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

Racial Disparity in Adherence to Endocrine Therapy among Women with Early-Stage Hormone Receptor Positive Breast Cancer: An Analysis of Arkansas All-Payers Claims Database

INTRODUCTION/BACKGROUND

To assess racial/ethnic disparities in endocrine therapy (ET) adherence among women with breast cancer.

MATERIALS AND METHODS

A retrospective cohort study of Arkansas All-Payer Claims Database (APCD) linked to Arkansas Cancer Registry (ACR). Women with stages 0-3 HR+ breast cancer diagnosed in 2013-2017 were followed from cancer diagnosis for a year to determine ET initiation. Among women who initiated ETs within 1 year of diagnosis, we assessed first-year compliance (proportion of days covered ≥ 0.8) and followed them for 5 years, censoring at death, end of data availability (December 21, 2019), or disenrollment from insurance coverage, whichever occurred first, to determine time to discontinuation. Regression analysis was conducted to determine racial/ethnic disparities in ET use adjusting for patients demographic, clinical, tumor characteristics and county-level socioeconomic factors.

RESULTS

Among women with continuous insurance coverage, 81% initiated ET within 1 year of diagnosis; 80% were compliant in the first year of ET use and 27.4% discontinued ET by year 5 among those who initiated ET in the first year. There were no racial/ethnic differences in ET initiation or first-year compliance adjusting for covariates. NHB women were significantly less likely to discontinue ET within 5 years after ET initiation compared to NHW women after (HR, 95% CI, 0.76, 0.58-0.98; P = .035).

CONCLUSION

After adjusting for patients' and tumor characteristics, there were no racial/ethnic differences in ET initiation within 1 year of diagnosis and ET compliance within first year of ET use. However, NHB women were less likely to discontinue ET within 5 years of initiation.

Racial Differences in Breast Cancer Survival Between Black and White Women According to Tumor Subtype: A Systematic Review and Meta-Analysis

PURPOSE

Despite effective early-detection approaches and innovative treatments, Black women in the United States have higher breast cancer mortality rates compared with White women. The purpose of this systematic review and meta-analysis is to determine the extent of disparities in breast cancer survival between Black and White women according to tumor subtype.

METHODS

A comprehensive database search was performed for full-text, English-language articles published from January 1, 2000, to December 31, 2022. Included studies compared survival between Black and White female patients with breast cancer within subtypes defined by hormone receptor and human epidermal growth factor receptor 2 (HER2)/neu (HER2; now known as ERBB2) status. Random-effects models were used to combine study-specific results and generate pooled relative risks (RRs) and 95% CIs for breast cancer-specific or overall survival (OS). A protocol for this review was registered in PROSPERO (CRD42021268212).

RESULTS

Eighteen studies including 228,885 (34,262 Black; 182,466 White) patients with breast cancer were identified. Compared with White women, Black women had a higher risk of breast cancer death for all tumor subtypes. The summary risk of breast cancer death was 50% higher among hormone receptor-positive HER2-negative [HER2-] tumors (RR, 1.50 [95% CI, 1.30 to 1.72]), 34% higher for hormone receptor+/HER2+ (RR, 1.34 [95% CI, 1.10 to 1.64]), 20% higher for hormone receptor-negative (-)/HER2+ (RR, 1.29 [95% CI, 1.00 to 1.43]), and 17% higher among individuals with hormone receptor-/HER2- tumors (hazard ratio, 1.17; 95% CI, 1.10 to 1.25). Black women also had poorer OS than White women for all subtypes.

CONCLUSION

These results suggest there are both subtype-specific and subtype-independent mechanisms that contribute to disparities in breast cancer survival between Black and White women, which require multilevel interventions to address and achieve health equity.

Endocrine therapy initiation among women diagnosed with ductal carcinoma in situ from 2001 to 2018

PURPOSE

Trials demonstrating benefits of tamoxifen for women with ductal carcinoma in situ (DCIS) were published > 20 years ago; yet subsequent uptake of endocrine therapy was low. We estimated endocrine therapy initiation in women with DCIS between 2001 and 2018 in a community setting, reflecting more recent years of diagnosis than previous studies.

METHODS

This retrospective cohort included adult females ≥ 20 years diagnosed with first primary DCIS between 2001 and 2018, followed through 2019, and enrolled in one of three U.S. integrated healthcare systems. We collected data on endocrine therapy dispensings (tamoxifen, aromatase inhibitors [AIs]) from electronic pharmacy records within 12 months after DCIS diagnosis. Using generalized linear models with a log link and Poisson distribution, we estimated endocrine therapy initiation rates over time and by patient, tumor (including estrogen receptor [ER] status), and treatment characteristics.

RESULTS

Among 2020 women with DCIS, 587 (29%) initiated endocrine therapy within 12 months after diagnosis (36% among 1208 women with ER-positive DCIS). Among women who used endocrine therapy, 506 (86%) initiated tamoxifen and 81 (14%) initiated AIs. Age-adjusted endocrine therapy initiation declined from 34 to 21% between 2001 and 2017; between 2015 and 2018, AI use increased from 8 to 35%. Women less likely to initiate endocrine therapy were ER-negative or had borderline/unknown or no ER test results, ≥ 65 years at diagnosis, Black, and received no radiotherapy.

CONCLUSION

One-third of women diagnosed with DCIS initiated endocrine therapy, and use decreased over time. Understanding why women eligible for endocrine therapy do not initiate is important to maximizing disease-free survival following DCIS diagnosis.

Incident Cardiovascular Disease Risk among Older Asian, Native Hawaiian and Pacific Islander Breast Cancer Survivors

BACKGROUND

Cardiotoxicity among breast cancer survivors is associated with chemotherapy and radiation therapy. The risk of cardiovascular disease (CVD) among Asian, Native Hawaiian and Pacific Islander (ANHPI) breast cancer survivors in the United States is unknown.

METHODS

We used the SEER-Medicare linked database to estimate the risk of CVD among older breast cancer survivors. International Classification of Disease diagnosis codes were used to identify incident CVD outcomes. Cox proportional hazards models were used to estimate HRs and 95% confidence intervals (CI) comparing ANHPI with Non-Hispanic White (NHW) patients with breast cancer for CVD, and among ANHPI race and ethnicity groups.

RESULTS

A total of 7,122 ANHPI breast cancer survivors and 21,365 NHW breast cancer survivors were identified. The risks of incident heart failure and ischemic heart disease were lower among ANHPI compared with NHW breast cancer survivors (HRheart failure, 0.72; 95% CI, 0.61-0.84; HRheart disease, 0.74; 95% CI, 0.63-0.88). Compared with Japanese patients with breast cancer, Filipino, Asian Indian and Pakistani, and Native Hawaiian breast cancer survivors had higher risks of heart failure. ischemic heart disease and death. Among ANHPI breast cancer survivors, risk factors for heart failure included older age, higher comorbidity score, distant cancer stage and chemotherapy.

CONCLUSIONS

Our results support heterogeneity in CVD outcomes among breast cancer survivors among ANHPI race and ethnicity groups. Further research is needed to elucidate the disparities experienced among ANHPI breast cancer survivors.

IMPACT

Filipino, Asian Indian and Pakistani, and Native Hawaiian patients with breast cancer had higher risks of heart failure, ischemic heart disease and death among ANHPI patients with breast cancer.

Survival Disparities in US Black Compared to White Women with Hormone Receptor Positive-HER2 Negative Breast Cancer

Black women in the US have significantly higher breast cancer mortality than White women. Within biomarker-defined tumor subtypes, disparate outcomes seem to be limited to women with hormone receptor positive and HER2 negative (HR+/HER2-) breast cancer, a subtype usually associated with favorable prognosis. In this review, we present data from an array of studies that demonstrate significantly higher mortality in Black compared to White women with HR+/HER2-breast cancer and contrast these data to studies from integrated healthcare systems that failed to find survival differences. Then, we describe factors, both biological and non-biological, that may contribute to disparate survival in Black women.

Age and Racial Disparities in the Utilization of Anticancer, Antihypertension, and Anti-diabetes Therapies, and in Mortality in a Large Population-Based Cohort of Older Women with Breast Cancer

OBJECTIVE

This study examined the receipt of therapies for cancer, hypertension, and diabetes in association with age and racial disparities in mortality among women with breast cancer.

METHODS

This study identified 92,829 women diagnosed with breast cancer at age ≥ 65 years in 2007-2015 with follow-up to 2016 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database.

RESULTS

There were substantial age and racial disparities in the prevalence of hypertension and diabetes, which was higher in women ≥ 75 (86.3% and 32.0%) than younger women 65-74 (72.8% and 29.3%), and the highest in Black women (91.1% and 49.1%), followed by Asian women (80.2% and 40.5%), and White women (77.6 and 27.8%). Black women were significantly less likely to receive chemotherapy (odds ratio: 0.70, 95% CI: 0.64-0.75), radiation therapy (0.87, 0.83-0.92), and hormone therapy (0.80, 0.76-0.85), but significantly more likely to receive antihypertensive (1.26, 1.19-1.33) and antidiabetic (1.19, 1.10-1.28) drugs than White women, after adjusting for sociodemographic and tumor factors. As compared to White women, Black women had a significantly higher risk of all-cause mortality (1.46, 1.41-1.52), but it became insignificant after adjusting for treatment factors (1.01, 0.97-1.06), whereas the adjusted risk of breast cancer-specific mortality remained significantly higher (1.08, 1.01-1.15) in Black women; Asian and other ethnic women had a significantly lower risk of all-cause and breast cancer-specific mortality.

CONCLUSIONS

There were substantial age and racial disparities in the prevalence of hypertension and diabetes and in the receipt of medications. Black women did not have a significantly higher risk of all-cause mortality but had a significantly higher risk of breast cancer-specific mortality as compared to White women.

Accuracy of tumor registry versus pharmacy dispensings for breast cancer adjuvant endocrine therapy

PURPOSE

Accounting for endocrine therapy use for breast cancer treatment is important for studies of survivorship. We evaluated the accuracy of Surveillance, Epidemiology, and End Results (SEER) breast cancer endocrine therapy data compared with pharmacy dispensings from an integrated health system.

METHODS

We included women with non-metastatic hormone receptor positive primary breast cancer diagnosed between 1995 and 2017 enrolled in Kaiser Permanente Washington, linking their data with SEER. We used pharmacy dispensings for endocrine therapy within one year following diagnosis as our reference standard. We calculated kappa (concordance), positive predictive value (PPV), and negative predictive values (NPV) overall and stratified by woman and tumor characteristics of interest.

RESULTS

Of 5,055 women, mean age at diagnosis was 62 years (interquartile range = 53-71); 53% had localized stage, 56% received lumpectomy with radiation, and 31% received chemotherapy. SEER data alone identified 67% of women as having received endocrine therapy; this increased to 75% with pharmacy dispensings. SEER's concordance with pharmacy dispensings was 0.68 (PPV = 91%; NPV = 76%). PPV did not vary by tumor or women characteristics; however, NPV declined with younger age at diagnosis (64% in < 45 years vs. 86% in 75+ years), increasing tumor stage (49% in regional stage vs. 91% in DCIS), and chemotherapy treatment (41% in those with chemotherapy vs. 83% in those without chemotherapy).

CONCLUSION

Pharmacy dispensings enable more complete endocrine therapy capture, particularly in women with more advanced tumors or who receive chemotherapy. We determined woman, tumor, and treatment characteristics that contribute to underascertainment of endocrine therapy use in tumor registries.

Endocrine therapy initiation among women with stage I-III invasive, hormone receptor-positive breast cancer from 2001-2016

PURPOSE

This retrospective cohort study examined patterns of endocrine therapy initiation over time and by demographic, tumor, and treatment characteristics.

METHODS

We included 7777 women from three U.S. integrated healthcare systems diagnosed with incident stage I-III hormone receptor-positive breast cancer between 2001 and 2016. We extracted endocrine therapy from pharmacy dispensings, defining initiation as dispensings within 12 months of diagnosis. Demographic, tumor, and treatment characteristics were collected from electronic health records. Using generalized linear models with a log link and Poisson distribution, we estimated initiation of any endocrine therapy, tamoxifen, and aromatase inhibitors (AI) over time with relative risks (RR) and 95% confidence intervals (CI) adjusted for age, tumor characteristics, diagnosis year, other treatment, and study site.

RESULTS

Among women aged 20+ (mean 62 years), 6329 (81.4%) initiated any endocrine therapy, and 1448 (18.6%) did not initiate endocrine therapy. Tamoxifen initiation declined from 67 to 15% between 2001 and 2016. AI initiation increased from 6 to 69% between 2001 and 2016 in women aged ≥ 55 years. The proportion of women who did not initiate endocrine therapy decreased from 19 to 12% between 2002 and 2014 then increased to 17% by 2016. After adjustment, women least likely to initiate endocrine therapy were older (RR = 0.81, 95% CI 0.77-0.85 for age 75+ vs. 55-64), Black (RR = 0.93, 95% CI 0.87-1.00 vs. white), and had stage I disease (RR = 0.88, 95% CI 0.85-0.91 vs. stage III).

CONCLUSIONS

Despite an increase in AI use over time, at least one in six eligible women did not initiate endocrine therapy, highlighting opportunities for improving endocrine therapy uptake in breast cancer survivors.

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.

Patient Characteristics and Outcomes of Nonmetastatic Breast Cancer in Haiti: Results from a Retrospective Cohort

BACKGROUND

There are few studies on breast cancer outcomes in the Caribbean region. This study identified a retrospective cohort of female patients with nonmetastatic breast cancer in Haiti and conducted survival analyses to identify prognostic factors that may affect patient outcomes.

METHODS

The cohort included 341 patients presenting between June 2012 and December 2016. The primary endpoint was event-free survival (EFS), defined as time to disease progression, recurrence, or death. Descriptive summaries of patient characteristics and treatments were reported. Survival curves were plotted using Kaplan-Meier estimation. Multivariate survival analyses were performed using Cox proportional hazards regression.

RESULTS

Median age at diagnosis was 49 years, with 64.2% being premenopausal. Most patients (55.1%) were staged as locally advanced. One hundred and sixty patients received neoadjuvant therapy: 33.3% of patients with early stage disease and 61.2% of those with locally advanced stage disease. Curative-intent surgery was performed in 278 (81.5%) patients, and 225 patients received adjuvant therapy. Adjuvant endocrine therapy was used in 82.0% of patients with estrogen receptor-positive disease. During the follow-up period, 28 patients died, 77 had disease recurrence, and 10 had progressive disease. EFS rates at 2 years and 3 years were 80.9% and 63.4%, respectively. After controlling for multiple confounders, the locally advanced stage group had a statistically significant adjusted hazard ratio for EFS of 3.27 compared with early stage.

CONCLUSION

Patients with nonmetastatic breast cancer in Haiti have more advanced disease, poorer prognostic factors, and worse outcomes compared with patients in high-income countries. Despite several limitations, curative treatment is possible in Haiti.

IMPLICATIONS FOR PRACTICE

Patients with breast cancer in Haiti have poor outcomes. Prior studies show that most Haitian patients are diagnosed at later stages. However, there are no rigorous studies describing how late-stage diagnosis and other prognostic factors affect outcomes in this population. This study presents a detailed analysis of survival outcomes and assessment of prognostic factors in patients with nonmetastatic breast cancer treated in Haiti. In addition to late-stage diagnosis, other unfavorable prognostic factors identified were young age and estrogen receptor-negative disease. The study also highlights that the availability of basic breast cancer treatment in Haiti can lead to promising early patient outcomes.

The impact of the introduction of generic aromatase inhibitors on adherence to hormonal therapy over the full course of 5-year treatment for breast cancer

BACKGROUND

High out-of-pocket costs (OOPCs) often are found to be inversely associated with adherence to medical treatment. The introduction of generic aromatase inhibitors (GAIs) significantly reduced the OOPCs of patients. The objective of the current study was to explore the impact of the introduction of GAIs on adjuvant hormone therapy (AHT) adherence over the full course of breast cancer treatment.

METHODS

Women aged ≥65 years who were diagnosed with hormone receptor-positive breast cancer from 2007 through mid-2009 were identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database. Multivariate logistic regression was used to estimate the likelihood of AHT initiation and an interrupted time series model was used to predict the association between the introduction of GAIs and AHT adherence. The model was stratified further using Medicare low-income subsidy (LIS) status.

RESULTS

A total of 10,905 women were included, approximately 62.8% of whom initiated AHT within the first year of their breast cancer diagnosis. Adjusted adherence among LIS beneficiaries was 11.4% higher than among non-LIS beneficiaries (P < .001). Non-LIS beneficiaries had an overall decreasing trend of adherence (-0.035; P < .001) prior to the introduction of GAIs. They experienced a 3.4% increase in the slope 6 months after the first GAI, anastrozole, entered the market, and an additional 0.8% increase in the slope 6 months after letrozole and exemestane were introduced (P < .001). Adherence change among LIS patients was small and statistically insignificant.

CONCLUSIONS

With the introduction of GAIs, the decrease trend of adherence to therapy atteunated over the course of treatment. Although the successful implementation of the Medicare LIS program minimized the OOPCs for financially vulnerable patients, policymakers should be cautious not to introduce disparities for those who may be of low income but ineligible for such a program.

Breast Cancer Health Disparities in Hispanics/Latinas

Purpose of the review

Breast cancer incidence and mortality rates are lower in some Hispanic/Latino subpopulations compared to Non-Hispanic White women. However, studies suggest that the risk of breast cancer-specific mortality is higher in US Hispanics/Latinas. In this review we summarized current knowledge on factors associated with breast cancer incidence and risk of mortality in women of Hispanic/Latino origin.

Recent findings

Associative studies have proposed a multiplicity of factors likely contributing to differences in breast cancer incidence and survival between population groups, including socioeconomic/sociodemographic factors, lifestyle choices as well as access to and quality of care. Reports of association between global genetic ancestry overall as well as subtype-specific breast cancer risk among Hispanic/Latinas suggest that incidence and subtype distribution could result from differential exposure to environmental and lifestyle related factors correlated with genetic ancestry as well as germline genetic variation.

Summary

Hispanic/Latino in the United States have been largely underrepresented in cancer research. It is important to implement inclusive programs that facilitate the access of this population to health services and that also include education programs for the community on the importance of screening. In addition, it is important to continue promoting the inclusion of Hispanics/Latinos in genomic studies that allow understanding the biological behavior of this disease in the context of all human genetic diversity.

Why individual-level interventions are not enough: Systems-level determinants of oral anticancer medication adherence

Nonadherence to oral anticancer medications (OAMs) in the United States is as low as 33% for some cancers. The reasons for nonadherence to these lifesaving medications are multifactorial, yet the majority of studies focus on patient-level factors influencing uptake and adherence. Individually based interventions to increase patient adherence have not been effective, and this warrants attention to factors at the payor, pharmaceutical, and clinical systems levels. Based on the authors' research and clinical experiences, this commentary brings fresh attention to the long-standing issue of OAM nonadherence, a growing quality-of-care issue, from a systems perspective. In this commentary, the key driving factors in pharmaceutical and payor systems (state and federal laws, payor/insurance companies, and pharmaceutical companies), clinical systems (hospitals and providers), and patient contexts that have trickle-down effects on patient adherence to OAMs are outlined. In the end, the authors' recommendations include examining the influence of laws governing OAM drug pricing, OAM supply, and provider reimbursement; reducing the need for prior authorization of long-approved OAMs; identifying cost-effective ways for providers to monitor nonadherence; examining issues of provider bias in OAM prescriptions; and further elucidating in which contexts patients are likely to be able to adhere. These recommendations offer a starting point for an examination of the chain of systems influencing patient adherence and may help to finally resolve persistently high levels of OAM nonadherence.

CYP2D6 Genotype Predicts Plasma Concentrations of Tamoxifen Metabolites in Ethiopian Breast Cancer Patients

Tamoxifen displays wide inter-individual variability (IIV) in its pharmacokinetics and treatment outcome. Data on tamoxifen pharmacokinetics and pharmacogenetics from black African breast cancer patient populations is lacking. We investigated the pharmacokinetic and pharmacogenetic profile of tamoxifen and its major active metabolite, endoxifen, in Ethiopian breast cancer patients. A total of 81 female breast cancer patients on adjuvant tamoxifen therapy were enrolled. Tamoxifen (Tam) and its major metabolites, N-desmethyltamoxifen (NDM), 4-hydroxy-tamoxifen (4-HT), and (Z)-endoxifen (E) were quantified using LC-MS/MS. Genotyping for CYP2D6, CYP2C9, CYP2C19, CYP3A5, POR, and ABCB1 and UGT2B15 and copy number variation for CYP2D6 were done. The proportion of patients with low endoxifen level (<5.9 ng/mL) was 35.8% (median concentration 7.94 ng/mL). The allele frequency of CYP2D6 gene deletion (*5) and duplication (*1×N or *2×N) was 4.3% and 14.8%, respectively. Twenty-six percent of the patients carried duplicated or multiplicated CYP2D6 gene. An increase in CYP2D6 activity score was associated with increased endoxifen concentration and MR_E/NDM (p < 0.001). The IIV in endoxifen concentration and MR_E/NDM was 74.6% and 59%, respectively. CYP2D6 diplotype explained 28.2% and 44% of the variability in absolute endoxifen concentration and MR_E/NDM, respectively. The explanatory power of CYP2D6 diplotype was improved among ABCB1c.4036G carriers (43% and 65.2%, respectively for endoxifen concentration and MR_E/NDM) compared to A/A genotype. CYP2C9, CYP2C19, and CYP3A5 genotypes had no significant influence on endoxifen concentration or MR_E/NDM. In conclusion, we report a high rate of low endoxifen level as well as large IIV in tamoxifen and its metabolite concentrations. CYP2D6 is significant predictor of plasma endoxifen level in a gene-dose dependent manner.

Initiation of Adjuvant Endocrine Therapy in Black and White Women With Breast Cancer

BACKGROUND

Adjuvant endocrine therapy reduces risk of recurrence and mortality in women with hormone receptor-positive breast cancer, yet many women never initiate it. We examined the influence of race, sociocultural factors, and process-of-care factors on initiation of adjuvant endocrine therapy in a racially diverse sample.

PATIENTS AND METHODS

Eligible women were originally recruited for the Narrowing the Gaps in Adjuvant Therapy Study (2006-2011). Sociocultural and process-of-care factors were collected via telephone surveys before adjuvant therapy. Clinical factors were abstracted from charts. Penalized LASSO (least absolute shrinkage and selection operator) logistic regression model was used to identify variables associated with initiation.

RESULTS

Of the 270 women, 55.6% were black and the rest were white. Most women (74.8%) initiated therapy. A significant interaction (P = .008) was found between race and age. Black women aged ≤ 50 years had the lowest initiation (59.7%) compared to black women > 50 years (87.1%), white women ≤ 50 years (73.7%), or white women > 50 years (72.0%). Multivariate analysis found that younger black women exhibited a marginally higher risk of noninitiation compared to older black women. Additionally, ratings of financial access, presence of comorbidities, and levels of communication were all associated with endocrine therapy initiation.

CONCLUSION

Black women ≤ 50 years of age and women with financial constraints may be important subgroups for interventions. Patient-provider communication appears to be an important leverage point to foster therapy uptake.

Evaluation of the Quality of Adjuvant Endocrine Therapy Delivery for Breast Cancer Care in the United States

Importance

Randomized trials in breast cancer have demonstrated the clinical benefits of adjuvant endocrine therapy (AET) in preventing recurrence and death. The examination of concordance with AET guidelines at a national level as a measure of quality of care is important.

Objective

To investigate temporal trends and factors related to receipt of AET for breast cancer.

Design, Setting, and Participants

This retrospective cohort study included 981 729 women with breast cancer in the National Cancer Database from January 1, 2004, to December 31, 2013. Women with stages I to III breast cancer who received all or part of their treatment at the reporting institution were included in the analysis.

Main Outcomes and Measures

Temporal changes in AET receipt (estimating the annual percentage change) and AET practice patterns (using logistic regression) and the effect of AET guideline concordance on survival of women with hormone receptor-positive (HR+) breast cancer (using the multivariable Cox proportional hazards model).

Results

Of the 981 729 eligible patients (mean [SD] age, 60.8 [13.3] years), 818 435 had HR+ and 163 294 had HR-negative (HR-) cancer. Among the patients with HR+ cancer, receipt of AET increased over time, from 69.8% in 2004 to 82.4% in 2013. Among patients with HR- cancer, receipt decreased from 5.2% in 2004 to 3.4% in 2013. Hospital-level adherence (≥80% of patients with HR+ cancer received AET) increased from 40.2% in 2004 to 69.2% in 2013. Receipt of AET varied significantly by age (lower in patients ≥80 years), race (lower in African American and Hispanic participants), geographic location (lower in West South Central, Mountain, and Pacific census regions), and receptor status (lower in patients with estrogen receptor-negative and progesterone receptor-positive cancer). Surgery and radiotherapy were the factors most significantly associated with appropriate AET receipt (only 45.0% in patients who received lumpectomy without radiotherapy). Receipt of AET was associated with a 29% relative risk reduction in mortality. Based on this effectiveness estimate, if all patients with HR+ cancer received AET, approximately 14 630 lives would have been saved over 10 years.

Conclusions and Relevance

From 2004 to 2013, underuse and misuse of AET have decreased for patients with breast cancer, but optimal use has not been achieved, and significant variation in care remains. The involvement of surgery and radiotherapy were among the most significant factors associated with optimal use, which underscores the benefits of team-based care to support guideline-concordant therapy.

Impact of patient race and geographical factors on initiation and adherence to adjuvant endocrine therapy in medicare breast cancer survivors

To evaluate variations in the use of adjuvant endocrine therapy (AET) by race and geography, this research examined their influence on initiation and adherence to AET in female Medicare enrollees with breast cancer, diagnosed between 2007 and 2011.Using SEER (Surveillance, Epidemiology, and End Results Program)-Medicare data from 2007 to 2001, logistic regressions with random intercept for county of residence were used to predict AET initiation during 1st year and AET adherence assessed by the medication possession ratio (MPR) during year after initiation in a sample of fee-for-service medicare beneficiaries. Part D enrollment was required for the examination of adherence. Independent variables examined were race (black, white, or other) and geographical indicators (area deprivation, non-metropolitan status, and physician shortage).Overall, 23% of patients did not initiate AET within 1 year and 26% of the initiation sample was not adherent to AET, with average follow-up time among initiators of 141 days and an average MPR of 0.84. Significant heterogeneity (P < .01) was found between SEER sites, with initiation rates as low as 69% for Washington and as high as 81% for New Jersey; MPR adherence varied from 77% in New Jersey to 68% in Utah.Blacks had lower initiation, enrollees not in Medicaid had lower adherence, lower area deprivation counties had lower initiation, earlier SEER-Medicare years had both later initiation and nonadherence, and significant (P < .05) variations between SEER sites remained after accounting for area deprivation index, metropolitan status, and physician shortage. Subgroup analysis showed particular pockets of lower initiation for blacks with stage III tumors, on chemotherapy and lower adherence for blacks in youngest age group, with stage III tumors, tamoxifen use and blacks/others in oldest age group.Black women and women living in states with more rurality in the United States were less likely to receive guideline-recommended AET, which necessitates future efforts to alleviate these disparities to improve AET use and ultimately pursue more survival gains through optimizing adjuvant treatment use among cancer survivors.

Racial Differences in Adjuvant Endocrine Therapy Use and Discontinuation in Association with Mortality among Medicare Breast Cancer Patients by Receptor Status

Background: There are racial disparities in breast cancer mortality. Our purpose was to determine whether racial/ethnic differences in use and discontinuation of adjuvant endocrine therapy (AET) differed by hormone receptor status and whether discontinuation was associated with mortality.Methods: We conducted a retrospective cohort study with SEER/Medicare dataset of women age ≥65 years diagnosed with stage I-III breast cancer in Medicare Part-D from 2007 to 2009, stratified by hormone receptor status. We performed multivariable logistic regressions to assess racial differences for the odds of AET initiation and Cox proportional hazards models to determine the risk of discontinuation and mortality.Results: Of 14,902 women, 64.5% initiated AET <12 months of diagnosis. Among those with hormone receptor-positive cancer, 74.8% initiated AET compared with 5.6% of women with negative and 54.0% with unknown-receptor status. Blacks were less likely to initiate [OR, 0.76; 95% confidence interval (CI), 0.66-0.88] compared with whites. However, those with hormone receptor-positive disease were less likely to discontinue (HR, 0.89; 95% CI, 0.80-0.98). Women who initiated with aromatase inhibitors had increased risk of discontinuation compared with women who initiated tamoxifen (HR, 1.12; 95% CI, 1.05-1.20). Discontinuation within 12 months was associated with higher risk of all-cause (HR, 1.75; 95% CI, 1.74-2.00) and cancer-specific mortality (HR, 2.76; 95% CI, 1.74-4.38) after controlling for race/ethnicity.Conclusions: There are racial/ethnic differences in AET use and discontinuation. Discontinuing treatment was associated with higher risk of all-cause and cancer-specific mortality regardless of hormone receptor status.Impact: This study underscores the need to study factors that influence discontinuation and the survival benefits of receiving AET for hormone receptor-negative breast cancer. Cancer Epidemiol Biomarkers Prev; 26(8); 1266-75. ©2017 AACR.

Endocrine therapy initiation, discontinuation and adherence and breast imaging among 21-gene recurrence score assay-eligible women under age 65

BACKGROUND

Aside from chemotherapy utilization, limited data are available on the relationship between gene expression profiling (GEP) testing and breast cancer care. We assessed the relationship between GEP testing and additional variables and the outcomes of endocrine therapy initiation, discontinuation and adherence, and breast imaging exams in women under age 65 years.

METHODS

Data from five state cancer registries were linked with claims data and GEP results. We assessed variables associated with survivorship care outcomes in an incident cohort of 5014 commercially insured women under age 65 years, newly diagnosed with stage I or II hormone-receptor-positive, human epidermal growth factor receptor 2 (HER2) non-positive breast cancer from 2006 to 2010.

RESULTS

Among tested women, those with high Oncotype DX® Breast Recurrence Score® (RS) were significantly less likely to initiate endocrine therapy than women with low RS tumors (OR 0.40 (95% CI 0.20 to 0.81); P = 0.01). Among all test-eligible women, receipt of Oncotype DX testing was associated with a greater likelihood of endocrine therapy initiation (OR 2.48 (95% CI 2.03 to 3.04); P <0.0001). The odds of initiation were also significantly higher for tested vs. untested women among women who did not initiate chemotherapy within six months of diagnosis (OR 3.25 (95% CI 2.53 to 4.16)), with no effect in women who received chemotherapy. Discontinuation and adherence and breast imaging exams were unrelated to tested status or RS.

CONCLUSIONS

Lower endocrine therapy initiation rates among women with high RS tumors and among untested women not receiving chemotherapy are concerning, given its established efficacy. Additional research is needed to suggest mechanisms to close this gap.

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.