The Effect of Patient and Contextual Characteristics on Racial/Ethnic Disparity in Breast Cancer Mortality

Correlates of health-related quality of life in African Americans diagnosed with cancer: a review of survivorship studies and the Detroit research on cancer survivors cohort

Advances in cancer screening and treatment have improved survival after a diagnosis of cancer. As the number of cancer survivors as well as their overall life-expectancy increases, investigations of health-related quality of life (HRQOL) are critical in understanding the factors that promote the optimal experience over the course of survivorship. However, there is a dearth of information on determinants of HRQOL for African American cancer survivors as the vast majority of cohorts have been conducted predominantly among non-Hispanic Whites. In this review, we provide a review of the literature related to HRQOL in cancer survivors including those in African Americans. We then present a summary of published work from the Detroit Research on Cancer Survivors (ROCS) cohort, a population-based cohort of more than 5000 African American cancer survivors. Overall, Detroit ROCS has markedly advanced our understanding of the unique factors contributing to poorer HRQOL among African Americans with cancer. This work and future studies will help inform potential interventions to improve the long-term health of this patient population.

Impact of patient demographics and neighborhood socioeconomic variables on clinical trial participation patterns for NHL

ABSTRACT

Prior studies have demonstrated that certain populations including older patients, racial/ethnic minority groups, and women are underrepresented in clinical trials. We performed a retrospective analysis of patients with non-Hodgkin lymphoma (NHL) seen at MD Anderson Cancer Center (MDACC) to investigate the association between trial participation, race/ethnicity, travel distance, and neighborhood socioeconomic status (nSES). Using patient addresses, we ascertained nSES variables on educational attainment, income, poverty, racial composition, and housing at the census tract (CT) level. We also performed geospatial analysis to determine the geographic distribution of clinical trial participants and distance from patient residence to MDACC. We examined 3146 consecutive adult patients with NHL seen between January 2017 and December 2020. The study cohort was predominantly male and non-Hispanic White (NHW). The most common insurance types were private insurance and Medicare; only 1.1% of patients had Medicaid. There was a high overall participation rate of 30.5%, with 20.9% enrolled in therapeutic trials. In univariate analyses, lower participation rates were associated with lower nSES including higher poverty rates and living in crowded households. Racial composition of CT was not associated with differences in trial participation. In multivariable analysis, trial participation varied significantly by histology, and participation declined nonlinearly with age in the overall, follicular lymphoma, and diffuse large B-cell lymphoma (DLBCL) models. In the DLBCL subset, Hispanic patients had lower odds of participation than White patients (odds ratio, 0.36; 95% confidence interval, 0.21-0.62; P = .001). In our large academic cohort, race, sex, insurance type, and nSES were not associated with trial participation, whereas age and diagnosis were.

Trends in surgical treatment of early-stage breast cancer reveal decreasing mastectomy use between 2003 and 2016 by age, race, and rurality

PURPOSE

To examine trends in the surgical treatment of breast cancer by age, rurality, and among Black women in a populous, racially diverse, state in the Southeastern United States of America.

METHODS

We identified women diagnosed with localized or regional breast cancer between 2003 and 2016 in the North Carolina Central Cancer Registry (n = 86,776). Using Joinpoint regression we evaluated the average annual percentage change in proportion of women treated with mastectomy versus breast-conserving surgery overall, by age group, among Black women, and for women residing in rural areas.

RESULTS

Overall, the rate of mastectomy usage in the population declined 2.5% per year between 2003 and 2016 (95% CI - 3.2, - 1.7). Over this same time interval, breast-conserving surgery increased by 1.6% per year (95% CI 0.9, 2.2). These temporal trends in surgery were also observed among Black women and rural residing women. Trends in surgery type varied by age group: mastectomy declined over time among women > 50 years, but not among women aged 18-49 at diagnosis.

DISCUSSION

In contrast to national studies that reported increasing use of mastectomy, we found declining mastectomy rates in the early 2000s in a Southern US state with a racially and geographically diverse population. These decreasing trends were consistent among key subgroups affected by cancer inequities, including Black and White rural women.

A Novel Mixed Methods Approach Combining Geospatial Mapping and Qualitative Inquiry to Identify Multilevel Policy Targets: The Focused Rapid Assessment Process (fRAP) Applied to Cancer Survivorship

Multi-level perspectives across communities, medical systems and policy environments are needed, but few methods are available for health services researchers with limited resources. We developed a mixed method health policy approach, the focused Rapid Assessment Process (fRAP), that is designed to uncover multi-level modifiable barriers and facilitators contributing to public health issues. We illustrate with a study applying fRAP to the issue of cancer survivorship care. Through this multi-level investigation we identified two major modifiable areas impacting high-quality cancer survivorship care: 1) the importance of cancer survivorship guidelines/data, 2) the need for improved oncology-primary care relationships. This article contributes to the mixed methods literature by coupling geospatial mapping to qualitative rapid assessment to efficiently identify policy change targets.

Contributions of Social Factors to Disparities in Prostate Cancer Risk Profiles among Black Men and Non-Hispanic White Men with Prostate Cancer in California

BACKGROUND

Black men are more likely than Non-Hispanic White (NHW) men to be diagnosed with high-risk prostate cancer. We examined the extent to which social factors were associated with differences in prostate cancer risk profiles between Black men and NHW men [using a modification to the original D'Amico risk groups based on prostate specific antigen (PSA), Gleason score (GS), and TNM stage (stage)], based on individual and combined clinicopathologic characteristics.

METHODS

We conducted a cross-sectional population-based study of 23,555 Black men and 146,889 NHW men diagnosed with prostate cancer in the California Cancer Registry from 2004 to 2017. We conducted multivariable logistic regression to examine the association of year of diagnosis, block group-level neighborhood socioeconomic status (nSES), marital status, and insurance type on differences in prostate cancer risk profiles between Black and NHW men.

RESULTS

High PSA (>20 ng/mL), GS, stage, individually and combined prostate cancer risk profiles were more common among Black men versus NHW men. In fully adjusted models, relative to NHW men, we observed a persistent 67% increased odds of high PSA among Black men. nSES was the factor most strongly associated with racial disparity in high PSA, accounting for 25% of the difference. Marital status was the factor that was second most associated with a racial disparity.

CONCLUSIONS

nSES was the factor most strongly associated with racial disparities in high PSA prostate cancer.

IMPACT

The influence of nSES on racial disparities in PSA, GS, stage, and prostate cancer risk profiles warrants further consideration.

Naïve Bayesian network-based contribution analysis of tumor biology and healthcare factors to racial disparity in breast cancer stage-at-diagnosis

BACKGROUND

Variation in breast cancer stage at initial diagnosis (including racial disparities) is driven both by tumor biology and healthcare factors.

METHODS

We studied women age 67-74 with initial diagnosis of breast cancer from 2006 through 2014 in the SEER-Medicare database. We extracted variables related to tumor biology (histologic grade and hormone receptor status) and healthcare factors (screening mammography [SM] utilization and time delay from mammography to diagnostic biopsy). We used naïve Bayesian networks (NBNs) to illustrate the relationships among patient-specific factors and stage-at-diagnosis for African American (AA) and white patients separately. After identifying and controlling confounders, we conducted counterfactual inference through the NBN, resulting in an unbiased evaluation of the causal effects of individual factors on the expected utility of stage-at-diagnosis. An NBN-based decomposition mechanism was developed to evaluate the contributions of each patient-specific factor to an actual racial disparity in stage-at-diagnosis. 2000 bootstrap samples from our training patients were used to compute the 95% confidence intervals (CIs) of these contributions.

RESULTS

Using a causal-effect contribution analysis, the relative contributions of each patient-specific factor to the actual racial disparity in stage-at-diagnosis were as follows: tumor grade, 45.1% (95% CI: 44.5%, 45.8%); hormone receptor status, 5.0% (4.5%, 5.4%); mammography utilization, 23.1% (22.4%, 24.0%); and biopsy delay 26.8% (26.1%, 27.3%).

CONCLUSION

The modifiable mechanisms of mammography utilization and biopsy delay drive about 49.9% of racial difference in stage-at-diagnosis, potentially guiding more targeted interventions to eliminate cancer outcome disparities.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13755-021-00165-5.

Racial/ethnic disparities in risk of breast cancer mortality by molecular subtype and stage at diagnosis

PURPOSE

Previous research has found significant survival disparities between Black and White women among select stages and subtypes of breast cancer, however other racial/ethnic groups have been less well-studied. This study expands on previous research, examining differences in breast cancer-specific mortality across multiple racial and ethnic groups.

METHODS

Women diagnosed with a first primary invasive breast cancer between 2010 and 2016 who were 20-85 years of age at diagnosis were identified from 18 Surveillance, Epidemiology, and End Results (SEER) registries. Subtypes were defined by joint hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status. Cox proportional hazards models for each stage and subtype were fit, with non-Hispanic white women as the reference group. Effect modification by age at diagnosis (< 50, ≥ 50) was found and thus analyses were age-stratified.

RESULTS

After multivariable adjustment, younger Black women had greater risks of breast cancer-specific death for all stages of HR+/HER2-, and certain stages of HR+/HER2+ , TN, and HR-/HER2 + breast cancer. Asian/Pacific Islander women generally had a lower hazard of breast cancer-specific death. Older Hispanic White women had a lower hazard of breast cancer-specific death for stages I-III HR + /HER2- and stage II TN breast cancer.

CONCLUSIONS

These findings demonstrate that different racial/ethnic groups experience different risks of breast cancer-specific mortality by stage and subtype. Efforts to address survival disparities should place additional focus on young Black women, as they experience meaningful disparities in breast cancer-specific mortality.

Racial disparities in mortality for patients with prostate cancer after radical prostatectomy

BACKGROUND

Although racial disparities in prostate cancer survival are well documented, the relative importance of contributing factors remains unclear. Few studies have examined the disparity between Whites and Hispanics or between Whites and Asian Americans and Pacific Islanders (AAPIs).

METHODS

Using data from the National Cancer Database for 526,690 patients with prostate cancer who underwent radical prostatectomy between 2004 and 2014, this study systematically evaluated the impact of clinical characteristics and factors related to access to care on survival by race. Included in the analysis were 432,640 White patients (82.1%), 63,602 Black patients (12.1%), 8990 AAPI patients (1.7%), and 21,458 Hispanic patients (4.1%). Multivariable Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals to measure racial survival disparities. Inverse probability weighting was used to adjust for imbalances of prognostic factors.

RESULTS

When adjustments were made for age and year of diagnosis only, Blacks had 51% higher mortality, AAPIs had 22% lower mortality, and Hispanics had 6% lower mortality than Whites. Overall, with adjustments for all clinical factors and nonclinical factors, the Black-White survival disparity narrowed to 20%, whereas the AAPI-White disparity increased to 35%. Among the controlled-for factors, education, median household income, and insurance status contributed the most to the racial disparity.

CONCLUSIONS

The overall survival disparity among men undergoing radical prostatectomy was significantly decreased, but not eliminated, for Blacks and significantly increased for AAPIs in comparison with Whites after adjustments for a number of clinical factors and factors related to access to care.

Multilevel social factors and NICU quality of care in California

OBJECTIVE

Our objective was to incorporate social and built environment factors into a compendium of multilevel factors among a cohort of very low birth weight infants to understand their contributions to inequities in NICU quality of care and support providers and NICUs in addressing these inequities via development of a health equity dashboard.

STUDY DESIGN

We examined bivariate associations between NICU patient pool and NICU catchment area characteristics and NICU quality of care with data from a cohort of 15,901 infants from 119 NICUs in California, born 2008-2011.

RESULT

NICUs with higher proportion of minority racial/ethnic patients and lower SES patients had lower quality scores. NICUs with catchment areas of lower SES, higher composition of minority residents, and more household crowding had lower quality scores.

CONCLUSION

Multilevel social factors impact quality of care in the NICU. Their incorporation into a health equity dashboard can inform providers of their patients' potential resource needs.

Racial/Ethnic Disparities in Survival after Breast Cancer Diagnosis by Estrogen and Progesterone Receptor Status: A Pooled Analysis

BACKGROUND

Limited studies have investigated racial/ethnic survival disparities for breast cancer defined by estrogen receptor (ER) and progesterone receptor (PR) status in a multiethnic population.

METHODS

Using multivariable Cox proportional hazards models, we assessed associations of race/ethnicity with ER/PR-specific breast cancer mortality in 10,366 California women diagnosed with breast cancer from 1993 to 2009. We evaluated joint associations of race/ethnicity, health care, sociodemographic, and lifestyle factors with mortality.

RESULTS

Among women with ER/PR⁺ breast cancer, breast cancer-specific mortality was similar among Hispanic and Asian American women, but higher among African American women [HR, 1.31; 95% confidence interval (CI), 1.05-1.63] compared with non-Hispanic White (NHW) women. Breast cancer-specific mortality was modified by surgery type, hospital type, education, neighborhood socioeconomic status (SES), smoking history, and alcohol consumption. Among African American women, breast cancer-specific mortality was higher among those treated at nonaccredited hospitals (HR, 1.57; 95% CI, 1.21-2.04) and those from lower SES neighborhoods (HR, 1.48; 95% CI, 1.16-1.88) compared with NHW women without these characteristics. Breast cancer-specific mortality was higher among African American women with at least some college education (HR, 1.42; 95% CI, 1.11-1.82) compared with NHW women with similar education. For ER^-/PR^- disease, breast cancer-specific mortality did not differ by race/ethnicity and associations of race/ethnicity with breast cancer-specific mortality varied only by neighborhood SES among African American women.

CONCLUSIONS

Racial/ethnic survival disparities are more striking for ER/PR⁺ than ER^-/PR^- breast cancer. Social determinants and lifestyle factors may explain some of the survival disparities for ER/PR⁺ breast cancer.

IMPACT

Addressing these factors may help reduce the higher mortality of African American women with ER/PR⁺ breast cancer.

Breast Cancer Screening Recommendations: African American Women Are at a Disadvantage

Since 1990, breast cancer mortality has decreased by 40% in white women but only 26% in African American women. The age at diagnosis of breast cancer is younger in black women. Breast cancer diagnosed before age 50 represents 23% of all breast cancers in African American women but only 16% of all breast cancers in white women. White women have a higher incidence of breast cancer over the age of 60. Tumor subtypes also vary among racial and ethnic groups. The triple-negative (TN) subtype, which has a poorer outcome and occurs at a younger age, represents 21% of invasive breast cancers in black women but only 10% of invasive breast cancers in white women. The hormone receptor-positive subtype, which is more common in older women and has the best outcome, has a higher incidence in white women (70%) than in black women (61%). The BRCA2 mutation is also more common in black women than in white women (other than those who are of Ashkenazi Jewish ancestry). There are also many barriers to screening. Major ones include the lack of contact with a primary health care provider as well as a decreased perceived risk of having breast cancer in the African American population. Given the younger age of onset and the higher incidence of the TN molecular subtype, following breast cancer screening guidelines that do not support screening before the age of 50 may disadvantage black women.

Hospital Characteristics and Breast Cancer Survival in the California Breast Cancer Survivorship Consortium

INTRODUCTION

Racial/ethnic disparities in breast cancer survival are well documented, but the influence of health care institutions is unclear. We therefore examined the effect of hospital characteristics on survival.

METHODS

Harmonized data pooled from 5 case-control and prospective cohort studies within the California Breast Cancer Survivorship Consortium were linked to the California Cancer Registry and the California Neighborhoods Data System. The study included 9,701 patients with breast cancer who were diagnosed between 1993 and 2007. First reporting hospitals were classified by hospital type-National Cancer Institute (NCI) -designated cancer center, American College of Surgeons (ACS) Cancer Program, other-and hospital composition of the neighborhood socioeconomic status and race/ethnicity of patients with cancer. Multivariable Cox proportional hazards models adjusted for clinical and patient-level prognostic factors were used to examine the influence of hospital characteristics on survival.

RESULTS

Fewer than one half of women received their initial care at an NCI-designated cancer center (5%) or ACS program (38%) hospital. Receipt of initial care in ACS program hospitals varied by race/ethnicity-highest among non-Latina White patients (45%), and lowest among African Americans (21%). African-American women had superior breast cancer survival when receiving initial care in ACS hospitals versus other hospitals (non-ACS program and non-NCI-designated cancer center; hazard ratio, 0.67; 95% CI, 0.55 to 0.83). Other hospital characteristics were not associated with survival.

CONCLUSION

African American women may benefit significantly from breast cancer care in ACS program hospitals; however, most did not receive initial care at such facilities. Future research should identify the aspects of ACS program hospitals that are associated with higher survival and evaluate strategies by which to enhance access to and use of high-quality hospitals, particularly among African American women.

Racial and Ethnic Disparities in Human Milk Intake at Neonatal Intensive Care Unit Discharge among Very Low Birth Weight Infants in California

OBJECTIVES

To examine how infant and maternal factors, hospital factors, and neighborhood-level factors impact or modify racial/ethnic disparities in human milk intake at hospital discharge among very low birth weight infants.

STUDY DESIGN

We studied 14 422 infants from 119 California Perinatal Quality Care Collaborative neonatal intensive care units born from 2008 to 2011. Maternal addresses were linked to 2010 census tract data, representing neighborhoods. We tested for associations with receiving no human milk at discharge, using multilevel cross-classified models.

RESULTS

Compared with non-Hispanic whites, the adjusted odds of no human milk at discharge was higher among non-Hispanic blacks (aOR 1.33 [1.16-1.53]) and lower among Hispanics (aOR 0.83 [0.74-0.93]). Compared with infants of more educated white mothers, infants of less educated white, black, and Asian mothers had higher odds of no human milk at discharge, and infants of Hispanic mothers of all educational levels had similar odds as infants of more educated white mothers. Country of birth and neighborhood socioeconomic was also associated with disparities in human milk intake at discharge.

CONCLUSIONS

Non-Hispanic blacks had the highest and Hispanic infants the lowest odds of no human milk at discharge. Maternal education and country of birth were the biggest drivers of disparities in human milk intake, suggesting the need for targeted approaches of breastfeeding support.

The Impact of Neighborhood Economic and Racial Inequalities on the Spatial Variation of Breast Cancer Survival in New Jersey

BACKGROUND

Mapping breast cancer survival can help cancer control programs prioritize efforts with limited resources. We used Bayesian spatial models to identify whether breast cancer survival among patients in New Jersey (NJ) varies spatially after adjusting for key individual (age, stage at diagnosis, molecular subtype, race/ethnicity, marital status, and insurance) and neighborhood measures of poverty and economic inequality [index of concentration at the extremes (ICE)].

METHODS

Survival time was calculated for all NJ women diagnosed with invasive breast cancer between 2010 and 2014 and followed to December 31, 2015 (N = 27,078). Nonlinear geoadditive Bayesian models were used to estimate spatial variation in hazard rates and identify geographic areas of higher risk of death from breast cancer.

RESULTS

Significant geographic differences in breast cancer survival were found in NJ. The geographic variation of hazard rates statewide ranged from 0.71 to 1.42 after adjustment for age and stage, and were attenuated after adjustment for additional individual-level factors (0.87-1.15) and neighborhood measures, including poverty (0.9-1.11) and ICE (0.92-1.09). Neighborhood measures were independently associated with breast cancer survival, but we detected slightly stronger associations between breast cancer survival, and the ICE compared to poverty.

CONCLUSIONS

The spatial models indicated breast cancer survival disparities are a result of combined individual-level and neighborhood socioeconomic factors. More research is needed to understand the moderating pathways in which neighborhood socioeconomic status influences breast cancer survival.

IMPACT

More effective health interventions aimed at improving breast cancer survival could be developed if geographic variation were examined more routinely in the context of neighborhood socioeconomic inequalities in addition to individual characteristics.

The Detroit Research on Cancer Survivors (ROCS) Pilot Study: A Focus on Outcomes after Cancer in a Racially Diverse Patient Population

BACKGROUND

African Americans are often diagnosed with advanced stage cancer and experience higher mortality compared with whites in the United States. Contributing factors, like differences in access to medical care and the prevalence of comorbidities, do not entirely explain racial differences in outcomes.

METHODS

The Detroit Research on Cancer Survivors (ROCS) pilot study was conducted to investigate factors related to short- and long-term outcomes among patients with cancer. Participants completed web-based surveys, and mailed saliva specimens were collected for future genetic studies.

RESULTS

We recruited 1,000 participants with an overall response rate of 68%. Thirty-one percent completed the survey without any interviewer support and the remaining participated in an interviewer-administered survey. Seventy-four percent provided a saliva specimen and 64% consented for tumor tissue retrieval. African American survivors required more interviewer support (P < 0.001); however, their response rate (69.6%) was higher than non-Hispanic whites (65.4%). African Americans reported poorer overall cancer-related quality of life compared with non-Hispanic whites, measured by FACT-G score (P < 0.001), however, this relationship was reversed after controlling for socioeconomic factors, marital status, and the presence of comorbidities.

CONCLUSIONS

In this pilot study, we demonstrated that a web-based survey supplemented with telephone interviews and mailed saliva kits are cost-effective methods to collect patient-reported data and DNA for large studies of cancer survivors with a high proportion of minority patients. The preliminary data collected reinforces differences by race in factors affecting cancer outcomes. Our efforts continue as we expand this unique cohort to include more than 5,000 African American cancer survivors.

IMPACT

Formal investigation of factors influencing adverse outcomes among African American cancer survivors will be critical in closing the racial gap in morbidity and mortality.

Predictors of breast cancer mortality among white and black women in large United States cities: an ecologic study

PURPOSE

We employed a city-level ecologic analysis to assess predictors of race-specific (black and white) breast cancer mortality rates.

METHODS

We used data from the National Center for Health Statistics and the US Census Bureau to calculate 2010-2014 race-specific breast cancer mortality rates (BCMR) for 47 of the largest US cities. Data on potential city-level predictors (e.g., socioeconomic factors, health care resources) of race-specific BCMR were obtained from various publicly available datasets. We constructed race-specific multivariable negative binomial regression models to estimate rate ratios (RR) and 95% confidence intervals (CIs).

RESULTS

Predictors of the white BCMR included white/black differences in education (RR 0.95; CI 0.91-0.99), number of religious congregations (RR 0.87; CI 0.77-0.97), and number of Medicare primary care physicians (RR 1.15; CI 1.04-1.28). Predictors of the black rate included white/black differences in household income (RR 1.03; CI 1.01-1.05), number of mammography facilities (RR 1.07; CI 1.03-1.12), and mammogram use (RR 0.93; CI 0.89-0.97).

CONCLUSIONS

Our ecologic analysis found that predictors of breast cancer mortality differ for the black and white rate. The results of this analysis could help inform interventions at the local level.

Racial/ethnic differences in the outcomes of patients with metastatic breast cancer: contributions of demographic, socioeconomic, tumor and metastatic characteristics

PURPOSE

Population-based estimates of racial disparities in metastatic breast cancer are lacking. We quantified the contributions of demographic, socioeconomic, tumor, and metastatic characteristics to racial differences in metastatic breast cancer and characterized the most disproportional subgroup.

METHODS

Patients diagnosed with metastatic breast cancer between 2010 and 2014 were identified using the Surveillance, Epidemiology, and End Results database. A multivariable Cox proportional hazards model was used to adjust each set of variables. The excess relative risk of cancer-specific and all-cause death in non-Hispanic black (NHB) versus non-Hispanic white women diagnosed with metastatic breast cancer was expressed as a percentage and was stratified by the age at diagnosis.

RESULTS

We identified 13,066 female patients. NHB women exhibited substantially higher morbidity and mortality than women of other races/ethnicities. The greatest excess mortality risk for NHB women was observed in the young-onset group (18-49 years; hazard ratio: 1.57), followed by the middle-age group (50-64 years; hazard ratio: 1.42); the trend was not significant among the elderly group. Socioeconomic factors stably explained one-half of the excess risk, whereas the contribution of tumor characteristics obviously decreased with age (18-49 years, 40.7%; 50-64 years, 33.9%), and the metastatic pattern accounted for approximately one-tenth of the excess risk. Additionally, the disproportional death burden of NHB women persisted in less aggressive subgroups.

CONCLUSIONS

By providing a comprehensive assessment of racial differences in the incidence and outcomes of patients with metastatic breast cancer, we urge the implementation of targeted preventive efforts in both the public health and clinical arenas.

Literature review of data-based models for identification of factors associated with racial disparities in breast cancer mortality

In the United States, early detection methods have contributed to the reduction of overall breast cancer mortality but this pattern has not been observed uniformly across all racial groups. A vast body of research literature shows a set of health care, socio-economic, biological, physical, and behavioural factors influencing the mortality disparity. In this paper, we review the modelling frameworks, statistical tests, and databases used in understanding influential factors, and we discuss the factors documented in the modelling literature. Our findings suggest that disparities research relies on conventional modelling and statistical tools for quantitative analysis, and there exist opportunities to implement data-based modelling frameworks for (1) exploring mechanisms triggering disparities, (2) increasing the collection of behavioural data, and (3) monitoring factors associated with the mortality disparity across time.

Racial and Ethnic Disparities in Cancer Survival: The Contribution of Tumor, Sociodemographic, Institutional, and Neighborhood Characteristics

Purpose Racial/ethnic disparities in cancer survival in the United States are well documented, but the underlying causes are not well understood. We quantified the contribution of tumor, treatment, hospital, sociodemographic, and neighborhood factors to racial/ethnic survival disparities in California. Materials and Methods California Cancer Registry data were used to estimate population-based cancer-specific survival for patients diagnosed with breast, prostate, colorectal, or lung cancer between 2000 and 2013 for each racial/ethnic group (non-Hispanic black, Hispanic, Asian American and Pacific Islander, and separately each for Chinese, Japanese, and Filipino) compared with non-Hispanic whites. The percentage contribution of factors to overall racial/ethnic survival disparities was estimated from a sequence of multivariable Cox proportional hazards models. Results In baseline models, black patients had the lowest survival for all cancer sites, and Asian American and Pacific Islander patients had the highest, compared with whites. Mediation analyses suggested that stage at diagnosis had the greatest influence on overall racial/ethnic survival disparities accounting for 24% of disparities in breast cancer, 24% in prostate cancer, and 16% to 30% in colorectal cancer. Neighborhood socioeconomic status was an important factor in all cancers, but only for black and Hispanic patients. The influence of marital status on racial/ethnic disparities was stronger in men than in women. Adjustment for all covariables explained approximately half of the overall survival disparities in breast, prostate, and colorectal cancer, but it explained only 15% to 40% of disparities in lung cancer. Conclusion Overall reductions in racial/ethnic survival disparities were driven largely by reductions for black compared with white patients. Stage at diagnosis had the largest effect on racial/ethnic survival disparities, but earlier detection would not entirely eliminate them. The influences of neighborhood socioeconomic status and marital status suggest that social determinants, support mechanisms, and access to health care are important contributing factors.

Relationships between social isolation, neighborhood poverty, and cancer mortality in a population-based study of US adults

BACKGROUND

Social isolation is an important determinant of all-cause mortality, with evidence suggesting an association with cancer-specific mortality as well. In this study, we examined the associations between social isolation and neighborhood poverty (independently and jointly) on cancer mortality in a population-based sample of US adults.

METHODS

Using data from the Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994), NHANES III Linked Mortality File (through 2011) and 1990 Census, we estimated the relationship between social isolation and high neighborhood poverty and time-to-cancer death using multivariable-adjusted Cox proportional hazards models. We examined the associations of each factor independently and explored the multiplicative and additive interaction effects on cancer mortality risk and also analyzed these associations by sex.

RESULTS

Among 16 044 US adults with 17-23 years of follow-up, there were 1133 cancer deaths. Social isolation (HR 1.25, 95% CI: 1.01-1.54) and high neighborhood poverty (HR 1.31, 95% CI: 1.08-1.60) were associated with increased risk of cancer mortality adjusting for age, sex, and race/ethnicity; in sex-specific estimates this increase in risk was evident among females only (HR 1.39, 95% CI: 1.04-1.86). These associations were attenuated upon further adjustment for socioeconomic status. There was no evidence of joint effects of social isolation and high neighborhood poverty on cancer mortality overall or in the sex-stratified models.

CONCLUSIONS

These findings suggest that social isolation and higher neighborhood poverty are independently associated with increased risk of cancer mortality, although there is no evidence to support our a priori hypothesis of a joint effect.

Genetics of triple-negative breast cancer: Implications for patient care

Patients with triple-negative breast cancer (TNBC), defined as lacking expression of the estrogen and progesterone receptors (ER/PR) and amplification of the HER2 oncogene, often have a more aggressive disease course than do patients with hormone receptor-positive breast cancer, including higher rates of visceral and central nervous system metastases, early cancer recurrences and deaths. Triple-negative breast cancer is associated with a young age at diagnosis and both African and Ashkenazi Jewish ancestry, the latter due to three common founder mutations in the highly penetrant cancer susceptibility genes BRCA1 and BRCA2 (BRCA1/2). In the past decade, there has been a surge both in genetic testing technology and in patient access to such testing. Advances in genetic testing have enabled more rapid and less expensive commercial sequencing than could be imagined only a few years ago. Massively parallel, next-generation sequencing allows the simultaneous analysis of many different genes. Studies of TNBC patients in the current era have revealed associations of TNBC with mutations in several moderate penetrance breast cancer susceptibility genes, including PALB2, BARD1, BRIP1, RAD51C and RAD51D. Interestingly, many of these genes, like BRCA1/2, are involved in homologous recombination DNA double-stranded repair. In this review, we summarize the current understanding of pathogenic germline gene mutations associated with TNBC and the early detection and prevention strategies for women at risk of developing this high-risk breast cancer subtype. Furthermore, we discuss recent the advances in targeted therapies for TNBC patients with a hereditary predisposition, including the role of poly (ADP-ribose) polymerase (PARP) inhibitors in BRCA1/2 mutation-associated breast cancers.