Recent trends in U.S. breast cancer incidence, survival, and mortality rates

Increasing mammography among women aged 40-74 by use of a stage-matched, tailored intervention

BACKGROUND

Tailoring is a promising technique for encouraging greater performance of health-related behaviors. Tailored interventions are designed to be more individualized to personal characteristics, in contrast to "standard" interventions where all participants receive the same materials.

METHODS

A total of N = 1864 women aged 40-74 were recruited from a staff model HMO and randomly assigned to one of three intervention groups: (a) No Educational Materials, (b) Standard Materials, and (c) Stage-Matched Materials. A provider-directed component was common across all three conditions. The Standard and Stage-Matched groups each received two mailed educational packets after baseline and follow-up telephone interviews. The Stage-Matched intervention was based on the Transtheoretical Model of behavior change.

RESULTS

Analyses of n = 1397 women (after all attrition) showed that receipt of mammography after the baseline interview was higher for the Stage-Matched group (63.6%) than for the No Materials group (54.9%; OR = 1.43, 95% CI = 1.10, 1.86). The Standard intervention group was intermediate (58. 5%). The Standard group did not differ from the No Materials group, but did differ from the Stage-Matched group in multivariate analysis.

CONCLUSIONS

Stage-matched, tailored materials may be a means to encourage screening mammography. Such interventions can be implemented by telephone and mail.

Outcomes of modern screening mammography

The University of California, San Francisco, Mobile Mammography Screening Program is a low-cost, community-based breast cancer screening program that offers mammography to women of diverse ethnic backgrounds (36% nonwhite) in six counties in northern California. Analysis of data collected on approximately 34,000 screening examinations from this program shows that the positive predictive value and sensitivity of modern screening mammography to be lower for women aged 40 to 49 years compared to women aged 50 and older. This lower performance is due to the lower prevalence of invasive breast cancer in younger women and possibly to age differences in breast tumor biology. Because of this lower performance, women in their forties may be subjected to more of the negative consequences of screening, which include additional diagnostic evaluations and the associated morbidity and anxiety, the potential for detecting and surgically treating clinically insignificant breast lesions, and the false reassurance resulting from normal mammographic results. Since the evidence is not compelling that the benefits of mammography screening outweigh the known risks for women aged 40 to 49 years, women considering mammography screening should be informed of the risks, potential benefits, and limitations of screening mammography, so that they can make individualized decisions based on their personal risk status and utility for the associated risks and potential benefits of screening.

Breast cancer screening among women in their forties: an overview of the issues

This article summarizes the issues prompting a recent NIH Consensus Conference on mammography screening for women in their forties. To date, eight randomized controlled trials of breast cancer screening have been conducted, and a reduction in breast cancer mortality has emerged after 10 to 15 years of follow-up among women offered screening in their forties. No effect appears for at least eight years, and the reason for the delay, compared to that seen in women aged 50-69, is not clear. Two possibilities include cancer-stage shift due to screening in younger women and the aging of women into their fifties during the course of screening. Possible adverse effects of screening include radiation risk, although this is low, false-negative and false-positive screening tests, and overdiagnosis due to detection of ductal carcinoma in situ (DCIS). In order to make appropriate decisions regarding mammography, women need age-related information about both the benefits and potential risks of screening.

Breast Cancer Care: Developments in 1998

BACKGROUND: Breast cancer is a significant cause of mortality and morbidity worldwide, although death rates in the United States and some other countries are beginning to fall. METHODS: Several sources of information in 1998, including publications and presentations at the 1998 meeting of the American Society of Clinical Oncology, are pertinent to contemporary breast cancer care. RESULTS: It is now possible to prescribe hormonal therapy that will reduce the incidence of breast cancer. Methods are available to reduce the morbidity from axillary node dissection, and improvements in adjuvant therapy and management of metastatic breast cancer are now at hand. CONCLUSIONS: The information presented provides a broad-based platform for new standards of care for breast cancer that will serve as a sound base for further progress in this important disease.

Scintimammographic analysis of nonpalpable breast lesions previously identified by conventional mammography

BACKGROUND

In randomized trials, screening mammography has led to decreased mortality from breast cancer. However, the low positive predictive value of mammography (i.e., the proportion of patients with a positive test result who actually have breast cancer) results in a large number of unnecessary biopsies. We determined whether scintimammography with technetium-99m-sestamibi is a useful supplemental diagnostic tool for women with nonpalpable breast abnormalities identified by conventional mammography.

METHODS

Scintimammography was performed preoperatively on 70 women who were 31-66 years of age (mean age and median age = 51 years). These women had nonpalpable breast abnormalities identified by conventional mammography; subsequently, a needle-localization excisional biopsy of each suspicious lesion was performed. Scintimammographic images were interpreted independently by two nuclear medicine physicians who were blinded to all clinical and pathologic data, and an interobserver variation analysis was performed.

RESULTS

Interobserver variation analysis of the scintimammographic findings showed an agreement for breast diagnosis of 97% and a kappa coefficient of 0.90. Comparison of scintimammographic findings and histopathologic results revealed that the sensitivity (proportion of patients with breast cancer who had a positive test result), the specificity (proportion of patients without breast cancer who had a negative test result), the positive predictive value and the negative predictive value (proportion of patients with a negative test result who actually did not have breast cancer) of scintimammography were 56% (95% confidence interval [CI] = 23%-85%), 87% (95% CI = 75%-94%), 38% (95% CI = 15%-68%), and 93% (95% CI = 82%-98%), respectively. Four of nine breast cancers were not detected by scintimammography.

CONCLUSION

Because of excellent interobserver agreement, scintimammography provides an objective way of detecting primary breast carcinoma. In view of its low sensitivity and positive predictive value, however, scintimammography is not currently recommended as a screening test in patients with nonpalpable positive mammographic findings.

Interactions between hormones and chemicals in breast cancer

Development of breast cancer in women is dependent on diverse factors, including genetic predisposition, exposure to both exogenous and endogenous chemicals, which can modulate initiation, promotion and progression of this disease, and the timing of exposure to these agents. Several compounds--including 16 alpha-hydroxyestrone (16 alpha-OHE1), catecholestrogens, and aromatic amines--have been proposed as initiators of mammary carcinogenesis in humans; however, their role as genotoxins is unconfirmed. Lifetime exposure to estrogens has been established as an important risk factor for breast cancer, and it has been suggested that xenoestrogens may directly add to the hormonal risk or indirectly increase risk by decreasing 2-hydroxyestrone (2-OHE1)/16 alpha-OHE1 metabolite ratios. Results of recent studies suggest that chemical-induced modulation of 2-OHE1/16 alpha-OHE1 metabolite ratios is not predictive of xenoestrogens or mammary carcinogens. Moreover, based on current known dietary intakes of natural and xenoestrogenic/antiestrogenic chemicals, it is unlikely that xenoestrogens contribute significantly to a woman's overall lifetime exposure to estrogens. More information is required on the identities and serum levels of both natural and xenoendocrine active compounds, their concentrations in serum, and the mammary gland and levels of these compounds at critical periods of exposure.

Dietary supplement use by women at risk for breast cancer recurrence. The Women's Healthy Eating and Living Study Group

OBJECTIVE

To develop a method of collecting, organizing, and analyzing information on nutrient and nonnutrient dietary supplement use by women at risk for breast cancer recurrence as a component of nutrition assessment and monitoring, and to describe the characteristics associated with dietary supplement use in this population at enrollment in a clinical trial to prevent breast cancer recurrence.

DESIGN

Cross-sectional descriptive study design.

SUBJECTS

Women diagnosed with breast cancer within the previous 4 years (n=435).

ANALYSIS

Dietary supplements reported in four 24-hour dietary recalls were categorized according to primary nutrient and nonnutrient contents. Prevalence of dietary supplement use is described. Associations between supplement use and demographic and participant characteristics were examined using chi(2) analysis and logistic regression.

RESULTS

Dietary supplement use was reported by 80.9% of the women. Increased likelihood of supplement use was associated with demographic (eg, older age, higher level of education, white race vs other ethnic groups) and personal (eg, lower body mass index, moderate alcohol consumption) characteristics. Use of vitamin C and related compounds, other nutrients (eg, n-3 fatty acids, evening primrose oil), and herbal products was inversely associated with months since diagnosis; use of miscellaneous supplements (eg, shark cartilage) was directly associated with more advanced stage at diagnosis.

APPLICATIONS

Monitoring dietary supplement use is an important aspect of nutrition assessment, especially in populations with chronic health conditions or medical diagnoses. Demographic and personal characteristics, time passed since diagnosis, and stage of cancer at diagnosis are predictive of dietary supplement use by women at risk for breast cancer recurrence. Associations in this population may be present in other groups that are the object of nutrition intervention efforts.

Geographic variations in breast cancer mortality: do higher rates imply elevated incidence or poorer survival?

OBJECTIVES

Mortality rates from breast cancer are approximately 25% higher for women in the northeastern United States than for women in the South or West. This study examined the hypothesis that the elevation is due to decreased survival rather than increased incidence.

METHODS

Data on breast cancer incidence, treatment, and mortality were reviewed.

RESULTS

The elevated mortality in the Northeast is apparent only in older women. For women aged 65 years and older, breast cancer mortality is 26% higher in New England than in the South, while incidence is only 3% higher. Breast cancer mortality for older women by state correlates poorly with incidence (r = 0.28).

CONCLUSIONS

Those seeking to explain the excess breast cancer mortality in the Northeast should assess survival and should examine differences in cancer control practices that affect survival.

Much ado about not...enough data: high-dose chemotherapy with autologous stem cell rescue for breast cancer

High-dose chemotherapy with autologous bone marrow or stem cell rescue (HDC/ASCR) has been proposed as a promising treatment strategy for breast cancer. Despite the frequency with which this procedure is performed, the role of HDC/ASCR in the treatment of breast cancer remains undefined. The purpose of this review is to examine the rationale for the procedure, the research progress to date, and the limitations of available data. A literature search of Medline from January 1966 through May 1997, CancerLit from January 1983 through May 1997, and Current Contents through May 1997 identified more than 600 English language papers or abstracts on this topic. Our review focuses on the preclinical and clinical data that explore the concept of chemotherapy dose intensity and the role of dose intensity in treating breast cancer. HDC/ASCR is based on the hypothesis that high-dose chemotherapy will overcome drug resistance, eradicate metastatic disease, and increase the proportion of women with breast cancer who are "cured." To date, results from only one phase 3 trial of HDC/ASCR compared with more conventional therapy have been published. Phase 2 and some phase 3 data on HDC/ASCR in the treatment of high-risk primary breast cancer and metastatic breast cancer are discussed. However, the results are inconclusive. The completion of national and international randomized trials is urgently needed to establish definitively the role of HDC/ASCR in the treatment of breast cancer.

Breast cancer mortality trends in Australia: 1921 to 1994

OBJECTIVE

To analyse breast cancer mortality trends in Australia and to see if mammographic screening has yet led to a reduction in mortality.

DESIGN

Retrospective analysis of trends in mortality rates from breast cancer in Australian women between 1921 and 1994, and in potentially explanatory variables such as fertility, body size, age at menarche, and screening.

RESULTS

Changes in breast cancer mortality in Australian women could not be explained by chance variation alone. Mortality rose steadily (average annual increase, 1.0%) to 1940-1944, fell to the 1960s and early 1970s, and rose (average annual increase, 0.3%) to the late 1980s. Between 1985-1989 and 1990-1994, breast cancer mortality fell by 3.2% in women 50-69 years of age (the target age group for mammographic screening) and by 4.2% in women 25-49 years of age. There was almost on change (-0.2%) in breast cancer mortality in older women in this period. The proportion of women screened in all age groups increased substantially between 1988 and 1994; nearly 65% of women in the target age group had had at least one mammogram by 1994. Decreases in fertility were followed by increases in mortality, and vice versa.

CONCLUSIONS

Trends in breast cancer mortality have probably been influenced by changing fertility, nutrition and body-size increases among Australian women. Improvements in stage at diagnosis and treatment have probably moderated the upwards pressure on mortality caused by an increasing incidence. Recent falls in mortality could be expected to continue as more women participate in the mammographic screening program. This trend should be more clearly evident in the second half of the 1990s.

Recent trends in breast cancer incidence in Sweden

Breast cancer incidence in Sweden during the period 1984-93 shows no clear trend in women aged below 40 years but a transient increase at ages 50-69 years, probably as a result of mammography screening. Our data give no indication that use of oral contraceptives or replacement hormones have affected nationwide breast cancer incidence rates.

Birth cohort and calendar period trends in breast cancer mortality in the United States and Canada

BACKGROUND

Previous studies of regional and temporal variation in U.S. breast cancer mortality rates have been confined largely to analyses of rates for white women.

PURPOSE

Breast cancer mortality rates from 1969 through 1992 for white women and black women in four regions of the United States and for all women throughout Canada were compared to identify racial, regional, and temporal differences. Differences and trends in the rates were evaluated in view of breast cancer risk factors and relevant medical interventions.

METHODS

Age-period-cohort models were fit to the data, and changes in birth cohort trends (suggesting a change in a breast cancer risk factor or protective factor) and calendar period trends (suggesting, in part, the impact of new or improved medical interventions) were examined.

RESULTS

Breast cancer mortality rates for white women were significantly higher in the Northeast than in any other region of the United States (two-sided t tests; P<.005); the rates for black women were not. Birth cohort trends for all women were similar until about 1940, with a moderation of mortality risk beginning around 1924. A marked moderation of risk by 4-year birth cohorts was observed for U.S. white women born after 1950, whereas stable or slightly decreasing trends were observed for U.S. black women and Canadian women. For women born from 1924 to around 1938, fertility rates increased for all three groups; after 1950, they declined uniformly. Looking at temporal effects, we found that the slope of the mortality calendar period trend increased in the 1980s compared with the 1970s for all women. In the last calendar period, 1991-1992, a trend of decreasing mortality rates was found for white women in the United States and for Canadian women.

IMPLICATIONS

Widespread environmental exposures are unlikely to explain the higher relative breast cancer mortality rates observed for U.S. white women in the Northeast, since the rates for black women in this region were not higher than in other regions. The moderation of breast cancer mortality rates for women born between 1924 and 1938 coincides with increased fertility rates following World War II. Stable or decreasing mortality rates for U.S. women and Canadian women born after 1950 were not expected in view of declining fertility rates, suggesting a change in a breast cancer risk factor or protective factor. The increase in calendar period trend slope in the 1980s likely reflects the coincident rise in breast cancer diagnosis via mammography. The recent decline in calendar period trend for white women in the United States and for Canadian women may be the result of earlier detection and increased use of adjuvant therapy.