Oral Adjuvant Endocrine Therapy Research Articles

Adherence to adjuvant endocrine therapy for breast cancer: a qualitative exploration of attribution of symptoms among post-menopausal women.

Oral adjuvant endocrine therapy (AET) is an effective treatment for hormone receptor positive breast cancer to decrease recurrence and mortality, but adherence is poor. This study explored post-menopausal women's experiences with AET, with a particular focus on adherence to AET as well as distress and symptoms experienced prior to and during AET treatment. Participants were recruited from a hospital registry, stratified by adherence to/discontinuation of AET. Telephone interviews followed a semi-structured interview guide and were recorded and transcribed verbatim. Transcripts were systematically coded using team-based coding, with analysis of themes using a grounded theory approach. Thirty-three participants were interviewed; ages ranged from 57 to 86years. Participants included 10 discontinued patients and 23 patients who completed their AET course or were adherent to AET at the time of interviewing. Both adherent and discontinued patients reported symptoms throughout their AET treatment course, and both attributed symptoms to factors other than AET (e.g., older age and pre-existing comorbidities). However, discontinued patients were more likely to attribute symptoms to AET and to describe difficulty managing their symptoms, with some directly citing symptoms as the reason for discontinuing AET therapy. Conversely, adherent patients were more likely to describe the necessity of taking AET, despite symptoms. AET adherence was associated with beliefs about AET, symptom attribution, and symptom management. Routine symptom monitoring during AET and addressing both symptoms and patients' understanding of their symptoms may promote adherence to AET.

Identifying determinants of adherence to adjuvant endocrine therapy following breast cancer: A systematic review of reviews.

In oestrogen-receptor positive breast cancer, daily oral adjuvant endocrine therapy (ET) for at least 5 years significantly reduces risks of recurrence and breast cancer-specific mortality. However, many women are poorly adherent to ET. Development of effective adherence support requires comprehensive understanding of influences on adherence. We undertook an umbrella review to identify determinants of ET adherence. We searched PubMed, Embase, CINAHL, PsycINFO, Cochrane and PROSPERO (inception to 08/2022) to identify systematic reviews on factors influencing ET adherence. Abstracted determinants were mapped to the World Health Organization's dimensions of adherence. Reviews were quality appraised and overlap assessed. Of 5732 citations screened, 17 reviews were eligible (9 quantitative primary studies; 4 qualitative primary studies; 4 qualitative or quantitative studies) including 215 primary papers. All five WHO dimensions influenced ET non-adherence: The most consistently identified non-adherence determinants were patient-related factors (e.g. lower perceived ET necessity, more treatment concerns, perceptions of ET 'cons' vs. 'pros'). Healthcare system/healthcare professional-related factors (e.g. perceived lower quality health professional interaction/relationship) were also important and, to a somewhat lesser extent, socio-economic factors (e.g. lower levels of social/economic/material support). Evidence was more mixed for medication-related and condition-related factors, but several may be relevant (e.g. experiencing side-effects, cost). Potentially modifiable factors are more influential than non-modifiable/fixed factors (e.g. patient characteristics). The evidence-base on ET adherence determinants is extensive. Future empirical studies should focus on less well-researched areas and settings. The determinants themselves are numerous and complex in indicating that adherence support should be multifaceted, addressing multiple determinants.

Abstract PL2: Plenary Lecture 2: Premenopausal ER+ Breast Cancer: Past, Present, and Future

Abstract Adjuvant endocrine therapy for premenopausal ER+breast cancer had a relatively challenging initial pathway. The earliest trials testing adjuvant ovarian ablation in premenopausal breast cancer were hampered by the lack of ability to test for the relevant target, namely the estrogen receptor (ER). Therefore, trials testing adjuvant ovarian ablation and subsequently ovarian suppression with gonadotropin releasing hormone agonists (GnRHa) were diluted by the inclusion of women with estrogen receptor negative tumors. The subsequent demonstration of the effectiveness of adjuvant chemotherapy, initially with the CMF regimen, diverted some attention away from adjuvant endocrine therapy in premenopausal women, notwithstanding the fact that CMF, initially given for 12 months, resulted in permanent ovarian function suppression in many premenopausal women. Use of adjuvant CMF made it even more challenging to discern the added value of ovarian ablation or suppression. Oral adjuvant endocrine therapy with the selective estrogen receptor modulator tamoxifen became recommended for postmenopausal women, subsequently refined to only those with ER+ breast cancer, but the value of tamoxifen in premenopausal women was initially considered uncertain. Eventually, 5 years of adjuvant tamoxifen became a standard recommendation for premenopausal ER+ early breast cancer, although it took some time for evidence to emerge on the value of adding tamoxifen in women who received chemotherapy. The value of extending adjuvant endocrine therapy beyond 5 years was subsequently studied. More recent randomized premenopausal adjuvant endocrine therapy trials have focused of delineating the value of ovarian function suppression (OFS) added to tamoxifen or to an aromatase inhibitor. There are now a range of options for adjuvant endocrine therapy for premenopausal ER+ breast cancer, and identifying the clinical-pathologic features most appropriate for intensification of adjuvant endocrine therapy can assist with optimizing recommendations for an individual patient. Citation Format: Carlos Arteaga, Prudence Francis. Plenary Lecture 2: Premenopausal ER+ Breast Cancer: Past, Present, and Future [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PL2.

Medication delivery factors and adjuvant endocrine therapy adherence in breast cancer.

Over 50% of breast cancer patients prescribed a 5-year course of daily oral adjuvant endocrine therapy (ET) are nonadherent. We investigated the role of costs and cancer medication delivery mode and other medication delivery factors on adherence. We conducted a retrospective cohort study of commercially insured and Medicare advantage patients with newly diagnosed breast cancer in 2007-2015 who initiated ET. We examined the association between 12-month ET adherence (proportion of days covered by fills ≥ 0.80) and ET copayments, 90-day prescription refill use, mail order pharmacy use, number of pharmacies, and synchronization of medications. We used regression models to estimate nonadherence risk ratios adjusted for demographics (age, income, race, urbanicity), comorbidities, total medications, primary cancer treatments, and generic AI availability. Sensitivity analyses were conducted using alternative specifications for independent variables. Mail order users had higher adherence in both commercial and Medicare-insured cohorts. Commercially insured patients who used mail order were more likely to be adherent if they had low copayments (< $5) and 90-day prescription refills. For commercially insured patients who used local pharmacies, use of one pharmacy and better synchronized refills were also associated with adherence. Among Medicare patients who used mail order pharmacies, only low copayments were associated with adherence, while among Medicare patients using local pharmacies both low copayments and 90-day prescriptions were associated with ET adherence. Out-of-pocket costs, medication delivery mode, and other pharmacy-related medication delivery factors are associated with adherence to breast cancer ET. Future work should investigate whether interventions aimed at streamlining medication delivery could improve adherence for breast cancer patients.

Q-122 as a novel, non-hormonal, oral treatment for vasomotor symptoms in women taking tamoxifen or an aromatase inhibitor after breast cancer: a phase 2, randomised, double-blind, placebo-controlled trial

Vasomotor symptoms (hot flushes and night sweats) are experienced by more than two-thirds of women with breast cancer taking oral adjuvant endocrine therapy. Safe and effective treatments are lacking. Q-122 is a novel, non-hormonal compound that has shown promise for reducing vasomotor symptoms by modulation of oestrogen-responsive neurons in the hypothalamus. We aimed to assess the efficacy and safety of Q-122 in women with breast cancer taking oral adjuvant endocrine therapy and experiencing vasomotor symptoms. We conducted a multicentre, randomised, double-blind, placebo-controlled, proof-of-concept, phase 2 trial at 18 sites in Australia, New Zealand, and the USA. Eligible participants were women, aged 18-70 years, taking a stable dose of tamoxifen or an aromatase inhibitor following breast cancer and experiencing at least 50 self-reported moderate to severe vasomotor symptoms per week. Participants were randomly assigned (1:1) using an interactive web response system to oral Q-122 100 mg or identical placebo, twice daily for 28 days. Randomisation was stratified by BMI (≤30 kg/m2 or >30 kg/m2) and use of any of a selective serotonin reuptake inhibitor, selective norepinephrine reuptake inhibitor, gabapentin, or pregabalin. Q-122 and placebo capsules were identical in appearance and containers identically labelled. During the double-blind treatment and analysis phases, the participants, investigators, clinical research organisation staff, and sponsor were masked to treatment allocation. The primary outcome was the difference in the mean percentage change from baseline in the Vasomotor Symptom Severity Score of moderate and severe hot flushes and night sweats (msVMS-SS) between Q-122 and placebo after 28 days of treatment. Primary analysis was by modified intention-to-treat and safety was assessed in all participants receiving at least one dose of study drug. This study is registered at ClinicalTrials.gov, NCT03518138. Between Oct 24, 2018, and Sept 9, 2020, 243 patients were screened, 131 of whom were randomly assigned and received treatment (Q-122 n=65 and placebo n=66). Q-122 resulted in a significantly greater mean percentage change in msVMS-SS from baseline over 28 days of treatment compared with placebo (least squares mean: Q-122 -39% [95% CI -46 to -31] vs placebo -26% [-33 to -18]; p=0·018). Treatment-emergent adverse events were generally mild to moderate and similar between the two groups (treatment-related treatment-emergent adverse events in 11 [17%] of 65 patients in the Q-122 group vs nine [14%] of 66 in the placebo group); zero patients in the Q-122 group and two (3%) patients in the placebo group had serious adverse events. Q-122 is an effective and well tolerated non-hormonal oral treatment for vasomotor symptoms in women taking oral adjuvant endocrine therapy after breast cancer. Our results support the conduct of larger and longer studies of Q-122, with potential use extending to postmenopausal women who require an alternative to menopausal hormone therapy. QUE Oncology.

Attribution of symptoms to adjuvant endocrine therapy and association with adherence among older women with breast cancer: A qualitative study.

e24086 Background: Oral adjuvant endocrine therapy (AET) is an effective treatment for hormone receptor positive breast cancer to decrease recurrence and mortality. However, adherence to AET is poor, with 1/3 of patients not completing the recommended 5-year treatment course. Studies have shown that symptoms of the medication, such as joint pain, hot flashes, and fatigue, are associated with AET discontinuation. While previous studies have focused on symptoms post-AET initiation, preliminary evidence suggests that pre-AET symptoms may be an important predictor of early AET discontinuation. We used qualitative interviews to explore adherence to AET and patients’ attribution of symptoms to AET to provide context for a larger quantitative study on the role of patient-reported distress pre-AET as a predictor of AET discontinuation. Methods: Participants were recruited from the Froedtert/MCW Cancer Center registry, stratified by high (≥4) and low pre-AET Distress Thermometer scores and adherence to/discontinuation of AET. Semi-structured phone interviews followed an interview guide focused on constructs previously identified in the literature as having strong associations with AET adherence. Interviews were recorded and transcribed. A multidisciplinary team developed a codebook based on the conceptual framework describing AET discontinuation by AlOmeir et al. as well as other themes that emerged from the data. Results: Interviews were conducted with 31 participants; ages ranged from 57-86 years. Participants were diverse with respect to race/ethnicity (55% white, 26% Black, 13% Latina, and 6% other racial/ethnic groups). Participants who reported symptoms described hot flashes, joint pain, low appetite, memory loss, depression, and fatigue. We saw support for previous findings by AlOmeir et al in which ability to deal with symptoms affected the decision to continue AET. We uncovered additional nuance related to attribution of symptoms, in that some participants attributed their symptoms to a side effect of AET, while others attributed symptoms to other factors including older age, recent completion of other cancer treatments, and psychological burden associated with a cancer diagnosis and treatment. Those who did not attribute symptoms to AET focused on AET as necessary treatment to increase survival, while those who attributed symptoms to AET reported a more negative AET experience in general, with AET described as an additional burden after cancer. Conclusions: Symptom attribution rather than experience of specific symptoms may be a key factor leading to discontinuation of AET. Patient-reported symptoms and associated distress pre-AET may be a viable way to identify patients at high-risk for AET nonadherence, allowing for timely intervention. This will be quantitatively tested in a large sample.

Abstract A076: Adherence to adjuvant endocrine therapy: Do racial disparities persist among the insured?

Abstract Purpose: Adjuvant endocrine therapy (AET) improves survival in women with hormone receptor-positive (HR+) breast cancer (BC). Yet medication adherence is suboptimal. The aim of this study was to assess adherence to AET among insured women using innovative statistical approaches. Methods: Black and White women diagnosed with HR+ BC were identified from two health maintenance organizations. Automated pharmacy records captured oral AET prescriptions and refill dates. Logistic regression identified predictors of adherence defined in terms of proportion of days covered (PDC) (&amp;gt;=80%) and medication gap of ≤10 days. A zero-inflated negative binominal (ZINB) regression model identified variables associated with the total number of days of medication gaps. Results: A total of 1,925 women met inclusion criteria. Eighty percent of women were adherent per the PDC measure; 44% had a medication gap of ≤10 days; and 24% of women had zero days without any medication gaps. Race and age were significant predictors of adherence in all multivariable models. Black women were less likely to have PDC &amp;gt;=80% than Whites (OR=0.72; 95%CI: 0.57-0.90; p&amp;lt;0.01), and they were less likely to have a medication gap of ≤10 days (OR=0.65; 95%CI: 0.54-0.79; p&amp;lt;0.001). Women 25-49 years old were less likely to have PDC &amp;gt;=80% than women 65-93 years old (OR=0.65; 95%CI: 0.48-0.87; p&amp;lt;0.001), and they also were less likely to have a medication gap of ≤10 days (OR=0.73; 95%CI: 0.57-0.93; p&amp;lt;0.01). In the zero-inflated negative binominal model, Black women were less likely to having no medication gaps compared to Whites (OR=0.46; 95%CI: 0.54-0.79; p&amp;lt;0.001), and women 25-49 years old were less likely to have no medication gaps compared to women 65-93 years old (OR=0.61; 95%CI: 0.42-0.88; p&amp;lt;0.01). Conclusions: Disparities in adherence to AET persist among insured women, particularly in Black and young women, highlighting a need for interventions among this population. Novel statistical approaches to study adherence, such as the ZINB approach, appear to constitute a useful alternative to the dichotomous PDC variable to tailor analysis to adherence patterns. Citation Format: Dennis Tolsma, Mahlet G. Tadesse, Arnethea Sutton, Lee Cromwell, Georges Adunlin, Teresa M. Salgado, Jun He, Martha Trout, Brandi E. Robinson, Megan C. Edmonds, Hayden B. Bosworth, Vanessa B. Sheppard. Adherence to adjuvant endocrine therapy: Do racial disparities persist among the insured? [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr A076.

Patient-reported Adherence to Adjuvant Aromatase Inhibitor Therapy Using the Morisky Medication Adherence Scale: An Evaluation of Predictors.

Endocrine therapy is part of standard adjuvant therapy for patients with hormone receptor-positive breast cancer and has been shown to improve recurrence-free and overall survival. However, adherence to endocrine therapy is suboptimal and is difficult to measure. In this study we evaluate the feasibility of using the Morisky Medication Adherence Scale (MMAS) to assess patient adherence to aromatase inhibitor (AI) therapy. Patients with stage 1 to 3, hormone receptor-positive breast cancer receiving adjuvant AI therapy were prospectively enrolled on an Institutional Review Board approved protocol. The MMAS questionnaire was administered to each patient and adherence was measured. Information on duration of AI therapy, patient and tumor characteristics, and treatment was collected. A multivariable logit model approach was utilized to evaluate potential barriers to adherence. Between 2011 and 2014, 100 patients were enrolled. The distribution of adherence levels was 13% low, 37% medium, and 50% high. High adherence was reported more frequently in white women (58%), patients with stage 2 and 3 disease (54%), and patients who did not receive chemotherapy (62%). Multivariable analysis demonstrated that higher adherence was more likely in white women compared with African American women (estimated odds ratio=2.8). Using the MMAS, only 50% of women with stage 1 to 3 breast cancer reported high adherence to AI therapy, consistent with other reports showing suboptimal adherence to adjuvant endocrine therapy. The MMAS allows for the rapid assessment of adherence to oral adjuvant endocrine therapy and is valuable in a busy clinical setting.

Prevalence and determinants of adherence to oral adjuvant endocrine therapy among breast cancer patients in Singapore

Objective:The success of oral adjuvant endocrine therapy (OAET) is greatly influenced by patients’ level of adherence to treatment. The objective of this study is to measure the prevalence and determinants of adherence to OAET among breast cancer patients in Singapore.Methods:A cross-sectional survey of patients supplemented by analysis of their prescription records was used to collect data. Adherence to OAET was assessed using the Morisky Medication Adherence Scale-4 items and evaluation of refill gaps. Univariate and multivariate analyses were done to evaluate the association between patients’ characteristics and adherence to OAET.Results:A total of 157 women who have started OAET at least 6 months before the time of interview participated in the study, of which less than half (64 patients, 40.8%) of the patients had high adherence. Univariate analysis identified patients who were 57 years or older (P = 0.027), unemployed (P = 0.027), on aromatase inhibitors (P = 0.023), on three or more concurrent medications (P = 0.001), and had one or more comorbidities (P = 0.000) to be significantly more adherent. However, only the number of comorbidities was found to be an independent predictor of adherence in a multiple logistic regression analysis (adjusted odds ratio = 2.60; 95% confidence interval = 1.208–5.593; P = 0.015). Forgetfulness was the main reason for nonadherence mentioned by 63 (67.7%) of the 93 nonadherent patients.Conclusions:Low level of OAET adherence was found in this study, and forgetfulness was cited as the main reason for nonadherence. Patients were generally receptive to the implementation of various strategies to assist them with their medication-taking behavior

The adherence and tolerance of adjuvant endocrine therapy in geriatric breast cancer patients

BackgroundAdherence to and tolerance of oral adjuvant endocrine therapy (ET) are important to improve survival for hormone receptor (HR)-positive breast cancer patients. To date, there has been limited literature discussing this issue in elderly patients. Herein we have presented a retrospective study to analyze the tolerance to and completion rate of ET in a single medical center in Taiwan. Patients and methodsFrom 1996 to 2009, a total of 269 female patients over 70 years of age with primary HR-positive operable breast cancer were registered and analyzed for this study. ResultsIn our study, the completion rate was 49.4% for all 269 patients and was 56.7% for those willing to initiate ET. Of the 72 patients that discontinued ET early but not due to recurrence, 9.7% had well-documented ET-related adverse events, 33.3% refused to undergo ET but remained in follow-up, 44.4% did not undergo ET because of loss of follow-up before a complete ET period, and 12.5% of the patients discontinued ET arising from other medical conditions. The switch therapy, tamoxifen followed by aromatase inhibitor, showed a greater completion rate, compared with upfront tamoxifen or aromatase inhibitor. ConclusionsThe completion rate for patients who underwent oral ET in our study was similar to previous studies. The switch method of adjuvant oral endocrine therapy demonstrated a better tolerance and adherence in elderly breast cancer patients, compared with tamoxifen or aromatase inhibitor alone.

Menopausal symptoms in breast cancer survivors nearly 6 years after diagnosis

We investigated the prevalence and severity of menopausal symptoms, nearly 6 years from diagnosis, in women who had not experienced recurrent breast cancer or a new primary breast cancer (active disease) and were no longer taking oral adjuvant endocrine therapy (OAET). A total of 1,683 women recruited within 12 months of diagnosis with invasive breast cancer completed an enrollment questionnaire and five annual follow-up questionnaires. Only women who had never reported active disease and were not taking OAET at their fifth follow-up were included in the analysis. Women previously recruited to a study of sex steroid levels provided community control data. Menopausal symptoms were assessed with the Menopause-Specific Quality of Life Questionnaire (MenQOL). Eight hundred forty-three women without active disease and not taking OAET completed the fifth follow-up questionnaire, on average, 5.8 years after diagnosis. Most had stage I (59.5%) and hormone receptor-positive disease (77.9%) at diagnosis and were postmenopausal (92.8%). Those aged 50 to 59 years were more likely to report any symptoms (P = 0.01) and more severe symptoms (P < 0.001) than older and younger women. There was no independent impact of chemotherapy on MenQOL vasomotor and sexual domain scores. Women with breast cancer had significantly higher vasomotor domain (P ≤ 0.002) and sexual domain (P ≤ 0.004) scores than community controls. Vasomotor and sexual symptoms are highly prevalent in breast cancer survivors and are not simply a function of OAET or chemotherapy. Given the adverse impact of these symptoms, effective interventions are needed to alleviate them in women who have completed their breast cancer treatment.

Obesity is associated with a poorer prognosis in women with hormone receptor positive breast cancer

ObjectiveWhether moderate to severe obesity (body mass index (BMI)≥30 to <40kg/m2) contributes to breast cancer recurrence and mortality remains uncertain. Subjects and methods1199 women, recruited within 12 months of their diagnosis of hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2−) invasive breast cancer completed an enrolment questionnaire and an annual follow-up questionnaire every 12 months for another 5 years. The impact of obesity on time to either local or distant recurrence or new breast cancer, or death due to breast cancer was determined by Cox regression. Women in the most extreme categories of BMI (<18.5 and ≥40) were excluded from the analysis. ResultsOf the 1155 included women, mean age, 58.4±11.6 years, 53.8% had Stage 1 disease and 88.9% received oral adjuvant endocrine therapy (OAET) within 2 years of diagnosis. The likelihood of an event was significantly associated with moderate to severe obesity (HR=1.71, 95%CI, 1.12–2.62, p=0.014), disease beyond Stage 1 (HR=2.87, 95% CI 1.73–4.75, p<0.001), OAET (HR=0.26, 95%CI 0.14–0.46, p<0.001), mastectomy (HR=3.28, 95%CI 1.98–5.44, p<0.001) and radiotherapy (HR=2.12, 95%CI 1.24–3.63, p=0.006). For Stage 1 disease, only moderate to severe obesity (HR 3.23, 95%CI 1.48–7.03, p=0.003) and OAET use (HR 0.41, 95%CI 0.17–0.98, p=0.046) were significantly associated with an event. ConclusionModerate to severe obesity is associated with a poorer invasive breast cancer prognosis; this is also true for women with Stage 1 disease, and is independent of age and treatment.

A comparison of the characteristics, treatment and outcome after 5years, of Australian women aged 70+with those aged&lt;70years at the time of diagnosis of breast cancer

Management of older women with breast cancer (BC) is challenging, as age-related comorbidities may limit treatment. We present 5-year follow-up data from women aged 70 years or older (70+), at the time of diagnosis of their BC, compared with younger women (<70 years). Data is from an Australian cohort study of women with their first episode of invasive BC (Bupa study). Participants completed an enrollment questionnaire (EQ) within 12 months of diagnosis and annual follow-up questionnaires (FQ) for 5 years (FQ1-5). Data collected included details of the BC and its treatment. Psychological wellbeing was measured by the Psychological General Wellbeing Index (PGWB). At diagnosis, 274 (16%) women were aged 70+ and of them, 90% were aged 70-79 years. Compared with women aged <70 years, the women aged 70+ were less likely to have positive nodes, they were less likely to receive radiotherapy and chemotherapy and were more likely to have pre-existing cardiovascular morbidities. By FQ5 women aged 70+ were less likely to be taking oral adjuvant endocrine therapy (OAET) and were more likely to have died from causes other than BC. At FQ5, women 70+ reported less anxiety and better self-control. Women aged 70+, compared to <70 years, had less advanced disease, received radiation and chemotherapy less often, were more likely to have cardiovascular disease at the time of diagnosis, were less likely to be taking OAET at the 5-year assessment, and were more likely to die of causes other than breast cancer.

Patterns of use of oral adjuvant endocrine therapy in Australian breast cancer survivors 5 years from diagnosis

Oral adjuvant endocrine therapy (OAET) substantially improves the survival of women with hormone receptor-positive (HR) breast cancer. However, we reported previously that at 3 to 4 years after diagnosis, 18% of affected women are not using OAET primarily because of estrogen deficiency symptoms. The aim of this study was to determine the use of OAET in women with HR breast cancer 5 to 6 years from diagnosis.Analysis was carried out using data from the Bupa Health Foundation's Health and Wellbeing After Breast Cancer Study, a cohort study of 1,683 women with breast cancer who were recruited in Victoria, Australia between 2004 and 2006. All women completed an enrollment questionnaire within 12 months of diagnosis and an annual follow-up questionnaire (FQ) for 5 years. The fifth FQ was completed 5.7 years from the time of diagnosis. Use of OAET was self-reported in response to a series of questions.A minimal exposure to OAET of at least 5 years (OAET in all six FQs) was reported by 19.7% of the women (n = 212), and another 46.7% (n = 503) received a minimal exposure of at least 4 years (OAET in five questionnaires). In total, 82.1% (n = 883) of the women would have received at least 3 years of treatment (OAET in at least four questionnaires). Only 7.8% (n = 84) reported never using OAET.Most women with HR breast cancer who survive at least 5 years have persisted with OAET despite the adverse effects of estrogen depletion.

Understanding discontinuation of oral adjuvant endocrine therapy by women with hormone receptor–positive invasive breast cancer nearly 4 years from diagnosis

The aim of this study was to investigate the extent of discontinuation of oral adjuvant endocrine therapy (OAET) in women nearly 4 years from the diagnosis of their first episode of invasive breast cancer and the reasons for such discontinuation. We used a large, prospective cohort study of women who had been diagnosed with their first episode of invasive breast cancer between 2004 and 2006, recruited through a state-based cancer registry. All participants completed an enrollment questionnaire (EQ) within 12 months of diagnosis and annual follow-up questionnaires (FQs) thereafter. The data in this report were obtained from the EQ and the first three FQs. A total of 1,370 women with hormone receptor-positive disease completed the EQ. At the completion of the third FQ nearly 4 years from diagnosis, 1,193 women remained in the study. Use of OAET peaked by 2 years postdiagnosis. At nearly 4 years from diagnosis, 18% of the 1,193 women remaining in the study were not taking OAET. Of these women, just more than half had ceased therapy mainly owing to a range of adverse effects, predominantly estrogen deficiency symptoms, but the remainder (8% of women remaining in the study) had never used OAET. Our study confirms that early discontinuation of OAET due to estrogen deficiency symptoms remains an important issue despite calls for strategies to address this problem. The number of women potentially suitable for OAET but not receiving it was almost as great as the number of those who have discontinued therapy.