Reduction in Breast Cancer Death With Adjuvant Chemotherapy Among US Women According to Race, Ethnicity, and the 21-Gene Recurrence Score.

BACKGROUND: We previously showed the 21-gene breast recurrence score (RS) has lower prognostic accuracy for non-Hispanic Black (NHB) compared with non-Hispanic White (NHW) women with estrogen receptor (ER)-positive/HER2-negative breast cancer. The purpose of this study was to determine the clinical validity of the RS for predicting chemotherapy benefit as recommended in the current NCCN Guidelines for Breast Cancer among women from diverse racial/ethnic groups. METHODS: Using the SEER Oncotype database, we estimated propensity score-weighted hazard ratios (HRs) and 95% confidence intervals for breast cancer death with chemotherapy for women with ER-positive/HER2-negative, AJCC stages I-II, axillary node-negative, invasive breast cancer according to race/ethnicity. RESULTS: We included 6,033 (8.2%) Asian/Pacific Islander (API), 5,697 (7.8%) NHB, 6,688 (9.1%) Hispanic, and 54,945 (74.9%) NHW women. Breast cancer death was reduced with chemotherapy for NHB (HR, 0.48, 95% CI, 0.28-0.81), Hispanic (HR, 0.48; 95% CI, 0.25-0.94), and NHW (HR, 0.80; 95% CI, 0.65-0.99) women with an RS of 26 to 100. There was a nonsignificant reduction for API women (HR, 0.59; 95% CI, 0.28-1.24). For women with an RS of 11 to 25, there was no reduction in death for any racial/ethnic group. Among women aged ≤50 years, the reduction in breast cancer death with chemotherapy differed according to race (NHB: HR, 0.37 [95% CI, 0.20-0.67]; NHW: HR, 0.56 [95% CI, 0.44-0.74]; Pinteraction for chemotherapy * race <.0499). An exploratory subgroup analysis found that young NHB women may benefit from chemotherapy at a lower RS cutoff than other women. CONCLUSIONS: The RS was clinically validated as a predictive biomarker for NHB, Hispanic, and NHW women with ER-positive, axillary node-negative breast cancer, but it may underestimate the benefit of chemotherapy for young NHB women. If this finding is confirmed, the RS cutoff for recommending adjuvant chemotherapy for young NHB women with ER-positive, axillary node-negative breast cancer may need to be lower than for other women.

Risk of contralateral breast cancer among Asian/Pacific Islander women in the United States.

PURPOSE: While breast cancer studies often aggregate Asian/Pacific Islander (API) women, as a single group or exclude them, this population is heterogeneous in terms of genetic background, environmental exposures, and health-related behaviors, potentially resulting in different cancer outcomes. Our purpose was to evaluate risks of contralateral breast cancer (CBC) among subgroups of API women with breast cancer. METHODS: We conducted a retrospective cohort study of women ages 18 + years diagnosed with stage I-III breast cancer between 2000 and 2016 in the Surveillance, Epidemiology and End Results registries. API subgroups included Chinese, Japanese, Filipina, Native Hawaiian, Korean, Vietnamese, Indian/Pakistani, and other API women. Asynchronous CBC was defined as breast cancer diagnosed in the opposite breast 12 + months after first primary unilateral breast cancer. Multivariable-adjusted subdistribution hazard ratios (SHR) and 95% confidence intervals (CI) were estimated and stratified by API subgroups. RESULTS: From a cohort of 44,362 API women with breast cancer, 25% were Filipina, 18% were Chinese, 14% were Japanese, and 8% were Indian/Pakistani. API women as an aggregate group had increased risk of CBC (SHR 1.15, 95% CI 1.08-1.22) compared to NHW women, among whom Chinese (SHR 1.23, 95% CI 1.08-1.40), Filipina (SHR 1.37, 95% CI 1.23-1.52), and Native Hawaiian (SHR 1.69, 95% CI 1.37-2.08) women had greater risks. CONCLUSION: Aggregating or excluding API patients from breast cancer studies ignores their heterogeneous health outcomes. To advance cancer health equity among API women, future research should examine inequities within the API population to design interventions that can adequately address their unique differences.

Association of Social Determinants and Tumor Biology With Racial Disparity in Survival From Early-Stage, Hormone-Dependent Breast Cancer.

Importance: Black women with hormone receptor-positive breast cancer experience the greatest racial disparity in survival of all breast cancer subtypes. The relative contributions of social determinants of health and tumor biology to this disparity are uncertain. Objective: To determine the proportion of the Black-White disparity in breast cancer survival from estrogen receptor (ER)-positive, axillary node-negative breast cancer that is associated with adverse social determinants and high-risk tumor biology. Design, Setting, and Participants: A retrospective mediation analysis of factors associated with the racial disparity in breast cancer death for cases diagnosed between 2004 and 2015 with follow-up through 2016 was carried out using the Surveillance, Epidemiology, and End Results (SEER) Oncotype registry. The study included women in the SEER-18 registry who were aged 18 years or older at diagnosis of a first primary invasive breast cancer tumor that was axillary node-negative and ER-positive, who were Black (Black), non-Hispanic White (White), and for whom the 21-gene breast recurrence score was available. Data analysis took place between March 4, 2021, and November 15, 2022. Exposures: Census tract socioeconomic disadvantage, insurance status, tumor characteristics including the recurrence score, and treatment variables. Main Outcomes and Measures: Death due to breast cancer. Results: The analysis with 60 137 women (mean [IQR] age 58.1 [50-66] years) included 5648 (9.4%) Black women and 54 489 (90.6%) White women. With a median (IQR) follow-up time of 56 (32-86) months, the age-adjusted hazard ratio (HR) for breast cancer death among Black compared with White women was 1.82 (95% CI, 1.51-2.20). Neighborhood disadvantage and insurance status together mediated 19% of the disparity (mediated HR, 1.62; 95% CI, 1.31-2.00; P < .001) and tumor biological characteristics mediated 20% (mediated HR, 1.56; 95% CI, 1.28-1.90; P < .001). A fully adjusted model that included all covariates accounted for 44% of the racial disparity (mediated HR, 1.38; 95% CI, 1.11-1.71; P < .001). Neighborhood disadvantage mediated 8% of the racial difference in the probability of a high-risk recurrence score (P = .02). Conclusions and Relevance: In this study, racial differences in social determinants of health and indicators of aggressive tumor biology including a genomic biomarker were equally associated with the survival disparity in early-stage, ER-positive breast cancer among US women. Future research should examine more comprehensive measures of socioecological disadvantage, molecular mechanisms underlying aggressive tumor biology among Black women, and the role of ancestry-related genetic variants.

Lifestyle change program engagement in real-world clinical practice: a mixed-methods analysis.

Participant engagement in structured lifestyle change programs (LCPs) is essential for adopting behaviors that promote weight loss; however, the challenges to, and facilitators that promote, engagement with such programs are not well understood. We conducted a mixed-methods study among real-world LCP participants to assess factors associated with program engagement and to examine the reasons for withdrawal. Using electronic health records (EHR), we identified LCP eligible participants between 2010 and 2017. Multivariable logistic regression was used to assess associations between program engagement and baseline characteristics. Semi-structured interviews with LCP participants were conducted and thematically analyzed to examine reasons for withdrawal. A total of 1,813 LCP participants were included. The median number of sessions attended was 10 of 21-25 sessions. Highest LCP engagement was associated with factors potentially related to self-efficacy/motivation, such as older age, higher baseline weight, prior healthcare utilization and an absence of a history of smoking or depression. Engagement was also negatively associated with being Non-Hispanic Black versus White. The qualitative analysis of the interviews revealed four general themes pertaining to participants' withdrawal: competing priorities, perceived program effectiveness, characteristics of the program, and facilitator-related factors. Taken together, results from this mixed-methods study suggest that motivation and self-efficacy are important for program engagement; future LCP enhancements should incorporate flexible formats that may help participants manage competing priorities and maximize personal and cultural relevance for all racial/ethnic groups, especially those who have not benefitted fully. Furthermore, participants should be encouraged to set realistic goals to manage expectations.

Engaging in a structured lifestyle change program (LCP) is essential to learn healthy behaviors, however, it is not well understood. This study examined factors associated with program engagement and reasons for program withdrawal at a large healthcare system. Highest LCP engagement was found to be associated to factors potentially related to self-efficacy/motivation including older age, higher initial weight, and prior healthcare utilization. Non-Hispanic Black, history of smoking, and prior diagnosis of depression were found to be negatively associated with LCP engagement. Program withdrawal was related to four themes: competing priorities, perceived program effectiveness, characteristics of the program, and facilitator-related factors. These findings suggest that motivation and self-efficacy are important for behavior change program engagement.

Impact of socioeconomic status and rurality on cancer-specific survival among women with de novo metastatic breast cancer by race/ethnicity.

PURPOSE: There are approximately 150,000 women living with metastatic breast cancer (mBC) in the United States. Disparities in de novo mBC incidence and mortality exist across race/ethnicity, socioeconomic status (SES), and rurality. However, how SES and rurality independently impact mBC outcomes across different racial/ethnic groups is not fully understood. The purpose of this study was to determine the impact of SES and rurality on cancer-specific mortality among women with mBC by race/ethnicity. METHODS: We conducted a large, population-based retrospective cohort study in women aged 18 + years diagnosed with de novo mBC using the Surveillance, Epidemiology and End Results Census Tract-level SES and Rurality Database (2000-2015). Associations between SES/rurality and cancer-specific mortality were determined using Fine and Gray regression models. Subdistribution hazard ratios (SHR) and 95% confidence intervals (CI) by race/ethnicity and hormone receptor (HR) status were calculated. RESULTS: A cohort of 33,976 women were included with the majority being White (67%), 17% Black, 0.4% American Indian/Alaskan Native, 6% Asian/Pacific Islander, and 10% Latina/Hispanic. We observed the greatest increased risk of BC mortality among Black women with HR-negative mBC residing in neighborhoods with lower SES (lowest versus highest quintile: SHR 1.38, 95% CI 1.00-1.90) and in rural areas compared to urban areas (SHR 1.27, 95% CI 1.01-1.59). CONCLUSION: Overall, BC-specific survival among women with de novo mBC differs by race/ethnicity, with the greatest adverse impacts of SES and rurality affecting Black women with HR-negative disease.