Racial/ethnic differences in use and duration of adjuvant hormonal therapy for breast cancer in the women's health initiative

Extended adjuvant endocrine therapy in a longitudinal cohort of young breast cancer survivors

Extended adjuvant endocrine therapy (eET) improves outcomes in breast cancer survivors. Most studies however have been limited to postmenopausal women, and optimal eET for young survivors is uncertain. We report eET use among participants in the Young Women's Breast Cancer Study (YWS), a multicenter prospective cohort of women age ≤40 newly diagnosed with breast cancer enrolled between 2006-2016. Women with stage I-III hormone receptor-positive breast cancer, ≥6 years from diagnosis without recurrence were considered eET candidates. Use of eET was elicited from annual surveys sent years 6-8 after diagnosis, censoring for recurrence/death. 663 women were identified as eET candidates with 73.9% (490/663) having surveys eligible for analysis. Among eligible participants, mean age was 35.5 (±3.9), 85.9% were non-Hispanic white, and 59.6% reported eET use. Tamoxifen monotherapy was the most reported eET (77.4%), followed by aromatase inhibitor (AI) monotherapy (21.9%), AI-ovarian function suppression (AI-OFS) (6.8%) and tamoxifen-OFS (3.1%). In multivariable analysis, increasing age (per year odds ratio [OR]: 1.10, 95% confidence interval [CI]: 1.04-1.16), stage (II v. I: OR: 2.86, 95% CI: 1.81-4.51; III v. I: OR: 3.73, 95%CI: 1.87-7.44) and receipt of chemotherapy (OR: 3.66, 95% CI: 2.16-6.21) were significantly associated with eET use. Many young breast cancer survivors receive eET despite limited data regarding utility in this population. While some factors associated with eET use reflect appropriate risk-based care, potential sociodemographic disparities in uptake warrants further investigation in more diverse populations.

Association of Endocrine Therapy Initiation Timeliness With Adherence and Continuation in Low-Income Women With Breast Cancer

IMPORTANCE

Though adjuvant endocrine therapy (AET) has proven efficacy in treating hormone receptor-positive (HR-positive) breast cancer, patient adherence to AET and continuation of treatment as recommended by guidelines remain suboptimal, especially for low-income patients.

OBJECTIVE

To quantify timelines for initiating AET and assess their association with short- and long-term adherence and continuation of AET in low-income women with breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study included women younger than 65 years diagnosed with first primary HR-positive breast cancer between January 1, 2007, and December 31, 2013, followed up for 5 years after the first use of AET through December 2018, and identified from the linked Missouri Cancer Registry and Medicaid claims data set.

EXPOSURES

Time to initiation (TTI) as days from the date of last treatment (surgery, radiotherapy, or chemotherapy) to the first date of AET prescription fill.

MAIN OUTCOMES AND MEASURES

The main outcomes were adherence to AET as medication possession ratio of 80% or greater and continuation of AET as no gap in medication supply for at least 90 days. Odds ratios (ORs) of adherence and continuation over 1 to 5 years were estimated using logistic regression adjusted for demographic, clinical, and neighborhood variables. Analyses were performed between September 1, 2020, and May 31, 2022.

RESULTS

Among 1711 patients, median TTI was 53 (IQR, 26-117) days. A total of 1029 patients (60.1%) were aged 50 to 64 years old, 1270 (74.2%) were non-Hispanic White, and 1133 (66.2%) were unmarried. In the first year after initiation, 1317 (77.0%) were adherent and 1015 (59.3%) continued AET. Over the full 5 years, 376 (22.0%) were adherent and 409 (23.9%) continued AET. Longer TTI was significantly associated with poorer adherence at every year, with an OR of 0.97 (95% CI, 0.95-0.99) for 1-year adherence and an OR of 0.94 (95% CI, 0.90-0.97) for 5-year adherence per 1-month increase in TTI. Longer TTI was also associated with lower odds of short-term, but not long-term, continuation (OR, 0.97 [95% CI, 0.95-0.99] for 1-year continuation and 0.98 [95% CI, 0.96-0.99] for 2-year continuation).

CONCLUSIONS AND RELEVANCE

In this cohort study, longer time to AET initiation was associated with lower odds of short-term and long-term adherence to AET in Medicaid-insured patients with breast cancer. Therefore, early interventions targeting treatment initiation timelines may positively impact adherence throughout the course of treatment and, therefore, outcomes.

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.

Initiation and adherence to adjuvant endocrine therapy among urban, insured American Indian/Alaska Native breast cancer survivors

BACKGROUND

It has been shown that racial/ethnic disparities exist with regard to initiation of and adherence to adjuvant endocrine therapy (AET). However, the relationship among American Indian/Alaska Native (AIAN) individuals is poorly understood, particularly among those who reside in urban areas. We evaluated whether AET initiation and adherence were lower among AIAN individuals than those of other races/ethnicities who were enrolled in the Kaiser Permanente of Northern California (KPNC) health system.

METHODS

We identified 23,680 patients from the period 1997 to 2014 who were eligible for AET (first primary, stage I-III, hormone receptor-positive breast cancer) and used KPNC pharmacy records to identify AET prescriptions and refill dates. We assessed AET initiation (≥1 filled prescription within 1 year of diagnosis) and AET adherence (proportion of days covered ≥80%) every year up to 5 years after AET initiation.

RESULTS

At the end of the 5-year follow-up period, 83% of patients were AET initiators, and 58% were AET adherent. Compared with other races/ethnicities, AIAN women had the second-lowest rate of AET initiation (non-Hispanic Black [NHB], 78.0%; AIAN, 78.6%; Hispanic, 83.0%; non-Hispanic White [NHW], 82.5%; Asian/Pacific Islander [API], 84.7%), the lowest rate of AET adherence after 1 year and 5 years of follow-up (70.3% and 50.8%, respectively), and the greatest annual decline in AET adherence during the 4- to 5-year period of follow-up (a 13.8% decrease in AET adherence [from 64.6% to 50.8%]) after initiation of AET. In adjusted multivariable models, AIAN, Hispanic, and NHB women were less likely than NHW women to be AET adherent. At the end of the 5-year period, total underutilization (combining initiation and adherence) in AET-eligible patients was greatest among AIAN (70.6%) patients, followed by NHB (69.6%), Hispanic (63.2%), NHW (58.7%), and API (52.3%) patients, underscoring the AET treatment gap.

CONCLUSION

Our results suggest that AET initiation and adherence are particularly low for insured AIAN women.

A population-based comparison of treatment patterns, resource utilization, and costs by cancer stage for Ontario patients with hormone receptor-positive/HER2-negative breast cancer

PURPOSE

To update and expand on data related to treatment, resource utilization, and costs by cancer stage in Canadian patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer (BC).

METHODS

We analyzed data for adult women diagnosed with invasive HR+/HER2- BC between 2012 and 2016 utilizing the publicly funded health care system in Ontario. Baseline characteristics, treatment received, and health care use were descriptively compared by cancer stage (I-III vs. IV). Resource use was multiplied by unit costs for publicly funded health care services to calculate costs.

RESULTS

Our study included 21,360 patients with stage I-III plus 813 with stage IV HR+/HER2- BC. Surgery was performed on 20,510 patients with stage I-III disease (96.0%), with the majority having a lumpectomy, and radiation was received by 15,934 (74.6%). Few (n = 1601, 7.8%) received neoadjuvant and most (n = 15,655, 76.3%) received adjuvant systemic treatment. Seven hundred and fifty eight patients with metastatic disease (93.2%) received systemic therapy; 542 (66.7%) received endocrine therapy. Annual per patient health care costs were three times higher in the stage IV vs. stage I-III cohort with inpatient hospital services representing nearly 40% of total costs.

CONCLUSION

The costs associated with metastatic HR+/HER2- BC reflect a significant disease burden. Low endocrine treatment rates captured by the publicly funded system suggest guideline non-adherence or that a fair portion of Ontarian patients may be incurring out-of-pocket drug costs.

Sociodemographic, clinical, psychosocial, and healthcare-related factors associated with beliefs about adjuvant endocrine therapy among breast cancer survivors

OBJECTIVE

Adjuvant endocrine therapy (AET) reduces the risk of recurrence and mortality in women with hormone receptor-positive breast cancer. However, adherence to AET remains suboptimal. Women's beliefs about medication have been associated with medication adherence. The purpose of this study was to identify multilevel factors associated with women's beliefs about AET.

METHODS

Beliefs about AET, measured using the Belief about Medicines Questionnaire (BMQ), sociodemographic (e.g., age), psychosocial (e.g., religiosity), and healthcare factors (e.g., patient-provider communication), were collected via survey. Clinical data were abstracted from medical records. Two stepwise regression analyses models were performed to assess relationships between variables and necessity and concern beliefs.

RESULTS

In our sample of 572 women, mean BMQ concern score was 11.19 and mean necessity score was 13.85 (range 5-20). In the regression models, higher ratings of patient-provider communication were associated with lower concern and higher necessity beliefs. Higher concern beliefs were related to more AET-related symptoms (Β = 0.08; 95% CI 0.06 to 0.10; p < 0.001), lower patient satisfaction (Β = - 0.07; 95% CI - 0.09 to - 0.04; p < 0.001), and higher religiosity (Β = 0.05; 95% CI 0.01 to 0.08; p = 0.007). Higher necessity beliefs were associated with prior chemotherapy use (Β = 0.11; 95% CI 0.06 to 0.16; p < 0.005) and less education (Β = 1.00; 95% CI 0.27 to 1.73; p = 0.008).

CONCLUSIONS

Modifiable factors are related to women's AET beliefs. Healthcare interactions may play a key role with regard to shaping women's beliefs about their AET medication.

Oral Endocrine Therapy Agent, Race/Ethnicity, and Time on Therapy Predict Adherence in Breast Cancer Patients in a Large Academic Institution

INTRODUCTION

Adherence to oral endocrine therapy (OET) reduces recurrence risk for hormone receptor (HR)-positive breast cancer (BC). Refill data accessed through electronic health records may provide objective assessment of OET adherence. Our goal was to (1) determine the feasibility of reviewing electronic health records for assessing OET adherence, (2) evaluate 6 months' OET adherence in HR-positive BC patients, and (3) identify predictors of low adherence.

PATIENTS AND METHODS

A single-center, retrospective study from May through December 2018 was conducted. Primary end point was adherance rate at 6 months. Chi-square and Student t tests were used to compare adherent and nonadherent groups. Multivariable logistic regression models were used to assess predictors of adherence.

RESULTS

Of 492 patients, 338 patients were included in adherence analysis. Of 338 patients identified, 82% (n = 277) were adherent at 6 months. In the multivariable logistic model, race/ethnicity, type of endocrine therapy, and time on therapy were found to be significantly associated with adherence. Asian/non-Hispanic and white/Hispanic patients were less likely to be adherent compared to white/non-Hispanics (Asian/non-Hispanic: odds ratio [OR], 0.3; 95% confidence interval [CI], 0.11-0.82; white/Hispanic: OR, 0.27; 95% CI, 0.11-0.64). Patients prescribed aromatase inhibitors were more likely to be adherent compared to patients prescribed tamoxifen (OR, 2.06; 95% CI, 1.02-4.14). Last, patients prescribed OET for 3 to 5 years had lower adherence compared to patients given OET for 2 years or less (OR, 0.29; 95% CI, 0.09-0.91).

CONCLUSION

Accessing refill data through electronic health records was found to be feasible. Tamoxifen therapy, Asian/non-Hispanic and white/Hispanic origin, and longer time on therapy predicted nonadherence in our patients.

Racial differences in long-term adjuvant endocrine therapy adherence and mortality among Medicaid-insured breast cancer patients in Texas: Findings from TCR-Medicaid linked data

BACKGROUND

There are racial/ethnic disparities in breast cancer mortality may be attributed to differences in receipt of adjuvant cancer treatment. Our purpose was to determine whether the mortality disparities could be explained by racial/ethnic differences in long-term adherence to adjuvant endocrine therapy (AET).

METHODS

We conducted a retrospective cohort study with the Texas Cancer Registry and Medicaid claims-linked dataset of women (20-64 years) diagnosed with local and regional breast cancer who filled a prescription for AET from 2000-2008. Adherence to AET was measured at three time points (1-, 3-, and 5-year adherence) using a value for the percentage of medication filled for each period divided by the total number of possible prescriptions prescribed (Medication Possession Ratio, MPR). We created a binary variable of adherence (MPR≥80%). We performed multivariable logistic regressions to assess racial differences for the odds of AET adherence and Cox proportional hazard models to determine the risk of mortality adjusting for potential confounding variables of SES, comorbidities, tumor prognostic factors, and other cancer treatment.

RESULTS

Of the 1,497 women with breast cancer who initiated AET, 56.9%, 42.3%, and 33.3% were adherent for 1, 3, and 5-years, respectively. Hispanics compared to non-Hispanic whites did differ in the proportion that were adherent to 5-years of AET. In the adjusted analysis for long-term adherence to AET, Hispanics did not have a significantly increased risk of death compared to non-Hispanic white patients (HR: 1.13, 95% CI: 0.58-2.21). However, black compared to non-Hispanic white patients had significantly lower odds of three-year adherence (OR: 0.45, 95% CI: 0.28-0.73). After controlling for 5-year adherence to AET, the risk of death for black compared to non-Hispanic white patients was 12% lower (HR: 1.90; 95% CI: 1.03-3.51) and in the fully adjusted model, the disparity was reduced and no longer significant (OR: 1.86, 95% CI: 0.94-3.66).

CONCLUSIONS

Long-term adherence in the Medicaid population is suboptimal and racial/ethnic differences in AET adherence may partially explain disparities in mortality. This study underscores the critical need to ensure long-term adherence to AET for all racial/ethnic groups to decrease disparities in mortality.

Racial and geographic disparities in adherence and discontinuation to adjuvant endocrine therapy in Texas Medicaid-insured patients with breast cancer

The purpose of the study is to examine disparities in AET adherence and discontinuation among Texas Medicaid-insured early-stage breast cancer patients. Texas Cancer Registry Medicaid-linked database was used from 2000 to 2007 for breast cancer patients aged 20-64. Multivariable logistic regression was performed to test the association of race/ethnicity and geographic factors with AET adherence and discontinuation. Of the 1240 women with breast cancer, 60.8% of non-Hispanic white vs 46.6% of Black patients were adherent to AET in the first year. After adjusting for confounding, Black patients had lower odds of adherence compared to non-Hispanic white patients (Odds ratio 0.62, 95% CI 0.44-0.87), but they were not more likely to discontinue therapy during the study period. Patients from the Texas/Mexico border had higher odds of adherence compared to other regions (OR 2.32, 95% CI 1.29-4.18). There are substantial racial and geographic disparities in AET adherence and discontinuation among Texas Medicaid-insured women.

High Initiation of Adjuvant Hormonal Therapy Among Uninsured Stages I-III Breast Cancer Patients Treated in a Safety-Net Healthcare System

OBJECTIVE

Despite benefits of adjuvant hormonal therapy (AHT), many eligible breast cancer patients do not complete therapy as recommended. Patterns of AHT use have not been well studied among uninsured breast cancer patients who fall into coverage gaps or are ineligible for public insurance programs.

METHODS

We identified 291 patients newly diagnosed with stages I-III hormone receptor-positive breast cancer from January 2008 to December 2012. All patients were treated at a safety-net healthcare system and enrolled in an income-based medical assistance program that fills AHT prescriptions at low cost. We extracted and linked cancer registry, pharmacy claims, and medical record data to assess AHT initiation (defined as a new AHT prescription ≤18 months since diagnosis) and sociodemographic and healthcare utilization variables. Log-binomial regression was used to identify correlates of initiation.

RESULTS

Overall, 239 (82%) patients initiated AHT. Tamoxifen (42%) and anastrozole (55%) were most commonly prescribed. The mean copay was $4.90 for tamoxifen and $6.00 for anastrozole. Although crude analyses revealed small, statistically significant prevalence ratios for race/ethnicity (Hispanic vs. white, other vs. white), year of diagnosis (2008 vs. 2012), primary care visit before diagnosis (any vs. none), and smoking status (current vs. never), there were no significant correlates of initiation in the adjusted model.

CONCLUSION

Safety-net healthcare systems providing access to AHT (i.e., through reduced copays) could improve the number of eligible patients initiating therapy. Continuity and integration of care in these settings may reduce disparities frequently observed in uninsured, low-income breast cancer populations.

Barriers and facilitators of adjuvant hormone therapy adherence and persistence in women with breast cancer: a systematic review

PURPOSE

Nonadherence to hormone therapy in breast cancer survivors is common and associated with increased risk of mortality. Consistent predictors of nonadherence and nonpersistence are yet to be identified, and little research has examined psychosocial factors that may be amenable to change through intervention. This review aimed to identify predictors of nonadherence and nonpersistence to hormone therapy in breast cancer survivors in order to inform development of an intervention to increase adherence rates.

METHODS

Studies published up to April 2016 were identified through MEDLINE, Embase, Web of Science, PsycINFO, CINAHL and gray literature. Studies published in English measuring associations between adherence or persistence and any predictor variables were included. Eligible studies were assessed for methodological quality, data were extracted and a narrative synthesis was conducted.

RESULTS

Sixty-one eligible articles were identified. Most studies focused on clinical and demographic factors with inconsistent results. Some evidence suggested that receiving specialist care and social support were related to increased persistence, younger age and increased number of hospitalizations were associated with nonadherence, and good patient-physician relationship and self-efficacy for taking medication were associated with better adherence. A small amount of evidence suggested that medication beliefs were associated with adherence, but more high-quality research is needed to confirm this.

CONCLUSION

Some psychosocial variables were associated with better adherence and persistence, but the results are currently tentative. Future high-quality research should be carried out to identify psychosocial determinants of nonadherence or nonpersistence that are modifiable through intervention.

Association Between Out-Of-Pocket Costs, Race/Ethnicity, and Adjuvant Endocrine Therapy Adherence Among Medicare Patients With Breast Cancer

Purpose Previous studies suggest that adherence to adjuvant endocrine therapy (AET) for patients with breast cancer is suboptimal, especially among minorities, and is associated with out-of-pocket medication costs. This study aimed to determine whether there are racial/ethnic differences in 1-year adherence to AET and whether out-of-pocket costs explain the racial/ethnic disparities in adherence. Methods This retrospective cohort study used the SEER-Medicare linked database to identify patients ≥ 65 years of age with hormone receptor-positive breast cancer who were enrolled in Medicare Part D from 2007 to 2009. The cohort included non-Hispanic whites, blacks, Hispanics, and Asians. Out-of-pocket costs for AET medications were standardized for a 30-day supply. Adherence to tamoxifen, aromatase inhibitors (AIs), and overall AET (tamoxifen or AIs) was assessed using the medication possession ratio (≥ 80%) during the 12-month period. Results Of 8,688 patients, 3,197 (36.8%) were nonadherent to AET. Out-of-pocket costs for AET medication were associated with lower adjusted odds of adherence for all four cost categories compared with the lowest category of ≤ $2.65 ( P < .01). In the univariable analysis, Hispanics had higher odds of adherence to any AET at initiation (OR, 1.30; 95% CI, 1.07 to 1.57), and blacks had higher odds of adherence to AIs at initiation (OR, 1.27; 95% CI, 1.04 to 1.54) compared with non-Hispanic whites. After adjusting for copayments, poverty status, and comorbidities, the association was no longer significant for Hispanics (OR, 0.95; 95% CI, 0.78 to 1.17) or blacks (OR, 0.96; 95% CI, 0.77 to 1.19). Blacks had significantly lower adjusted odds of adherence than non-Hispanic whites when they initiated AET therapy with tamoxifen (OR, 0.54; 95% CI, 0.31 to 0.93) after adjusting for socioeconomic, clinic, and prognostic factors. Conclusion Racial/ethnic disparities in AET adherence were largely explained by women's differences in socioeconomic status and out-of-pocket medication costs.

Medicare D Subsidies and Racial Disparities in Persistence and Adherence With Hormonal Therapy

Purpose To investigate the role of out-of-pocket cost supports through the Medicare Part D Low-Income Subsidy on disparities in breast cancer hormonal therapy persistence and adherence by race or ethnicity. Methods A nationwide cohort of women age ≥ 65 years with a breast cancer operation between 2006 and 2007 and at least one prescription filled for oral breast cancer hormonal therapy was identified from all Medicare D enrollees. The association of race or ethnicity with nonpersistence (90 consecutive days with no claims for a hormonal therapy prescription) and nonadherence (medication possession rate < 80%) was examined. Survival analyses were used to account for potential differences in age, comorbidity, or intensity of other treatments. Results Among the 25,111 women in the study sample, 77% of the Hispanic and 70% of the black women received a subsidy compared with 21% of the white women. By 2 years, 69% of black and 70% of Hispanic patients were persistent compared with 61% of white patients. In adjusted analyses, patients in all three unsubsidized race or ethnicity groups had greater discontinuation than subsidized groups (white patients: hazard ratio [HR], 1.83; 95% CI, 1.70 to 1.95; black patients: HR, 2.09; 95% CI, 1.73 to 2.51; Hispanic patients: HR, 3.00; 95% CI, 2.37 to 3.89). Racial or ethnic persistence disparities that were present for unsubsidized patients were not present or reversed among subsidized patients. All three subsidized race or ethnicity groups also had higher adherence than all three unsubsidized groups, although with the smallest difference occurring in black women. Conclusion Receipt of a prescription subsidy was associated with substantially improved persistence to breast cancer hormonal therapy among white, black, and Hispanic women and lack of racial or ethnic disparities in persistence. Given high subsidy enrollment among black and Hispanic women, policies targeted at low-income patients have the potential to also substantially reduce racial and ethnic disparities.

Racial differences in receipt of adjuvant hormonal therapy among Medicaid enrollees in South Carolina diagnosed with breast cancer

Several factors contribute to the pervasive Black-White disparity in breast cancer mortality in the U.S., such as tumor biology, access to care, and treatments received including adjuvant hormonal therapy (AHT), which significantly improves survival for hormone receptor-positive breast cancers (HR+). We analyzed South Carolina Central Cancer Registry-Medicaid linked data to determine if, in an equal access health care system, racial differences in the receipt of AHT exist. We evaluated 494 study-eligible, Black (n = 255) and White women (n = 269) who were under 65 years old and diagnosed with stages I-III, HR+ breast cancers between 2004 and 2007. Bivariate and multivariate analyses were conducted to assess receipt of ≥1 AHT prescriptions at any point in time following (ever-use) or within 12 months of (early-use) breast cancer diagnosis. Seventy-two percent of the participants were ever-users (70 % Black, 74 % White) and 68 % were early-users (65 % Black, 71 % White) of AHT. Neither ever-use (adjusted OR (AOR) = 0.75, 95 % CI 0.48-1.17) nor early-use (AOR = 0.70, 95 % CI 0.46-1.06) of AHT differed by race. However, receipt of other breast cancer-specific treatments was independently associated with ever-use and early-use of AHT [ever-use: receipt of surgery (AOR = 2.15, 95 % CI 1.35-3.44); chemotherapy (AOR = 1.97, 95 % CI 1.22-3.20); radiation (AOR = 2.33, 95 % CI 1.50-3.63); early-use: receipt of surgery (AOR = 2.03, 95 % CI 1.30-3.17); chemotherapy (AOR = 1.90, 95 % CI 1.20-3.03); radiation (AOR = 1.73, 95 % CI 1.14-2.63)]. No racial variations in use of AHT among women with HR+ breast cancers insured by Medicaid in South Carolina were identified, but overall rates of AHT use by these women is low. Strategies to improve overall use of AHT should include targeting breast cancer patients who do not receive adjuvant chemotherapy and/or radiation.

Breast Cancer and Menopausal Hormone Therapy by Race/Ethnicity and Body Mass Index

In analyses combining estrogen with or without progestin, some observational studies describe minimal breast cancer risk in obese and black women. Therefore, we examined these suggested interactions in the two Women's Health Initiative (WHI) randomized hormone therapy trials. The estrogen plus progestin trial entered 16 608 postmenopausal women with a uterus, while the estrogen trial entered 10 736 postmenopausal women with prior hysterectomy. Hazard ratios (HRs), 95% confidence intervals (CIs), and P values from log-rank x(2) statistics were estimated from Cox proportional hazards models with subgroup analyses based on tests of interaction. All statistical tests were two-sided. Estrogen plus progestin statistically significantly increased breast cancer incidence (HR = 1.28, 95% CI = 1.11 to 1.48, P < .001), with hazard ratios greater than 1 in all body mass index (BMI) subgroups (P interaction = .58) and hazard ratios greater than 1 in black and white women (P interaction = .96). In contrast, estrogen alone statistically significantly decreased breast cancer incidence (HR = 0.79, 95% CI = 0.65 to 0.90, P = .02), with hazard ratios lower than 1 in all BMI subgroups (P interaction = .86) and hazard ratios lower than 1 in black and white women, where analyses with limited numbers suggest somewhat greater reduction in black women (P interaction = .09). In summary, estrogen plus progestin and estrogen alone have opposite effects on breast cancer incidence, with no statistically significant interactions by race/ethnicity or BMI. Therefore, observational studies should not combine these two regimens when examining breast cancer risk.

Ethnic differences in initiation and timing of adjuvant endocrine therapy among older women with hormone receptor-positive breast cancer enrolled in Medicare Part D

The aim of this study was to determine whether there are racial/ethnic differences in initiation and timing of adjuvant endocrine therapy (AET) after Medicare Part D drug coverage. We conducted a retrospective cohort study using data from the Surveillance, Epidemiology, and End Results-Medicare-linked data to assess ethnic, socio-demographic, and tumor characteristic variations in the initiation of AET among patients ≥65 with hormone receptor-positive breast cancer in 2007-2009 enrolled in Medicare Part D through 2010. Logistic regression models were performed to assess the association between race/ethnicity and the initiation of tamoxifen, aromatase inhibitors (AIs), and overall AET (tamoxifen or AIs) within the first 12 months of diagnosis. Of the 12,198 women with hormone receptor-positive breast cancer, 74.8 % received AET within 12 months of diagnosis, of which 17.3 % received tamoxifen and 82.8 % received AIs. After controlling for all variables, only Asian women were found to have a greater odds of initiation of overall AET compared to non-Hispanic white women (odds ratio (OR): 1.28, 95 % CI: 1.03-1.58). Hispanic Mexicans and non-Hispanic black patients had a significantly lower odds of tamoxifen initiation (0.70, 0.54-0.91; 0.25, 0.10-0.62). For AI initiation, Hispanic Mexicans and Asians had a higher odds compared to non-Hispanic white women (2.06, 1.34-3.10; 1.33, 1.11-1.61). A suboptimal proportion of women (25.2 %) did not initiate AET within 12 months of diagnosis and therefore did not receive the full benefits of treatment to reduce the risk of breast cancer recurrence and mortality. Racial/ethnic differences in the initiation of tamoxifen and AIs have important implications that require further investigation.

Breast Cancer Mortality in African-American and Non-Hispanic White Women by Molecular Subtype and Stage at Diagnosis: A Population-Based Study

BACKGROUND

Higher breast cancer mortality rates for African-American than non-Hispanic White women are well documented; however, it remains uncertain if this disparity occurs in disease subgroups defined by tumor molecular markers and stage at diagnosis. We examined racial differences in outcome according to subtype and stage in a diverse, population-based series of 103,498 patients.

METHODS

We obtained data for all invasive breast cancers diagnosed between January 1, 2005, and December 31, 2012, and followed through December 31, 2012, among 93,760 non-Hispanic White and 9,738 African-American women in California. Molecular subtypes were categorized according to tumor expression of hormone receptor (HR, based on estrogen and progesterone receptors) and human epidermal growth factor receptor 2 (HER2). Cox proportional hazards models were used to calculate relative hazard (RH) and 95% confidence intervals (CI) for breast cancer-specific mortality.

RESULTS

After adjustment for patient, tumor, and treatment characteristics, outcomes were comparable by race for stage I or IV cancer regardless of subtype, and HR(+)/HER2(+) or HR(-)/HER2(+) cancer regardless of stage. We found substantially higher hazards of breast cancer death among African-American women with stage II/III HR(+)/HER2(-) (RH, 1.31; 95% CI, 1.03-1.65; and RH, 1.39; 95% CI, 1.10-1.75, respectively) and stage III triple-negative cancers relative to Whites.

CONCLUSIONS

There are substantial racial/ethnic disparities among patients with stages II/III HR(+)/HER2(-) and stage III triple-negative breast cancers but not for other subtype and stage.

IMPACT

These data provide insights to assess barriers to targeted treatment (e.g., trastuzumab or endocrine therapy) of particular subtypes of breast cancer among African-American patients.

Identifying the determinants of adjuvant hormonal therapy medication taking behaviour in women with stages I-III breast cancer: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to identify the modifiable determinants of adjuvant hormonal therapy medication taking behaviour (MTB) in women with stage I-III breast cancer in clinical practice settings.

METHODS

We searched PubMed EMBASE, PsycINFO and CINAHL for articles investigating determinants of adjuvant hormonal therapy. Potentially modifiable determinants were identified and mapped to the 14 domains of the Theoretical Domains Framework (TDF), an integrative framework of theories of behavioural change. Meta-analysis was used to calculate pooled odds ratios for selected determinants.

RESULTS

Potentially modifiable determinants were identified in 42 studies and mapped to 9 TDF domains. In meta-analysis treatment side-effects (Domain: Beliefs about Capabilities) and follow-up care with a general practitioner (vs. oncologist) (Social Influences) were significantly negatively associated with persistence (p<0.001) and number of medications (Behaviour Regulation) was significantly positively associated with persistence (p<0.003). Studies did not examine several domains (including Beliefs about Consequences, Intentions, Goals, Social Identity, Emotion and Knowledge) which have been reported to influence MTB in other disease groups.

CONCLUSIONS

There is some evidence that the domains Beliefs about Capabilities, Behaviour Regulation and Social Influences influence hormonal therapy MTB.

PRACTICE IMPLICATIONS

Further research is needed to develop effective interventions to improve hormonal therapy MTB.

Racial and Ethnic Differences in Breast Cancer Survival: Mediating Effect of Tumor Characteristics and Sociodemographic and Treatment Factors

PURPOSE

To evaluate the relationship between race/ethnicity and breast cancer-specific survival according to subtype and explore mediating factors.

PATIENTS AND METHODS

Participants were women presenting with stage I to III breast cancer between January 2000 and December 2007 at National Comprehensive Cancer Network centers with survival follow-up through December 2009. Cox proportional hazards regression was used to compare breast cancer-specific survival among Asians (n = 533), Hispanics (n = 1,122), and blacks (n = 1,345) with that among whites (n = 14,268), overall and stratified by subtype (luminal A like, luminal B like, human epidermal growth factor receptor 2 type, and triple negative). Model estimates were used to derive mediation proportion and 95% CI for selected risk factors.

RESULTS

In multivariable adjusted models, overall, blacks had 21% higher risk of breast cancer-specific death (hazard ratio [HR], 1.21; 95% CI, 1.00 to 1.45). For estrogen receptor-positive tumors, black and white survival differences were greatest within 2 years of diagnosis (years 0 to 2: HR, 2.65; 95% CI, 1.34 to 5.24; year 2 to end of follow-up: HR, 1.50; 95% CI, 1.12 to 2.00). Blacks were 76% and 56% more likely to die as a result of luminal A-like and luminal B-like tumors, respectively. No disparities were observed for triple-negative or human epidermal growth factor receptor 2-type tumors. Asians and Hispanics were less likely to die as a result of breast cancer compared with whites (Asians: HR, 0.56; 95% CI, 0.37 to 0.85; Hispanics: HR, 0.74; 95% CI, 0.58 to 0.95). For blacks, tumor characteristics and stage at diagnosis were significant disparity mediators. Body mass index was an important mediator for blacks and Asians.

CONCLUSION

Racial disparities in breast cancer survival vary by tumor subtype. Interventions are needed to reduce disparities, particularly in the first 2 years after diagnosis among black women with estrogen receptor-positive tumors.

Racial/Ethnic and socioeconomic disparities in endocrine therapy adherence in breast cancer: a systematic review

We examined the current literature to understand factors that influence endocrine therapy (ET) adherence among racial/ethnic and socioeconomic subpopulations of breast cancer patients. We searched PubMed and PsycINFO databases for studies from January 1, 1978, to June 20, 2014, and January 1, 1991, to June 20, 2014, respectively, and hand-searched articles from relevant literature reviews. We abstracted and synthesized results within a social ecological framework. Fourteen articles met all inclusion criteria. The majority of included articles reported significant underuse of ET among minority and low-income women. Modifiable intrapersonal, interpersonal, and community-level factors are associated with ET use, and these factors vary across subgroups. Both race/ethnicity and socioeconomic status are associated with ET use in most settings. Variation in factors associated with ET use across subgroups indicates the need for more nuanced research and targeted interventions among breast cancer patients.

Trends in 5-year survival rates among breast cancer patients by hormone receptor status and stage

Improvement in breast cancer survival has been observed in recent decades in the U.S., but it is unclear if similar survival gains are consistent across breast cancer subtypes, especially with regards to more advanced stages of the disease. Data were from 13 population-based cancer registries participating in the surveillance, epidemiology, and end results (SEER) program, consisting of women between 20 and 79 years of age diagnosed with invasive breast cancer between 1992 and 2008. 2-year (1992-2008) and 5-year (1992-2006) breast cancer cause-specific survival rates were calculated and stratified by estrogen receptor (ER)/progesterone receptor (PR) status, stage, and race. Annual percent changes in survival rates were assessed. From 1992 through 1998-1999, 5- and 2-year cause-specific survival rates significantly improved across ER+/PR+, ER-/PR-, and ER+/PR- subtypes, with an annual increase ranging from 0.5 to 1.0 % in the 5-year rates. From 1998-1999 to 2006, different patterns were observed by ER/PR subtypes with survival rates slightly improving for ER+/PR+, continuing to improve at a rate of 0.5 % per year for ER-/PR-, and dropping 0.3 % annually for ER+/PR-. No significant survival gains were experienced by patients with ER-/PR+ cancer during the study period. In terms of advanced diseases, greatest annual increases in survival rates were seen for patients with stage III-IV ER+/PR+ and ER-/PR- tumors but less progress was observed for advanced ER+/PR- breast cancers. Steady improvements in survival rates for breast cancer have been achieved over the past several decades. However, 5-year survival rates for stage IV disease remained dismally below 20 % for most ER/PR subtypes.

Racial disparities in initiation of adjuvant endocrine therapy of early breast cancer

Endocrine therapy (ET) is the cornerstone of adjuvant therapy for hormone-receptor positive (HR+) breast cancer. The survival gap between African-American (AA) and white women with breast cancer is most pronounced in HR+ subtypes, and could be related to differences in ET use. The relationship between race and initiation of ET is not well defined. We investigated patterns of ET initiation by race in a diverse cohort of women covered by commercial health insurance. We identified 2,640 women with incident HR+ breast cancer in the North Carolina Central Cancer Registry whose records linked to commercial insurance claims using the Integrated Cancer Information and Surveillance System (ICISS) database. The sample included women age <65 years diagnosed with stage I-III HR+ cancers between 2004 and 2009. We used multivariate Poisson regression to examine the effect of race on likelihood of initiating ET. 14 % of women did not initiate ET within 12 months of diagnosis. AA women were 17 % less likely to initiate ET than whites (aRR 0.83, 95 % CI 0.74-0.93). When analyzed by subset, racial disparities persisted among women who received chemotherapy (aHR 0.67, 95 % CI 0.56-0.80) but not among women who did not receive chemotherapy (aHR 0.96, 95 % CI 0.76-1.21). AA women in our sample were less likely to initiate ET than whites, and this disparity was concentrated among chemotherapy-treated women. ET under-utilization may contribute to the racial survival gap in HR+ breast cancer, and represents an opportunity for intervention to reduce breast cancer disparities.

Adherence to endocrine therapy in breast cancer adjuvant and prevention settings

Adherence to oral endocrine therapy in adjuvant breast cancer settings is a substantial clinical problem. To provide current perspective on adherence to oral endocrine therapies, a comprehensive literature review was conducted. In adjuvant trials, endocrine therapy adherence is relatively high with greater adherence for aromatase inhibitors compared with tamoxifen. In contrast, adherence to adjuvant therapy in clinical practice is relatively poor, with only about 50% of women successfully completing 5-year therapy. Importantly, good adherence (>80% use) has been associated with lower recurrence risk. Endocrine therapy adherence in primary breast cancer prevention trials parallels that seen in adjuvant trials. Factors associated with nonadherence include low recurrence risk perception, side effects, age extremes, medication cost, suboptimal patient-physician communication, and lack of social support. Few prospective studies have evaluated interventions designed to improve adherence. Interventions currently proposed reflect inferences from clinical trial procedures in which clinical contacts are commonly greater than in usual practice settings. In conclusion, for optimal breast cancer outcome, adherence to endocrine therapy must improve. Although general recommendations likely to improve adherence can be made based on clinical trial results and preliminary prospective trial findings, research specifically targeting this issue is needed to establish effective intervention strategies.