Race/ethnicity and breast cancer estrogen receptor status: impact of class, missing data, and modeling assumptions

Social determinants of health inequalities in early phase clinical trials in Northern England

BACKGROUND

Early phase clinical trials in Oncology represent a subspecialised area where UK patient selection is influenced by access to Experimental Cancer Medicine Centres (ECMCs). Equity of access with respect to social determinants of health (SDoH) were explored for two major ECMCs.

METHODS

A retrospective cohort study including all referrals to Newcastle and Manchester ECMCs in 2021 was completed. Consent to screening or pre-screening was stratified against SDoH characteristics, including: Index of Multiple Deprivation (IMD) decile, ethnicity and distance to centre.

RESULTS

1243 patients were referred for trials. IMD quintile 1 (most deprived) patients had reduced likelihood of referral compared to expected population models (OR, 0.67; 95% CI: 0.55 to 0.80, p = <0.0001). IMD quintile 5 (least deprived) had increased likelihood of referral (OR, 1.46; 95% CI: 1.17 to 1.82, p = 0.0007). Living beyond median distance from Manchester reduced the likelihood of consenting to trials (OR, 0.72; 95% CI: 0.55 to 0.94, p = 0.015). Ethnicity data represented a White British propensity.

CONCLUSIONS

Inequalities in socioeconomic and geographic factors influence referral and enrolment to early phase clinical trials in Northern England. This has implications for equity of access and generalisability of trial results internationally and warrants further study.

Patterns of Evidence-Based Care for the Diagnosis, Staging, and First-line Treatment of Breast Cancer by Race-Ethnicity: A SEER-Medicare Study

BACKGROUND

Racial and ethnic disparities in guideline-recommended breast cancer treatment are well documented, however studies including diagnostic and staging procedures necessary to determine treatment indications are lacking. The purpose of this study was to characterize patterns in delivery of evidence-based services for the diagnosis, clinical workup, and first-line treatment of breast cancer by race-ethnicity.

METHODS

SEER-Medicare data were used to identify women diagnosed with invasive breast cancer between 2000 and 2017 at age 66 or older (n = 2,15,605). Evidence-based services included diagnostic procedures (diagnostic mammography and breast biopsy), clinical workup (stage and grade determination, lymph node biopsy, and HR and HER2 status determination), and treatment initiation (surgery, radiation, chemotherapy, hormone therapy, and HER2-targeted therapy). Poisson regression was used to estimate rate ratios (RR) and 95% confidence intervals (CI) for each service.

RESULTS

Black and American Indian/Alaska Native (AIAN) women had significantly lower rates of evidence-based care across the continuum from diagnostics through first-line treatment compared to non-Hispanic White (NHW) women. AIAN women had the lowest rates of HER2-targeted therapy and hormone therapy initiation. While Black women also had lower initiation of HER2-targeted therapy than NHW, differences in hormone therapy were not observed.

CONCLUSIONS

Our findings suggest patterns along the continuum of care from diagnostic procedures to treatment initiation may differ across race-ethnicity groups.

IMPACT

Efforts to improve delivery of guideline-concordant treatment and mitigate racial-ethnic disparities in healthcare and survival should include procedures performed as part of the diagnosis, clinical workup, and staging processes.

Sociodemographic disparities in molecular testing for breast cancer

PURPOSE

Molecular testing is a critical component of breast cancer care used to identify the presence of estrogen and/or progesterone receptors (jointly hormone receptors-HRs) and the expression of human epidermal growth factor 2 (HER2) on a tumor. Our objective was to characterize trends and predictors of lack of molecular testing among female breast cancer patients overall and by sociodemographic characteristics.

METHODS

We examined data on female breast cancer patients diagnosed between 2010 and 2016 from Surveillance Epidemiology and End Results-18. Joinpoint regression analyses assessed annual percent change (APC) in lack of ER, PR, or HER2 testing. Multivariable, multilevel logistic regression models identified factors associated with lack of molecular testing.

RESULTS

A nominally lower proportion of rural patients did not receive molecular testing (e.g., 1.8% in rural vs. 2.3% in urban for HER2). For all tests, a higher proportion of Hispanic and non-Hispanic Black women were not tested. Across all characteristics, improvement in testing was noted, although disparities among groups remained. For example, lack of HER2 testing improved from 3.2 to 1.7% in White patients (APC = - 10.05) but was consistently higher in Black patients 3.9 to 2.3% (APC = - 8.21). Multivariable, multilevel models showed that older, non-Hispanic Black, and unpartnered women were at greater odds of not receiving molecular testing.

CONCLUSIONS

While lack of molecular testing of breast cancer patients is relatively rare, racial/ethnic, insurance status, and age-related disparities have been identified. To reduce testing and downstream treatment and outcome disparities, it is imperative for all breast cancer patients to receive molecular testing.

Learning from missing data: examining nonreporting patterns of height, weight, and BMI among Canadian youth

BACKGROUND

Youth body mass index (BMI), derived from self-reported height and weight, is commonly prone to nonreporting. A considerable proportion of overweight and obesity (OWOB) research relies on such self-report data, however little literature to date has examined this nonreporting and the potential impact on research conclusions. The objective of this study was to examine the characteristics and predictors of missing data in youth BMI, height, and weight.

METHODS

Using a sample of 74,501 Canadian secondary school students who participated in the COMPASS study in 2018/19, sex-stratified generalized linear mixed models were run to examine predictors of missing data while controlling for school-level clustering.

RESULTS

In this sample, 31% of BMI data were missing. A variety of diet, exercise, mental health, and substance use variables were associated with BMI, height, and weight missingness. Perceptions of being overweight (females: 95% CI (1.42,1.62), males: 95% CI (1.71,2.00)) as well as intentions to lose weight (females: 95% CI (1.17,1.33), males: 95% CI (1.13,1.32)) were positively associated with BMI missingness.

CONCLUSIONS

Findings from this study suggest that nonreporting in youth height and weight is likely somewhat related to the values themselves, and hint that social desirability may play a substantial role in nonreporting. The predictors of missingness identified in this study can be used to inform future studies on the potential bias stemming from missing data and identify auxiliary variables that may be used for multiple imputation approaches.

Associations between breast cancer subtype and neighborhood socioeconomic and racial composition among Black and White women

PURPOSE

Studies of Black-White differences in breast cancer subtype often emphasize potential ancestry-associated genetic or lifestyle risk factors without fully considering how the social or economic implications of race in the U.S. may influence risk. We assess whether neighborhood racial composition and/or socioeconomic status are associated with odds of triple-negative breast cancer (TNBC) diagnosis relative to the less-aggressive hormone receptor-positive/HER2-negative subtype (HR+ /HER-), and whether the observed relationships vary across women's race and age groups.

METHODS

We use multilevel generalized estimating equation models to evaluate odds of TNBC vs. HR+ /HER2- subtypes in a population-based cohort of 7291 Black and 74,208 White women diagnosed with breast cancer from 2006 to 2014. Final models include both neighborhood-level variables, adjusting for individual demographics and tumor characteristics.

RESULTS

Relative to the HR+ /HER- subtype, we found modestly lower odds of TNBC subtype among White women with higher neighborhood median household income (statistically significant within the 45-64 age group, OR = 0.981 per $10,000 increase). Among Black women, both higher neighborhood income and higher percentages of Black neighborhood residents were associated with lower odds of TNBC relative to HR+ /HER2-. The largest reduction was observed among Black women diagnosed at age ≥ 65 (OR = 0.938 per $10,000 increase; OR = 0.942 per 10% increase in Black residents).

CONCLUSION

The relationships between neighborhood composition, neighborhood socioeconomic status, and odds of TNBC differ by race and age. Racially patterned social factors warrant further exploration in breast cancer subtype disparities research.

Breast Cancer Estrogen Receptor Status According to Biological Generation: US Black and White Women Born 1915-1979

Evidence suggests that contemporary population distributions of estrogen-receptor (ER) status among breast cancer patients may be shaped by earlier major societal events, such as the 1965 abolition of legal racial discrimination in the United States (state and local "Jim Crow" laws) and the Great Famine in China (1959-1961). We analyzed changes in ER status in relation to Jim Crow birthplace among the 46,417 black and 339,830 white US-born, non-Hispanic women in the Surveillance, Epidemiology, and End Results (SEER) 13 Registry Group who were born between 1915 and 1979 and diagnosed (ages 25-84 years, inclusive) during 1992-2012. We grouped the cases according to birth cohort and quantified the rate of change using the haldane (which scales change in relation to biological generation). The percentage of ER-positive cases rose according to birth cohort (1915-1919 to 1975-1979) only among women diagnosed before age 55. Changes according to biological generation were greater among black women than among white women, and among black women, they were greatest among those born in Jim Crow (versus non-Jim Crow) states, with this group being the only group to exhibit high haldane values (>|0.3|, indicating high rate of change). Our study's analytical approach and findings underscore the need to consider history and societal context when analyzing ER status among breast cancer patients and racial/ethnic inequities in its distribution.

Tumor Specimen Biobanks: Data Gaps for Analyzing Health Inequities-the Case of Breast Cancer

Biobanks are increasingly recognized to be vital for analyzing tumor properties, treatment options, and clinical prognosis, yet few data exist on whether they are equipped to enable research on cancer inequities, that is, unfair and unnecessary social group differences in health. We conducted a systematic search of global biobanks, identified 46 that have breast tumor tissue and share data externally with academic researchers, and e-mailed and called to obtain data on the sociodemographic, socioeconomic, and geospatial data included, plus time span encompassed. Among the 32 biobank respondents, 91% housed specimens solely from the Global North, only 31% obtained socioeconomic data, 63% included racial/ethnic data (of which 55% lacked socioeconomic data), 44% included limited geographic data, and 55% had specimens dating back at most to 2000. To enable research to address cancer inequities, including trends over time, biobanks will need to address the data gaps documented by our study.

Does the association between early life growth and later obesity differ by race/ethnicity or socioeconomic status? A systematic review

PURPOSE

Rapid growth during infancy predicts higher risk of obesity later in childhood. The association between patterns of early life growth and later obesity may differ by race/ethnicity or socioeconomic status (SES), but prior evidence syntheses do not consider vulnerable subpopulations.

METHODS

We systemically reviewed published studies that explored patterns of early life growth (0-24 months of age) as predictors of later obesity (>24 months) that were either conducted in racial/ethnic minority or low-SES study populations or assessed effect modification of this association by race/ethnicity or SES. Literature searches were conducted in PubMed and SocINDEX.

RESULTS

Ten studies met the inclusion criteria. Faster growth during the first 2 years of life was consistently associated with later obesity irrespective of definition and timing of exposure and outcome measures. Associations were strongest in populations composed of greater proportions of racial/ethnic minority and/or low-SES children. For example, ORs ranged from 1.17 (95% CI: 1.11, 1.24) in a heterogeneous population to 9.24 (95% CI: 3.73, 22.9) in an entirely low-SES nonwhite population.

CONCLUSIONS

The impact of rapid growth in infancy on later obesity may differ by social stratification factors such as race/ethnicity and family income. More robust and inclusive studies examining these associations are needed.

Jim Crow and estrogen-receptor-negative breast cancer: US-born black and white non-Hispanic women, 1992-2012

PURPOSE

It is unknown whether Jim Crow-i.e., legal racial discrimination practiced by 21 US states and the District of Columbia and outlawed by the US Civil Rights Act in 1964-affects US cancer outcomes. We hypothesized that Jim Crow birthplace would be associated with higher risk of estrogen-receptor-negative (ER-) breast tumors among US black, but not white, women and also a higher black versus white risk for ER- tumors.

METHODS

We analyzed data from the SEER 13 registry group (excluding Alaska) for 47,157 US-born black non-Hispanic and 348,514 US-born white non-Hispanic women, aged 25-84 inclusive, diagnosed with primary invasive breast cancer between 1 January 1992 and 31 December 2012.

RESULTS

Jim Crow birthplace was associated with increased odds of ER- breast cancer only among the black, not white women, with the effect strongest for women born before 1965. Among black women, the odds ratio (OR) for an ER- tumor, comparing women born in a Jim Crow versus not Jim Crow state, equaled 1.09 (95% confidence interval [CI] 1.06, 1.13), on par with the OR comparing women in the worst versus best census tract socioeconomic quintiles (1.15; 95% CI 1.07, 1.23). The black versus white OR for ER- was higher among women born in Jim Crow versus non-Jim Crow states (1.41 [95% CI 1.13, 1.46] vs. 1.27 [95% CI 1.24, 1.31]).

CONCLUSIONS

The unique Jim Crow effect for US black women for breast cancer ER status underscores why analysis of racial/ethnic inequities must be historically contextualized.

Imputing estrogen receptor (ER) status in a population-based cancer registry: a sensitivity analysis

Breast cancers are clinically heterogeneous based on tumor markers. The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program provides baseline data on these tumor markers for reporting cancer burden and trends over time in the US general population. These tumor markers, however, are often prone to missing observations. In particular, estrogen receptor (ER) status, a key biomarker in the study of breast cancer, has been collected since 1992 but historically was not well-reported, with missingness rates as high as 25% in early years. Previous methods used to correct estimates of breast cancer incidence or ER-related odds or prevalence ratios for unknown ER status have relied on a missing-at-random (MAR) assumption. In this paper, we explore the sensitivity of these key estimates to departures from MAR. We develop a predictive mean matching procedure that can be used to multiply impute missing ER status under either an MAR or a missing not at random assumption and apply it to the SEER breast cancer data (1992-2012). The imputation procedure uses the predictive power of the rich set of covariates available in the SEER registry while also allowing us to investigate the impact of departures from MAR. We find some differences in inference under the two assumptions, although the magnitude of differences tends to be small. For the types of analyses typically of primary interest, we recommend imputing SEER breast cancer biomarkers under an MAR assumption, given the small apparent differences under MAR and missing not at random assumptions. Copyright © 2016 John Wiley & Sons, Ltd.

Metrics for monitoring cancer inequities: residential segregation, the Index of Concentration at the Extremes (ICE), and breast cancer estrogen receptor status (USA, 1992-2012)

PURPOSE

To address the paucity of evidence on residential segregation and cancer, we explored their relationship using a new metric: the Index of Concentration at the Extremes (ICE). We focused on breast cancer estrogen receptor (ER) status, a biomarker associated with survival and, etiologically, with social and economic privilege.

METHODS

We obtained data from the 13 registry group of US Surveillance, Epidemiology, and End Results (SEER) program for 1992-2012 on all women aged 25-84 who were diagnosed with primary invasive breast cancer (n = 516,382). We appended to each case's record her annual county median household income quintile and the quintile for her annual county value for ICE measures for income (≤20th vs. ≥80th household income quintile), race/ethnicity (black vs. white), and income plus race/ethnicity (low-income black vs. high-income white). The odds of being ER+ versus ER- were estimated in relation to the county-level income and ICE measures, adjusting for relevant covariates.

RESULTS

Women in the most privileged versus deprived county quintile for household income and for all three ICE measures had a 1.1- to 1.3-fold increased odds (95 % confidence intervals excluding 1) of having an ER+ tumor. These results were robust to adjustment for age at diagnosis, cancer registry, tumor characteristics (tumor stage, size, histology, grade), and race/ethnicity.

CONCLUSION

A focus on segregation offers news possibilities for understanding how inequitable group relations contribute to cancer inequities. The utility of employing the ICE for monitoring cancer inequities should be investigated in relation to other cancer outcomes.

How Does Managed Care Improve the Quality of Breast Cancer Care Among Medicare-Insured Minority Women?

PURPOSE

The aim of this study is to investigate if evidence-based clinical guidelines are implemented equitability among ethnic minority breast cancer patients using Medicare Advantage and investigate if presumed advantages of managed care over fee-for-service are greater for minorities than for Whites.

METHODS

Data from the Surveillance, Epidemiology, and End Results and Medicare were used to examine 70,755 women over age 65 diagnosed with early stage breast cancer between 2005 and 2009. Implementation of two clinical guidelines was assessed: receipt of radiation therapy after breast conserving surgery and estrogen receptor status documentation. Multilevel logistic regression and inverse propensity weighting controlled for confounding.

RESULTS

African Americans are still less likely than Whites to receive radiation therapy after breast-conserving surgery, whether they use Medicare fee-for-service (OR 95 % CI) = 0.90 (0.83, 0.98) or managed care (OR 95 % CI) = 0.87 (0.76, 1.00). Differences between receipt of radiation therapy by insurance plan type was nonexistent. Relative to FFS, the use of managed care improved the odds of having estrogen receptor status documented by 44 % in African Americans, (OR 95 % CI) = 1.44 (1.15, 1.83) and by 42 % in Latina patients (OR 95 % CI) = 1.42 (1.17, 1.78).

CONCLUSIONS

Compared to Medicare fee-for-service, ethnic and racial disparities among Medicare Advantage users were reduced. We observed fewer disparities, but not an elimination of disparities, among Medicare Advantage enrollees receiving breast cancer care with an organizational and patient component of care. This suggests managed care may still need to focus on minority patient empowerment and involvement in care.

The Effect of Socio-Economic-Cultural Factors on Breast Cancer

OBJECTIVE

Socioeconomic and cultural factors influence breast cancer prognosis. The effect of these factors on breast cancer was evaluated among women who live in Gaziantep and its surroundings.

MATERIALS AND METHODS

female patients who were admitted to Gaziantep University Oncology Hospital with a diagnosis of breast cancer between October 2006-July 2013 were included in the study. The effects of socio-demographic characteristics on clinical-pathological features were evaluated.

RESULTS

The mean age of 813 women was 48.8 years. The majority were premenopausal women. Advanced stage disease on diagnosis was detected more in our region. The rate of breast cancer with unfavorable prognostic features was higher among patients who were illiterate, with low economic income and residing in rural areas.

CONCLUSION

Socioeconomic-cultural factors influence the biology and clinical course of breast cancer among women who live in Gaziantep province.

US breast cancer mortality trends in young women according to race

BACKGROUND

Young age at diagnosis has a negative prognostic impact on outcome in patients with breast cancer (BC). In the current study, the authors sought to determine whether there is a differential effect of race and examined mortality trends according to race and age.

METHODS

The Surveillance, Epidemiology, and End Results program was used to identify women aged <50 years with invasive BC diagnosed between 1990 and 2009. Multivariate regression analyses were performed to determine the risk-adjusted likelihood of survival for white and black patients. Annual hazards of BC death according to race and calendar period and adjusted relative hazards of death for white and black women stratified by age were computed.

RESULTS

A total of 162,976 women were identified, 126,573 of whom were white, 20,405 of whom were black, and 15,998 of whom were of other races. At a median follow-up of 85 months, the 5-year disease specific survival rates were 90.1% for white patients and 79.3% for black patients. Annual hazards of death in white patients decreased by 26% at 5 years after diagnosis in contrast to the hazards in black patients, which decreased by only 19%. With 1990 as the referent year, the adjusted relative hazards of death in women aged <40 years in 2005 were 0.55 (95% confidence interval [95% CI], 0.46-0.66) and 0.68 (95% CI, 0.49-0.93), respectively, for white and black women. In women aged 40 to 49 years, adjusted hazards of death were 0.53 (95% CI, 0.47-0.60) and 0.78 (95% CI, 0.61-0.99), respectively, for white and black women.

CONCLUSIONS

Among young women diagnosed with BC, black patients have a worse outcome compared with white patients. Mortality declines have been observed over time in both groups, although more rapid gains have been reported to occur in white women. Emphasis should be placed on improving outcomes for young patients with BC.

Breast cancer pathology, receptor status, and patterns of metastasis in a rural appalachian population

Breast cancer patients in rural Appalachia have a high prevalence of obesity and poverty, together with more triple-negative phenotypes. We reviewed clinical records for tumor receptor status and time to distant metastasis. Body mass index, tumor size, grade, nodal status, and receptor status were related to metastatic patterns. For 687 patients, 13.8% developed metastases to bone (n = 42) or visceral sites (n = 53). Metastases to viscera occurred within five years, a latent period which was shorter than that for bone (P = 0.042). More women with visceral metastasis presented with grade 3 tumors compared with the bone and nonmetastatic groups (P = 0.0002). There were 135/574 women (23.5%) with triple-negative breast cancer, who presented with lymph node involvement and visceral metastases (68.2% versus 24.3%; P = 0.033). Triple-negative tumors that metastasized to visceral sites were larger (P = 0.007). Developing a visceral metastasis within 10 years was higher among women with triple-negative tumors. Across all breast cancer receptor subtypes, the probability of remaining distant metastasis-free was greater for brain and liver than for lung. The excess risk of metastatic spread to visceral organs in triple-negative breast cancers, even in the absence of positive nodes, was combined with the burden of larger and more advanced tumors.

Variants of estrogen-related genes and breast cancer risk in European and African American women

It has been observed previously that compared with women of European ancestry (EA), those of African ancestry (AA) are more likely to develop estrogen receptor (ER)-negative breast cancer, although the mechanisms have not been elucidated. We tested the associations between breast cancer risk and a targeted set of 20 genes known to be involved in estrogen synthesis, metabolism, and response and potential gene-environment interactions using data and samples from 1307 EA (658 cases) and 1365 AA (621 cases) participants from the Women's Circle of Health Study (WCHS). Multivariable logistic regression found evidence of associations with single-nucleotide polymorphisms (SNPs) in the ESR1 gene in EA women (rs1801132, odds ratio (OR)=1.47, 95% CI=1.20-1.80, P=0.0002; rs2046210, OR=1.24, 95% CI=1.04-1.47, P=0.02; and rs3020314, OR=1.43, 95% CI=1.19-1.70, P=0.00009), but not in AA women. The only other gene associated with breast cancer risk was CYP1A2 in AA women (rs2470893, OR=1.42, 95% CI=1.00-2.02, P=0.05), but not in EA women. When stratified by ER status, ESR1 rs1801132, rs2046210, and rs3020314 showed stronger associations in ER-positive than in ER-negative breast cancer in only EA women. Associations with the ESR1 SNPs in EA women also appeared to be stronger with longer endogenous estrogen exposure or hormonal replacement therapy use. Our results indicate that there may be differential genetic influences on breast cancer risk in EA compared with AA women and that these differences may be modified by tumor subtype and estrogen exposures. Future studies with a larger sample size may determine the full contribution of estrogen-related genes to racial/ethnic differences in breast cancer.

Association between chronological change of reproductive factors and breast cancer risk defined by hormone receptor status: results from the Seoul Breast Cancer Study

Lifestyle factors have been chronologically changed into western style ones, which could result in the rapid increase of breast cancer incidence in Korea. It is plausible that reproductive factors through hormonal mechanisms are differentially related to the risk of breast cancer subtypes. We investigated the association of reproductive risk factors on breast cancer by birth year groups and also evaluated the differential associations on the hormone receptor-defined subtypes. Using the data from the Seoul Breast Cancer Study (SeBCS), a multicenter case-control study, 3,332 breast cancer patients and 3,620 control subjects were analyzed. The distribution of subtypes among cases was as follows: 61.0 % estrogen receptor (ER)-positive, 51.9 % progesterone receptor (PR)-positive, and 43.4 % both ER/PR-positive status, respectively. Polytomous logistic regression and Wald tests for heterogeneity have been used across the subtypes. The frequencies of reproductive-related risk factors including early age at menarche, nulligravid, age at first full-term pregnancy (FFTP), duration of estrogen exposure before FFTP (EEBF), less number of children, never breastfeeding, and short duration of breastfeeding has increased as women were born later in both cases and controls, respectively (p trend < 0.0001. Among breast cancer patients, either ER- or PR-positive subtypes were increased in women born in 1960s compared to women born in 1940s. Early age at menarche increased the risk of breast cancer regardless of the subtypes while nulligravid, late age at FFTP, and longer duration of EEBP were associated with hormone receptor-positive cancer risk only (p heterogeneity < 0.05), which associations were stronger among women born later. Our results suggest that the associations of age at menarche, parity, age at FFTP, and duration of EEBF with breast cancer risk were different based on the hormone receptor status and birth year groups in Korea.

Population and target considerations for triple-negative breast cancer clinical trials

Triple-negative breast cancer (TNBC) is an aggressive disease subtype that has a poor prognosis. Extensive epidemiological evidence demonstrates clear socioeconomic and demographic associations with increased likelihood of TNBC in both poorer and minority populations. Thus, biological aggressiveness with few known therapeutic directions generates disparities in breast cancer outcomes for vulnerable populations. Emerging molecular evidence of potential targets in triple-negative subpopulations offers great potential for future clinical trial directions. However, trials must appropriately consider populations at risk for aggressive subtypes of disease in order to address this disparity most completely. New US FDA draft guidance documents provide both flexible outcomes for accelerated approvals as well as flexibility in design with adaptive trials. Careful planning with design, potential patient population and choices of molecular targets informed by biomarkers will be critical to address TNBC clinical care.

Effect of patient socioeconomic status on access to early-phase cancer trials

PURPOSE

Little is known about the influence of socioeconomic factors on patient access to cancer trials. Differences should be considered to ensure generalizability of trial results and equality of access.

METHODS

Phase I trials unit referrals at our center over 5 years, from 2007 to 2012, were reviewed. Socioeconomic status was defined by the Index of Multiple Deprivation (IMD; 1, least deprived; 5, most deprived). Multivariate analysis was performed comparing incident cancer cases with referred patients and those ultimately enrolled onto a trial.

RESULTS

Four hundred thirty patients were referred (median age, 62 years). Compared with 10,784 incident cases, referral was less likely for patients in the more-deprived quintiles compared with the least deprived (IMD 5: odds ratio [OR], 0.53; 95% CI, 0.38 to 0.74). Once reviewed in the unit, enrollment onto a trial was not affected (IMD 5: OR, 0.81; 95% CI, 0.40 to 1.63). Ethnicity analysis showed the nonwhite population was less likely to be recruited (OR, 0.48; 95% CI, 0.26 to 0.88). This relationship was lost with adjustment for age, sex, cancer type, and deprivation index.

CONCLUSION

We show for the first time to our knowledge that socioeconomic status affects early-phase cancer trial referrals. The least-deprived patients are almost twice as likely to be referred compared with the most deprived. This may be because more-deprived patients are less suitable for a trial-as a result of comorbidities, for example-or because of inequalities that could be addressed by patient or referrer education. Once reviewed at the unit, enrollment onto a trial is not affected by deprivation.

Mind the gap: racial differences in breast cancer incidence and biologic phenotype, but not stage, among low-income women participating in a government-funded screening program

Breast cancer mortality rates in South Carolina (SC) are 40 % higher among African-American (AA) than European-American (EA) women. Proposed reasons include race-associated variations in care and/or tumor characteristics, which may be subject to income effects. We evaluated race-associated differences in tumor biologic phenotype and stage among low-income participants in a government-funded screening program. Best Chance Network (BCN) data were linked with the SC Central Cancer Registry. Characteristics of breast cancers diagnosed in BCN participants aged 47-64 years during 1996-2006 were abstracted. Race-specific case proportions and incidence rates based on estrogen receptor (ER) status and histologic grade were estimated. Among 33,880 low-income women accessing BCN services, repeat breast cancer screening utilization was poor, especially among EAs. Proportionally, stage at diagnosis did not differ by race (607 cancers, 53 % among AAs), with about 40 % advanced stage. Compared to EAs, invasive tumors in AAs were 67 % more likely (proportions) to be of poor-prognosis phenotype (both ER-negative and high-grade); this was more a result of the 46 % lesser AA incidence (rates) of better-prognosis (ER+ lower-grade) cancer than the 32 % greater incidence of poor-prognosis disease (p values <0.01). When compared to the general SC population, racial disparities in poor-prognostic features within the BCN population were attenuated; this was due to more frequent adverse tumor features in EAs rather than improvements for AAs. Among low-income women in SC, closing the breast cancer racial and income mortality gaps will require improved early diagnosis, addressing causes of racial differences in tumor biology, and improved care for cancers of poor-prognosis biology.

Use of imputed population-based cancer registry data as a method of accounting for missing information: application to estrogen receptor status for breast cancer

The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program provides a rich source of data stratified according to tumor biomarkers that play an important role in cancer surveillance research. These data are useful for analyzing trends in cancer incidence and survival. These tumor markers, however, are often prone to missing observations. To address the problem of missing data, the authors employed sequential regression multivariate imputation for breast cancer variables, with a particular focus on estrogen receptor status, using data from 13 SEER registries covering the period 1992-2007. In this paper, they present an approach to accounting for missing information through the creation of imputed data sets that can be analyzed using existing software (e.g., SEER*Stat) developed for analyzing cancer registry data. Bias in age-adjusted trends in female breast cancer incidence is shown graphically before and after imputation of estrogen receptor status, stratified by age and race. The imputed data set will be made available in SEER*Stat (http://seer.cancer.gov/analysis/index.html) to facilitate accurate estimation of breast cancer incidence trends. To ensure that the imputed data set is used correctly, the authors provide detailed, step-by-step instructions for conducting analyses. This is the first time that a nationally representative, population-based cancer registry data set has been imputed and made available to researchers for conducting a variety of analyses of breast cancer incidence trends.

Socioeconomic disparities and breast cancer hormone receptor status

PURPOSE

Recent research, although inconsistent, indicates that socioeconomic status (SES) may be associated with hormone receptor (HR) status. This study aims to examine the association between SES and breast cancer HR status within and across racial/ethnic groups stratified by age at diagnosis and tumor stage.

METHODS

The study subjects were 184,602 women with incident breast cancer diagnosed during 2004-2007 and identified from the National Cancer Institute's Surveillance, Epidemiology and End Results program. Log-binomial regression assessed the risk of having breast tumors that were (1) HR-negative versus HR-positive and (2) HR-unknown versus HR-known between women who, at the time of diagnosis, were residing in high or medium poverty areas compared to low poverty areas.

RESULTS

High poverty areas tended to have a greater prevalence of HR-negative tumors compared to more affluent areas. Although not always significant, this was observed among non-Hispanic white and Hispanic women regardless of age-tumor stage category, and only among young, non-Hispanic black women and non-Hispanic Asian/Pacific Islander women with regional and distant stage. High poverty areas also tended to have a greater prevalence of HR-unknown tumors compared to more affluent areas. Furthermore, significant trends between HR status and poverty level varied by race/ethnicity, age, and tumor stage.

CONCLUSIONS

Poverty may be related to breast cancer negative and unknown HR status. These findings suggest the effects of non-genetic factors on biochemical features of breast cancer, as well as imply a clinical importance to improve HR measurement or recording for low socioeconomic breast cancer patients.

Kindergarten stressors and cumulative adrenocortical activation: the "first straws" of allostatic load?

Using an ethnically diverse longitudinal sample of 338 kindergarten children, this study examined the effects of cumulative contextual stressors on children's developing hypothalamic-pituitary-adrenocortical (HPA) axis regulation as an early life indicator of allostatic load. Chronic HPA axis regulation was assessed using cumulative, multiday measures of cortisol in both the fall and spring seasons of the kindergarten year. Hierarchical linear regression analyses revealed that contextual stressors related to ethnic minority status, socioeconomic status, and family adversity each uniquely predicted children's daily HPA activity and that some of those associations were curvilinear in conformation. Results showed that the quadratic, U-shaped influences of family socioeconomic status and family adversity operate in different directions to predict children's HPA axis regulation. Results further suggested that these associations differ for White and ethnic minority children. In total, this study revealed that early childhood experiences contribute to shifts in one of the principal neurobiological systems thought to generate allostatic load, confirming the importance of early prevention and intervention efforts. Moreover, findings suggested that analyses of allostatic load and developmental theories accounting for its accrual would benefit from an inclusion of curvilinear associations in tested predictive models.

Investigating reasons for ethnic inequalities in breast cancer survival in New Zealand

OBJECTIVE

This study investigated the role that demographic and tumour factors play in explaining ethnic inequalities in breast cancer survival.

DESIGN

Breast cancer cases notified to the New Zealand Cancer Registry (NZCR) from April 2005 to April 2007 were followed up to April 2009. Māori, Pacific and non-Māori/non-Pacific women were categorised according to ethnicity on the NZCR. Deprivation was analysed as quintiles of the New Zealand area-based index of socio-economic position. Relative survival rates were estimated using ethnic-specific life tables. Missing values were imputed and excess mortality modelling was used to estimate the contribution of demographic and tumour factors to ethnic inequalities in survival.

RESULTS

There were 2968 breast cancer cases (76.5% non-Māori/non-Pacific, 17% Māori, and 6.5% Pacific) included and 433 recorded deaths. Relative survival rates at 4 years were 91.5% (95% confidence interval (CI) 89.7 to 92.9) for non-Māori/non-Pacific, 86.2% (CI 80.3 to 90.4) for Māori, and 79.6% (CI 68.2 to 87.2) for Pacific women. Using non-Māori/non-Pacific as the reference group, the age-adjusted hazard ratio (HR) dropped for Māori from 1.76 (CI 1.22 to 2.48) to 1.43 (CI 0.97 to 2.10) when further adjusted by deprivation. For Pacific the HR dropped from 2.49 (CI 1.57 to 3.94) to 1.94 (CI 1.20 to 3.13). Inequalities persisted after adjustment for subtype variables (ER/PR/HER2), but adjusting for access to care variables (extent/size) eliminated the ethnic inequalities in excess mortality.

CONCLUSION

Ethnic disparities in breast cancer survival in New Zealand can be attributed to deprivation and differential access to health care rather than differences in breast cancer subtypes.

The enduring and evolving relationship between social class and breast cancer burden: a review of the literature

INTRODUCTION

Breast cancer in women has historically been seen as a "cancer of affluence" and there is a well-documented higher incidence among women of higher social class, as well as in societies with higher resources. However, the relationship between social class and breast cancer disease characteristics, especially those associated with poorer prognosis, is less well documented, and the overall relationship between breast cancer mortality and social class has been shown to vary. Furthermore, rapid changes in women's health and health-related behaviors in societies around the world may have an impact on both incidence and mortality patterns for breast cancer in the future.

METHODS

A PUBMED search on breast cancer and social class (incorporating the MeSH-nested concept of SES) yielded 403 possible studies published between 1978 and 2009, of which 90 met criteria for review. Our review discusses conceptualization and measurement of women's social class in each study, as well as findings related to breast cancer incidence, tumor biology or mortality, associated with social class.

FINDINGS

We found mostly consistent evidence that breast cancer incidence continues to be higher in higher social class groups, with some modification of risk with adjustment for known risk factors, including physical activity and reproductive history. However, biologic characteristics associated with poorer prognosis were negatively associated with social class (i.e., greater occurrence among disadvantaged women), and mortality from breast cancer showed inconsistent relationship to social class.

CONCLUSIONS

We discuss these studies in relation to the growing burden of breast cancer among low resource groups and countries, and the need for cancer control strategies reflecting the emerging demographics of breast cancer risk.

Temporal trends in the black/white breast cancer case ratio for estrogen receptor status: disparities are historically contingent, not innate

OBJECTIVE

For at least three decades, many investigators have reported on the US black/white breast cancer case ratio for estrogen receptor (ER) status as if it reflected an intrinsic biological difference. In light of racial/ethnic differences in declines in the incidence of ER+ breast cancer, as linked to changing use of hormone therapy, we empirically tested whether the black/white breast cancer estrogen receptor ratio has changed over time.

METHODS

We examined temporal trends in the odds of being ER+ among white as compared to black women among all cases of invasive breast cancer occurring among women residing in the catchment area of the SEER 13 Registries Database between 1992 and 2005.

RESULTS

During the study period, the odds of being ER+ among the white compared to black cases increased from 1992 to 2002 (a statistically significant joinpoint; p < 0.05; peak odds ratio (2002) = 2.25 (95% confidence interval 2.13, 2.39)). Thereafter, the odds ratio leveled off (post-2002 slope not significantly different from zero; p = 0.326). Among women aged 45-54, moreover, the post-2002 decline tended toward statistical significance (p = 0.0891).

CONCLUSIONS

The results suggest the black/white breast cancer case estrogen receptor ratio is historically contingent, not innate.

Ethnic and socioeconomic trends in breast cancer incidence in New Zealand

BACKGROUND

Breast cancer incidence varies between social groups, but differences have not been thoroughly examined in New Zealand. The objectives of this study are to determine whether trends in breast cancer incidence varied by ethnicity and socioeconomic position between 1981 and 2004 in New Zealand, and to assess possible risk factor explanations.

METHODS

Five cohorts of the entire New Zealand population for 1981-86, 1986-1991, 1991-1996, 1996-2001, and 2001-2004 were created, and probabilistically linked to cancer registry records, allowing direct determination of ethnic and socioeconomic trends in breast cancer incidence.

RESULTS

Breast cancer rates increased across all ethnic and socioeconomic groups between 1981 and 2004. Māori women consistently had the highest age standardised rates, and the difference between Māori and European/Other women increased from 7% in 1981-6 to 24% in 2001-4. Pacific and Asian women had consistently lower rates of breast cancer than European/Other women over the time period studied (12% and 28% lower respectively when pooled over time), although young Pacific women had slightly higher incidence rates than young European/other women. A gradient between high and low income women was evident, with high income women having breast cancer rates approximately 10% higher and this difference did not change significantly over time.

CONCLUSIONS

Differences in breast cancer incidence between European and Pacific women and between socioeconomic groups are explicable in terms of known risk factors. However no straightforward explanation for the relatively high incidence amongst Māori is apparent. Further research to explore high Māori breast cancer rates may contribute to reducing the burden of breast cancer amongst Māori women, as well as improving our understanding of the aetiology of breast cancer.

The association of race/ethnicity, insurance status, and socioeconomic factors with breast cancer care

BACKGROUND

Few data are available on how race/ethnicity, insurance, and socioeconomic status (SES) interrelate to influence breast cancer treatment. The authors examined care for a national cohort of breast cancer patients to assess whether insurance and SES were associated with racial/ethnic differences in care.

METHODS

The authors used multivariate logistic regression to assess the probability of definitive locoregional therapy, hormone receptor testing, and adjuvant systemic therapy among 662,117 white, black, and Hispanic women diagnosed with invasive breast cancer during 1998-2005 at National Cancer Data Base hospitals. In additional models, the authors included insurance and area-level SES to determine whether these variables were associated with observed racial/ethnic disparities.

RESULTS

Most women were white (86%), 10% were black, and 4% were Hispanic. Most had private insurance (51%) or Medicare (41%). Among eligible patients, 80.0% (stage I/II) had definitive locoregional therapy, 98.5% (stage I-IV) had hormone receptor testing, and 53.1% and 50.2% (stage I-III) received adjuvant hormonal therapy and chemotherapy, respectively. After adjustment, black (vs white) women had less definitive locoregional therapy (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.88-0.94), hormonal therapy (OR, 0.90; 95% CI, 0.87-0.93), and chemotherapy (OR, 0.87; 95% CI, 0.84-0.91). Hispanic (vs white) women were also less likely to receive hormonal therapy. Hormone receptor testing did not differ by race/ethnicity. Racial disparities persisted despite adjusting for insurance and SES.

CONCLUSIONS

The modest association between black (vs white) race and guideline-recommended breast cancer care was insensitive to adjustment for insurance and area-level SES. Further study is required to better understand disparities and to ensure receipt of care.

Investigating reasons for socioeconomic inequalities in breast cancer survival in New Zealand

BACKGROUND

This study investigated the role that demographic and tumour factors play in explaining socioeconomic inequalities in breast cancer survival.

METHODS

Breast cancer cases notified to the New Zealand Cancer Registry (NZCR) from April 2005 to April 2007 were followed up to April 2009. The New Zealand area-based deprivation index (NZDep) was used as a measure of socioeconomic position. Relative survival rates were estimated using sex-, deprivation- and ethnic-specific life tables. Multiple imputation was used to impute missing data. Excess mortality modelling was used to estimate the contribution of demographic and tumour factors to inequalities in survival.

RESULTS

There were 2968 breast cancer cases included and 433 recorded deaths. Relative survival rates at 4 years varied across deprivation groups. Using NZDep deciles 1-4 (least deprived) as the reference group, the age- and ethnicity-adjusted hazard ratio (HR) for NZDep deciles 7-8 was 2.03 (CI 1.36-3.04) and for NZDep deciles 9-10 was 1.93 (CI 1.28-2.92). In the fully adjusted model there remained 50% excess mortality for the two most deprived groups compared to the most affluent. Variables which measured timely access to care (extent/size) accounted for more of the survival disparity than breast cancer subtype variables (ER/PR/HER2).

CONCLUSION

Women from deprived areas in New Zealand who are diagnosed with breast cancer are less likely to survive as long as those from affluent areas. A substantial proportion of these socioeconomic disparities can be attributed to differential access to health care although other factors, currently unknown, are also likely to play an important role.

Decline in US breast cancer rates after the Women's Health Initiative: socioeconomic and racial/ethnic differentials

OBJECTIVES

We investigated whether there were socioeconomic and racial/ethnic disparities in recent reported declines in overall US breast cancer incidence rates attributed to post-2002 declines in hormone therapy use following publication of the Women's Health Initiative study.

METHODS

We analyzed 1992-2005 US breast cancer incidence data from the US Surveillance, Epidemiology and End Result (SEER) 13 Registries Database, stratified by race/ethnicity, county income level, age, and estrogen receptor (ER) status.

RESULTS

As we hypothesized, between 1992 and 2005, the temporal pattern of rising and then falling US breast cancer incidence rates occurred only among White non-Hispanic women who lived in high-income counties, were aged 50 years and older, and had ER-positive tumors. No such trends were evident--regardless of county income level, ER status, or age--among Black non-Hispanic, Asian/Pacific Islander, Hispanic, or-where numbers were sufficient to conduct meaningful analyses-American Indian/Alaska Native women.

CONCLUSIONS

The recent decline in US breast cancer incidence was not equally beneficial to all women, but instead mirrored the social patterning of hormone therapy use. Joint information on socioeconomic resources and race/ethnicity is vital for correctly understanding disease distribution, including that of breast cancer.

Racial differences in the incidence of breast cancer subtypes defined by combined histologic grade and hormone receptor status

Breast cancer encompasses several distinct clinical entities of very different characteristics and behaviors, a fact which likely contributes to the higher breast cancer mortality in African-Americans (AA) despite the higher incidence in European-Americans (EA). We are interested in how incidence variability in cancer subtypes defined by combined estrogen receptor (ER) and grade contributes to racial mortality disparities. As an initial step, we compared age-specific and age-adjusted incidence rates for each ER/Grade subtype in South Carolina (SC-a southern state) with Ohio (a northern mid-western state), using state registry data for 1996-2004. Each ER/Grade subtype had a distinct incidence pattern and rate, with three striking racial/geographic differences. First, the racial incidence disparity in ER negative (ER-) cancers was mostly within the ER-/G3 subtype, of which AAs had ~65% higher incidence than did EAs; ER-/G2 was much less common, but of significantly higher incidence in AAs. Second, the racial disparity in ER positive (ER+) cancers was in the ER+/lower-grade cancers, with a marked EA excess in both states. Third, AA incidence of the ER+/lower-grade subtypes was ~26% higher in Ohio than in SC. The other subtypes (ER-/G1 and ER+/G3) varied minimally by race and state, and the latter showed a strong association with age. Age adjustment halved the racial difference in mean age at diagnosis to about 2 years younger in AAs, compared to 4 years younger in case comparisons. Use of age-adjusted and age-specific rates of breast cancer subtypes may improve understanding of racial incidence and mortality disparities over time and geography. This approach also may aid in estimating the race-specific incidence rates of triple-negative breast cancer.

Association between neighborhood safety and overweight status among urban adolescents

Background

Neighborhood safety may be an important social environmental determinant of overweight. We examined the relationship between perceived neighborhood safety and overweight status, and assessed the validity of reported neighborhood safety among a representative community sample of urban adolescents (who were racially and ethnically diverse).

Methods

Data come from the 2006 Boston Youth Survey, a cross-sectional study in which public high school students in Boston, MA completed a pencil-and-paper survey. The study used a two-stage, stratified sampling design whereby schools and then 9^th–12^th grade classrooms within schools were selected (the analytic sample included 1,140 students). Students reported their perceptions of neighborhood safety and several associated dimensions. With self-reported height and weight data, we computed body mass index (BMI, kg/m²) for the adolescents based on CDC growth charts. Chi-square statistics and corresponding p-values were computed to compare perceived neighborhood safety by the several associated dimensions. Prevalence ratios (PRs) and 95% confidence intervals (CI) were calculated to examine the association between perceived neighborhood safety and the prevalence of overweight status controlling for relevant covariates and school site.

Results

More than one-third (35.6%) of students said they always felt safe in their neighborhood, 43.9% said they sometimes felt safe, 11.6% rarely felt safe, and 8.9% never felt safe. Those students who reported that they rarely or never feel safe in their neighborhoods were more likely than those who said they always or sometimes feel safe to believe that gang violence was a serious problem in their neighborhood or school (68.0% vs. 44.1%, p < 0.001), and to have seen someone in their neighborhood assaulted with a weapon (other than a firearm) in the past 12 months (17.8% vs. 11.3%, p = 0.025). In the fully adjusted model (including grade and school) stratified by race/ethnicity, we found a statistically significant association between feeling unsafe in one's own neighborhood and overweight status among those in the Other race/ethnicity group [(PR = 1.56, (95% CI: 1.02, 2.40)].

Conclusion

Data suggest that perception of neighborhood safety may be associated with overweight status among urban adolescents in certain racial/ethnic groups. Policies and programs to address neighborhood safety may also be preventive for adolescent overweight.

Geographic disparities in colorectal cancer survival

BACKGROUND

Examining geographic variation in cancer patient survival can help identify important prognostic factors that are linked by geography and generate hypotheses about the underlying causes of survival disparities. In this study, we apply a recently developed spatial scan statistic method, designed for time-to-event data, to determine whether colorectal cancer (CRC) patient survival varies by place of residence after adjusting survival times for several prognostic factors.

METHODS

Using data from a population-based, statewide cancer registry, we examined a cohort of 25,040 men and women from New Jersey who were newly diagnosed with local or regional stage colorectal cancer from 1996 through 2003 and followed to the end of 2006. Survival times were adjusted for significant prognostic factors (sex, age, stage at diagnosis, race/ethnicity and census tract socioeconomic deprivation) and evaluated using a spatial scan statistic to identify places where CRC survival was significantly longer or shorter than the statewide experience.

RESULTS

Age, sex and stage adjusted survival times revealed several areas in the northern part of the state where CRC survival was significantly different than expected. The shortest and longest survival areas had an adjusted 5-year survival rate of 73.1% (95% CI 71.5, 74.9) and 88.3% (95% CI 85.4, 91.3) respectively, compared with the state average of 80.0% (95% CI 79.4, 80.5). Analysis of survival times adjusted for age, sex and stage as well as race/ethnicity and area socioeconomic deprivation attenuated the risk of death from CRC in several areas, but survival disparities persisted.

CONCLUSION

The results suggest that in areas where additional adjustments for race/ethnicity and area socioeconomic deprivation changed the geographic survival patterns and reduced the risk of death from CRC, the adjustment factors may be contributing causes of the disparities. Further studies should focus on specific and modifiable individual and neighborhood factors in the high risk areas that may affect a person's chance of surviving cancer.