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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 [is less than] .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. [J Natl Cancer Inst 1998;90:906-10]

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. [J. Natl Cancer Inst 1997;89:1683-91]

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

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

The increased uses of mammography and breast physical examination are part of the early detection objectives of the National Cancer Institute and have become a national priority. However, there are limitations in resources, mammographic equipment, and trained personnel. One approach has been to limit mammographic screening to women who belong to increased risk groups. Unfortunately, research has shown this technique to be ineffective, since it fails to include a large number of women who are likely to develop breast cancer. A more workable solution is to vary the recommended interval of mammographic screening, depending upon the risk category of the individual. This method has several advantages. More women are recommended to have mammographic screening, and yet the total number of screenings need not increase. In addition, the small but finite risks of mammographic screening are more concentrated among the women who are also the most likely to benefit. (The risks of the screening itself are, in fact, smaller than the risks involved with following up what would otherwise turn out to be false positives reports.) Such a program of risk determination has been instituted in a large northwest health maintenance organization (HMO) serving 400,000 members. After completing a questionnaire and noting such factors as age of first menstruation, nulliparity, first birth over 30, breast cancer in a first degree relative, and so forth, the woman is assigned to one of four risk categories. Women in the lowest category have mammography only when referred by their physician. In the next three categories, women are suggested to have mammographic exams at five-, three-, and one-year intervals. The net result is that within this HMO the number of mammographic exams has not increased, but the percentage of women over 40 who are eligible for mammography has risen from 57 to 83 percent. (Consumer Summary produced by Reliance Medical Information, Inc.)