey response rate was 72%, and the study sample included 1357 women. One time users were more likely to have health insurance coverage, to visit a gynecologist or other primary care physician regularly, and to believe mammography is more effective than breast self-examination; they were less likely to think that at least 1 in 10 women are diagnosed with breast cancer or that mammography is inconvenient to obtain than were nonusers. Factors associated with repeat versus onetime use included routinely visiting a gynecologist, thinking the lifetime risk of breast cancer is at least 10%, and perceiving a high personal susceptibility to disease. Women who perceive themselves as being vulnerable to breast cancer are more likely to report repeat mammograms. Visiting a gynecologist regularly is associated with repeat as well as initial mammography use. These factors could be considered as the focus of promotional efforts moves from encouraging women to obtain their first mammogram to encouraging repeat use.

Mammography diffusion and trends in late-stage breast cancer: evaluating outcomes in a population.

The purpose of this study was to assess mammography diffusion in a population offered an organized breast cancer screening program, using intervals of 1-3 years, and to evaluate its effect on the late-stage cancer (tumors > or = 3 cm2) rates compared to rates in the surrounding community. We measured "ever-use" of mammography (1986-1992) among women enrollees of a consumer-controlled health care organization (n > or = 60,000/year; ages > or = 40), Group Health Cooperative of Puget Sound (GHC). Among these same women and the surrounding community (n = > or = 745,000/year), we measured late-stage cancer rates. Using unconditional logistic regression, we compared annual rates of ever-use among GHC women ages 40-49 and > or = 50 (1986-1992) and late-stage breast cancer (1983/84-1991/92) among all women. Among all GHC women ages 40 to 49, and 50 years of age and older, 67.4 and 82.8%, respectively, ever-used mammography by 1992. By 1992, approximately one-third of the mammograms among GHC women occurred in each of the three previous years. The rate of late-stage tumors declined significantly in the GHC and non-GHC populations among women 50 years of age and older (P < 0.001) but not among women ages 40 to 49. In conclusion, implementing a system of automated reminders was not sufficient to maximize mammography use in a population. Reductions in late-stage disease occurred among women ages > or = 50, even when regular" was not synonymous with "annual."

Survival and treatment for colorectal cancer Medicare patients in two group/staff health maintenance organizations and the fee-for-service setting.

The current study compares treatment use and long-term survival in colorectal cancer patients between Medicare beneficiaries enrolled in two large prepaid group/staff health maintenance organizations (HMOs) and the fee-for-service (FFS) setting. The study is based on 15,352 colorectal cancer cases diagnosed between 1985 and 1992 and followed through 1995. Survival differences between the HMO and FFS cases were assessed using Cox regression. Treatment differences were evaluated using logistic regression. HMO cases had a lower overall mortality than did FFS cases but not a significantly lower colorectal cancer-specific mortality. Use of surgical resection was similar between HMO and FFS cases. However, rectal cancer cases in the HMOs were more likely to receive postsurgical radiation therapy than FFS cases. Superior overall survival in the HMOs may be the result of increased colorectal cancer screening, greater use of adjuvant therapies, and selection of healthier individuals.

Prostate cancer treatment and ten-year survival among group/staff HMO and fee-for-service Medicare patients.

OBJECTIVE: To compare treatment patterns and the ten-year survival of prostate cancer patients in two large, nonprofit, group/staff HMOs to those of patients receiving care in the fee-for-service health setting. DATA SOURCES/STUDY DESIGN: A cohort of men age 65 and over diagnosed with prostate cancer between 1985 and the end of 1992 and followed through 1994. Subjects (n = 21,741) were ascertained by two population-based tumor registries covering the greater San Francisco-Oakland and Seattle-Puget Sound areas. Linkage of registry data with Medicare claims data and with HMO inpatient utilization data allowed the determination of health plan enrollment and the measurement of comorbid conditions. Multivariate regression models were used to examine HMO versus FFS treatment and survival differences adjusting for sociodemographic and clinical characteristics. PRINCIPAL FINDINGS: Among cases with non-metastatic prostate cancer, HMO patients were more likely than FFS patients to receive aggressive therapy (either prostatectomy or radiation) in San Francisco-Oakland (odds ratio [OR] = 1.69, 95% CI = 1.46-1.96) but not in Seattle (OR = 1.15, 0.93-1.43). Among men receiving aggressive therapy, HMO cases were three to five times more likely to receive radiation therapy than prostatectomy. Overall mortality was equivalent over ten years (HMO versus FFS mortality risk ratio [RR] = 1.01, 0.94-1.08), but prostate cancer mortality was higher for HMO cases than for FFS cases (RR = 1.25, 1.13-1.39). CONCLUSION: Despite marked treatment differences for clinically localized prostate cancer, overall ten-year survival for patients enrolled in two nonprofit group/staff HMOs was equivalent to survival among patients receiving care in the FFS setting, even after adjustment for sociodemographic and clinical characteristics. Similar overall but better prostate cancer-specific survival among FFS patients is most plausibly explained by differences between the HMO and FFS patients in both tumor characteristics and unmeasured patient selection factors.

A test of an expanded theory of reasoned action to predict mammography participation.

This paper presents the results of a prospective study testing an expanded theory of reasoned action (TRA) to predict mammography participation. A questionnaire was developed to measure each of the expanded TRA model components. A sample was identified of 946 women age 40 and above who were invited to obtain a mammogram at the Group Health Cooperative of Puget Sound Breast Cancer Screening Program (BCSP). The sample was stratified by risk category as determined by the screening program. The study questionnaire was administered to all women in the sample within 2 weeks after they were sent the invitation to obtain a mammogram. Mammography participation was obtained from the BCSP data base 6 months after the invitation. Regression analyses found attitude, affect, subjective norm, and facilitating conditions to all be significantly associated with participation. The expanded TRA model explained 39% of the variance in women's intentions and 20% of the variance in participation behavior. A stepwise hierarchical regression found that no other psychosocial measures were able to improve the model predictions of behavior. An interaction between habit and intention was found such that women with larger numbers of previous mammograms were less likely to carry out their intentions than women with fewer previous mammograms. Contrary to expectations, some demographic characteristics did significantly improve prediction. The need for further work investigating the roles of fear and experience is discussed.

Medical community involvement in a breast cancer screening promotional project.

The analysis, mobilization, and involvement of medical communities in two counties targeted for intervention by the Washington State Community Breast Cancer Screening Project is described. Principles of community organization were applied to the health care sectors in the counties, and the PRECEDE-PROCEED model was used as a conceptual framework for considering individual physician behavior. Quantitative and qualitative medical community assessment methods included a demographic study, a survey of primary care physicians, personal interviews with physicians, and medical office staff focus groups. In both intervention areas, physician planning groups selected, developed, and helped implement intervention activities targeting the health care sectors. These activities included informational mailings to physicians, training of medical office staff members and clinical mammographers, and support for a reminder system. The experience demonstrated that physicians practicing in medium-sized cities are willing to be active in community disease prevention programs.

Implementation of outreach telephone counseling to promote mammography participation.

To increase mammography participation, the authors implemented an outreach intervention translating concepts from expectancy value theory into a motivational interviewing telephone intervention that included the opportunity to schedule a screening appointment. Process data are presented from 491 women who had not scheduled a mammogram within 2 months of receiving a mailed invitation from a managed care organization's centralized breast cancer screening program. A total of 83% of targeted women accepted the counseling calls. Counselors rated 84% of completed calls as either receptive or neutral in tone. Women with prior mammography experience were more likely to be receptive and to schedule a screening appointment during the calls than were women with no prior experience. Topics discussed during the calls also differed between women with and without prior mammography experience. Implications for dissemination of counseling interventions in health care organizations are discussed.

Principles of cancer screening for clinicians.

This chapter has outlined some principles of tumor growth, test characteristics, and the evaluation of screening technologies. We have emphasized that test specificity is the critical parameter in the evaluation of technologies because it is the healthy people who will suffer the most from the adverse effects of screening. We have also emphasized that the efficacy of a test is best evaluated by examining mortality reductions in comparable populations. The purpose has been to assist clinicians with their interpretation of the literature. Busy clinicians may not always have the time or inclination to do this themselves. In those cases they need to examine how organizations who make recommendations are coming to their conclusions because it is physicians, not organizations that will do the screening. In particular, it is important to ask the following: (1) Were criteria followed to justify the recommendations being made? (2) If so, what were they, and can the organization demonstrate that they are being met? (3) What perspectives and biases do the organizations bring to the judgments they inevitably have to make? (4) Do you share those perspectives? and (5) When the recommendation is adopted, can you guarantee that it will "first do no harm."

Attitudes, age, and participation in mammographic screening: a prospective analysis.

BACKGROUND: To address the needs of older women, we investigated age-specific attitudes toward mammography that might be influenced by written or verbal communications. METHODS: Attitudinal scores for women aged 40 through 64 years and 65 years and older were calculated prospectively from responses to a mailed questionnaire based on the theory of reasoned action. Age-group mean scores were compared using t-tests for eight components of the attitude measure. Score correlations with participation were compared between age groups using multivariate analysis. RESULTS: Of the 919 eligible women, 666 (72 percent) completed the study questionnaire, and 433 (65 percent) of the 666 women obtained mammograms. A woman aged 65 years or older was less likely to believe that mammography could find a cancer that she (P < 0.01) or her physician (P < 0.05) could not find, and she valued this characteristic less than a younger woman in each instance (P < 0.01). The belief that mammography involved asymptomatic detection was more highly correlated with participation in older women (P < 0.05), as was the attitude that mammography was unfamiliar, but acceptable (P < 0.05). CONCLUSIONS: Older women are less likely to understand that mammography can find cancers that might be missed by other screening methods. Communications to encourage mammography among older women should explain its strengths and familiarize them with the procedure. Communications to younger women need to consider other factors.

Health promotion in an HMO. Ad astra per aspera.

The shift in emphasis towards disease prevention and health promotion is forcing changes in the traditional health provider model. At Group Health Cooperative of Puget Sound (GHC), a 349,000 member staff model HMO, consensus development on health promotion issues is the responsibility of a permanent Committee on Prevention (COP). By spreading the workload over multiple subcommittees that involve cross-sections of the medical, nursing, and other professional staff, the COP has prepared the groundwork for a number of major health care decisions at GHC. The COP has also been the starting point for programs such as the GHC Breast Cancer Screening Program, colon cancer screening, a senior influenza immunization program, and an institutional ban on smoking.

Cost-justification analysis of prenatal maternal serum alpha-feto protein screening.

The costs to an insurer of a 10-year maternal serum alpha-feto protein (MSAFP) screening program were subtracted from future medical care costs avoided by the insurer (benefits) to examine whether such a program would be cost-justified from the perspective of a managed health care system (i.e., result in net costs greater than or equal to 0). The analysis considered MSAFP screening for neural tube defects (NTDs) alone and then was repeated to consider screening for both NTDs and Down's syndrome. Using a 5% discount rate for future dollars, the costs to the insurer of a screening program for NTDs alone over 10 years exceeded costs avoided by $10.00 per person screened. Adding screening for Down's syndrome using the same MSAFP test increased the net cost by $22.00 to a total of--$32.00 per screenee. The estimate of the cost to the insurer was sensitive to assumptions regarding the costs of medical care avoided, the expense of MSAFP, the proportion of screened women requiring a genetic amniocentesis, and the cost of that procedure. The conclusion that screening would not result in a cost savings to the insurer was not changed by reasonable assumptions regarding 1) the appropriate discount rate; 2) the costs of MSAFP; 3) the costs of genetic amniocentesis; 4) the sensitivity of MSAFP; 5) the proportion of the population requiring genetic amniocentesis; and 6) the costs of 10 years of medical care for someone affected by Down's syndrome or an NTD. Other analyses suggested that screening for NTDs or Down's syndrome would be cost-justified when viewed from the perspective of society. The present work suggests this conclusion does not hold when the perspective of the insurer is taken because avoided costs of care realized by society exceed those realized by the insurer.