Race, anthropometric factors, and stage at diagnosis of breast cancer

Obesity, tamoxifen use, and outcomes in women with estrogen receptor-positive early-stage breast cancer

BACKGROUND

Obesity is associated with both increased breast cancer risk and poorer prognosis after disease onset. However, little is known about the effect of obesity on treatment efficacy. We evaluated the association of obesity with outcomes and with tamoxifen efficacy in women with early-stage, hormone-responsive breast cancer participating in a multicenter cancer cooperative group clinical trial.

METHODS

The cohort consisted of 3385 women enrolled in National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol B-14, a randomized, placebo-controlled trial evaluating tamoxifen for lymph node-negative, estrogen receptor (ER)-positive breast cancer. Hazards of breast cancer recurrence, contralateral breast tumors, other new primary cancers, and several mortality endpoints were evaluated in relation to body mass index (BMI), using statistical modeling to adjust for other prognostic factors. Median follow-up time was 166 months. All statistical tests were two-sided.

RESULTS

The hazard of breast cancer recurrence was the same among obese (BMI > or =30.0 kg/m2) women as compared with underweight and normal-weight women (BMI <25.0; hazard ratio [HR] = 0.98, 95% confidence interval [CI] = 0.80 to 1.18). Contralateral breast cancer hazard was higher in obese women than in underweight/normal-weight women (HR = 1.58, 95% CI = 1.10 to 2.25), as was the risk of other primary cancers (HR = 1.62, 95% CI = 1.16 to 2.24). Compared with normal-weight women, obese women had greater all-cause mortality (HR = 1.31, 95% CI = 1.12 to 1.54) and greater risk of deaths due to causes unrelated to breast cancer (HR = 1.49, 95% CI = 1.15 to 1.92). Breast cancer mortality was not statistically significantly increased for obese women (HR = 1.20, 95% CI = 0.97 to 1.49). Tamoxifen reduced breast cancer recurrence and mortality, regardless of BMI.

CONCLUSIONS

For women with lymph node-negative, ER-positive breast cancer, obesity was not associated with a material increase in recurrence risk or a change in tamoxifen efficacy. However, because obesity was associated with increased risks of contralateral breast cancer, of other primary cancers, and of overall mortality, it may influence long-term outcomes for breast cancer survivors.

Effects of screening mammography on the comparative survival rates of African American, white, and Hispanic beneficiaries of a comprehensive health care system

This study reviewed mammographic screening related to breast carcinoma diagnosis and treatment between 1987 and 1997 at Brooke Army Medical Center, San Antonio, TX. Epidemiologic data from the Department of Defense Automated Central Tumor Registry were merged with data from patients' medical records and responses of the patients or their families to a mailed survey. The cases of 907 women grouped by race-white, African American, and Hispanic-were analyzed. Breast carcinoma diagnosed by mammographic screening showed a reversed ratio of early to late stage of cancer occurring for all three groups. That ratio was 1.45 for African Americans, 2.67 for Hispanics, and 3.08 for whites. For those women diagnosed with screening mammography, no statistically significant difference in 5-year survival was found between the races: 86% for whites, 83% for Hispanics, and 80% for African Americans. Mammographic screening as a diagnostic tool appears to equalize survival among whites, Hispanics, and African Americans, in spite of differences in age, stage of diagnosis, and military rank used as a proxy for socioeconomic status. When not controlling for mammographic diagnosis, Kaplan-Meier analysis revealed significant differences in survival patterns between whites, Hispanics, and African Americans. Five-year survival rates were 71% for whites, 74% for Hispanics, and 53% for African Americans. Screening mammography reduced 5-year mortality by almost 59% in African Americans, 52% in whites, and 36% in Hispanics. Whites were diagnosed with breast carcinoma, on average, at 57 years of age-11 years later than African Americans (average age 46 years) and 7 years later than Hispanic women (average age 50 years). As a diagnostic tool, screening mammography was used to discover breast cancer in 36% of white women, 33% of Hispanics, and 22% of African Americans. Further research is recommended to examine the use of mammography among various racial/ethnic groups.

Mammography screening and breast cancer biology in African American women--a review

This review examines some of the key issues in early detection and breast cancer biology for African American (AA) women which contribute to their diagnoses at more advanced stages than white women, and poorer long-term prognoses. While screening mammography is considered an essential factor in eliminating these disparities, its optimal application for AAs is not fully understood. There is a paucity of information on the success with which mammography screening programs are maintained over time in the AA population, and on screening guidelines with regard to age of initiation and frequency. No randomized clinical trials targeting AA women have been reported. This type of information is critical since breast cancer in AA women occurs at younger ages, and frequently demonstrates aggressive tumor biology at diagnosis. Studies are required to determine the incidence of interval cancers in current screening programs, and the influence of the biological characteristics which are known to differ in the breast tumors of AA and white women. Recognition of molecular and cellular characteristics which identify the potential invasiveness of ductal carcinomas in situ is also required. These studies would assist in establishing the criteria for identifying the subpopulation of younger pre-menopausal AA women who would benefit from early initiation of screening. Finally, the epidemiology and biology of mammographic densities, a risk factor for breast cancer and, perhaps, markers of aggressive disease require further study in both AA and white women.

Mammography screening in African American women: evaluating the research

BACKGROUND

Notwithstanding some controversy regarding the benefits of screening mammography, it is generally assumed that the effects are the same for women of all race/ethnic groups. Yet evidence for its efficacy from clinical trial studies comes primarily from the study of white women. It is likely that mammography is equally efficacious in white and African American women when applied under relatively optimal clinical trial conditions, but in actual practice African Americans may not be receiving equal benefit, as reflected in their later stage at diagnosis and greater mortality.

METHODS

Initial searches of Medline using search terms related to screening mammography, race, and other selected topics were supplemented with national data that are routinely published for cancer surveillance. Factors that potentially compromise the benefits of mammography as it is delivered in the current health care system to African American women were examined.

RESULTS

While there have been significant improvements in mammography screening utilization, observational data suggest that African American women may still not be receiving the full benefit. Potential explanatory factors include low use of repeat screening, inadequate followup for abnormal exams, higher prevalence of obesity and, possibly, breast density, and other biologic factors that contribute to younger age at diagnosis.

CONCLUSIONS

Further study of biologic factors that may contribute to limited mammography efficacy and poorer breast cancer outcomes in African American women is needed. In addition, strategies to increase repeat mammography screening and to ensure that women obtain needed followup of abnormal mammograms may increase early detection and improve survival among African Americans. Notwithstanding earlier age at diagnosis for African American women, mammography screening before age 40 years is not recommended, but screening of women aged 40-49 years is particularly critical.

Race, socioeconomic status, and breast carcinoma in the U.S: what have we learned from clinical studies

BACKGROUND

Whether African-American women have biologically more aggressive breast carcinoma compared with white women and whether race acts as a significant independent prognostic factor for survival have not been determined. Alternatively, race merely may be a surrogate for socioeconomic status (SES).

METHODS

A literature review was performed of clinical trials and retrospective studies in the U.S. that compared survival between white women and black women with breast carcinoma after adjustment for known prognostic factors (patient age, disease stage, lymph node status, and estrogen receptor status) to assess the impact of race and SES.

RESULTS

Single institutional and clinical studies suggest that, when black patients are treated appropriately and other prognostic variables are controlled, their survival is similar to the survival of white patients. Twelve retrospective studies and 1 analysis of a clinical trial included SES and race as variables for survival. Only three of those studies revealed race as a significant prognostic factor for survival after adjusting for SES.

CONCLUSIONS

SES replaces race as a predictor of worse outcome after women are diagnosed with breast carcinoma in many studies. However, black women present with more advanced disease that appear more aggressive biologically, and they present at a younger age compared with white women. Further research should be conducted concerning the precise elements of SES that account for the incidence of breast carcinoma, age at diagnosis, hormone receptor status, and survival to devise better strategies to improve outcome.

Can obesity explain the racial difference in stage of breast cancer at diagnosis between black and white women?

OBJECTIVE

Black women are more likely to be diagnosed at a more advanced stage of breast cancer than are white women. Traditionally, this has been attributed in part to social or cultural factors. Given that black women are more likely to be obese than white women and that being obese is associated with a more advanced stage at diagnosis, this study aims to assess to what extent the racial difference in stage at diagnosis can be explained by racial differences in obesity.

METHODS

Incident cases of breast cancer between 1991 and 1997 (white, n = 585; black, n = 381) were identified from hospitals in the Baltimore metropolitan area. Information, including age, race, weight, height, and pathology reports, was obtained from hospital medical records.

RESULTS

Black women were more likely than white women to be diagnosed with breast cancer at tumor-node-metastasis (TNM) stage II or greater (age-adjusted odds ratio [OR] = 1.51, 95% confidence interval [CI] 1.15-1.99). Further, black women were more likely than white women to be overweight or obese. A high body mass index (BMI) was significantly associated with an advanced stage of breast cancer at diagnosis. Adjustment for the higher prevalence of obesity in black women attenuated the risk estimate of more advanced stage of breast cancer at diagnosis in black women compared with white women by approximately 30%.

CONCLUSIONS

Our results suggest that the higher prevalence of obesity among black women plays an important role in explaining their relative disadvantage in stage at diagnosis of breast cancer. Nonetheless, a racial difference in stage of breast cancer at diagnosis persists after adjustment for obesity.

Is obesity a risk factor for prostate cancer, and does it even matter? A hypothesis and different perspective

Measurement of obesity is not as simple as its definition. Currently, several methods of measuring obesity are used in clinical studies. Skinfold thickness, crude weight, lean body mass (LBM), body mass index (BMI), and waist-to-hip ratio (WHR) are some of the more popular methods, but each contains its inherent strengths and flaws. In general, the results of the largest studies on prostate cancer and obesity have not been conclusive. One of the largest studies found an inverse relation to prostate cancer in the youngest age groups. The age and duration of obesity or any rapid changes in weight gain, along with other unhealthy exposures, may have some relation to prostate cancer incidence and mortality. Early intrinsic or extrinsic exposure to estrogen or estrogenlike compounds may provide a protective effect. The timing and duration of a higher estrogen and/or lower testosterone exposure may have a beneficial or detrimental impact on the prognosis of an established prostate tumor. Negative exposures over time such as low levels of sex hormone-binding globulin (SHBG), a greater exposure to growth factors, elevated insulin levels, greater sympathetic activity, higher cholesterol levels, immune system dysfunction, inadequate diets, smoking status, and other factors may be associated with an increased risk of prostate cancer and other diseases. Obesity may also be associated with other cancers for similar and different reasons. For example, morbidity and mortality from postmenopausal breast cancer, colon, kidney, and other cancers are potentially associated with obesity. Other comorbidities such as cataracts, coronary heart disease, diabetes, erectile dysfunction, hypertension, and others are also associated with obesity. The 2 largest prospective studies on BMI and overall mortality have also demonstrated the substantial negative impact of excess weight on society. Prostate cancer risk and obesity need further research to establish if a true association exists, but at this time, does it really matter? Overall, the profound adverse effect of being obese on general health is dramatic, and this is what clinicians and patients need to remember.

Tumor characteristics in African American and white women

BACKGROUND

Previous studies provide evidence that breast cancers occurring in different age and ethnic groups are not evenly distributed with regard to their biologic, pathologic and clinical characteristics. We evaluated the distributions of 11 pathological and biological variables between African-American (AA) and white patients and between three different age groups (20-39, 40-59 and 60-74 years). We examined whether racial differences existed across levels of age.

METHODS

Data were obtained from the Carolina Breast Cancer Study (CBCS), a population-based, case-control study of breast cancer in North Carolina. Eighty hundred and sixty one women with a first diagnosis of invasive breast cancer participated in Phase I of the CBCS. Diagnostic paraffin blocks were obtained from 807 cases. One representative block was scored for histologic type and grade (architectural, nuclear, mitotic and overall). Medical chart review yielded tumor size, lymph node status, distant metastases, stage, hormone receptor status (ER/PR) and DNA ploidy.

RESULTS

Pathologically advanced tumors (large size, high grade, high stage, ER/PR negative) were significantly more common in young and AA women. Racial differences varied by age. Among younger, AAs and whites differed only with respect to ER/PR status, while among older women AAs and whites differed only with respect to stage at diagnosis.

CONCLUSIONS

The results of this study confirm the presence of poorer prognosis breast cancer among AA and younger women. They also highlight the need for age and race to be considered together when evaluating pathologic and biologic characteristics of disease and when making inferences regarding tumor aggressiveness.