Letrozole in the extended adjuvant setting: MA.17

Treatment utilization and non-drug interventions for vasomotor symptoms in breast cancer survivors taking endocrine therapy: Real-world findings from the United States and Europe

OBJECTIVES

Vasomotor symptoms induced by endocrine therapy are common in breast cancer survivors and a risk factor for therapy discontinuation and lower quality of life. The REALISE study evaluated the real-world treatment landscape in breast cancer survivors with vasomotor symptoms taking endocrine therapy, including pharmaceuticals, lifestyle changes, and over-the-counter products.

STUDY DESIGN

Secondary analysis of the Adelphi Vasomotor Disease Specific Programme™, a large cross-sectional point-in-time survey and chart review conducted in the US and five European countries (February-October 2020). Oncologists provided demographic, clinical, and treatment data for adult breast cancer survivors with induced vasomotor symptoms taking endocrine therapy (tamoxifen or aromatase inhibitors); patients voluntarily completed self-report surveys on their symptom severity, concomitant sleep and/or mood symptoms, lifestyle changes, and use of over-the-counter products.

MAIN OUTCOME MEASURES

Patient characteristics; vasomotor symptom severity; use of pharmaceuticals, lifestyle changes, and over-the-counter products (from pre-defined lists); lines of treatment.

RESULTS

Overall, 77 oncologists reported data for 618 breast cancer survivors, of whom 183 (29.6 %) completed self-report forms. Physicians classified 420 (68.0 %) women as experiencing moderate-severe vasomotor symptoms, of whom 66.9 % were receiving treatment. In total, 15.2 % of all breast cancer survivors were prescribed systemic hormone therapy. Venlafaxine (24.7 %), citalopram (16.5 %), and paroxetine (13.6 %) were the most commonly prescribed nonhormonal medications. Lifestyle changes (77.8 %) and over-the-counter products (61.6 %) were common, especially in patients with concomitant sleep and/or mood symptoms.

CONCLUSIONS

Despite contraindications, a relatively large proportion of treatment-seeking breast cancer survivors with vasomotor symptoms were prescribed systemic hormone therapy. This, combined with high patient-reported use of lifestyle changes and over-the-counter products, suggests a need for symptomatic relief and demand for new nonhormonal alternatives with established safety profiles in this population.

Tata Memorial Centre Evidence Based Management of Breast cancer

ABSTRACT

The incidence of breast cancer is increasing rapidly in urban India due to the changing lifestyle and exposure to risk factors. Diagnosis at an advanced stage and in younger women are the most concerning issues of breast cancer in India. Lack of awareness and social taboos related to cancer diagnosis make women feel hesitant to seek timely medical advice. As almost half of women develop breast cancer at an age younger than 50 years, breast cancer diagnosis poses a huge financial burden on the household and impacts the entire family. Moreover, inaccessibility, unaffordability, and high out-of-pocket expenditure make this situation grimmer. Women find it difficult to get quality cancer care closer to their homes and end up traveling long distances for seeking treatment. Significant differences in the cancer epidemiology compared to the west make the adoption of western breast cancer management guidelines challenging for Indian women. In this article, we intend to provide a comprehensive review of the management of breast cancer from diagnosis to treatment for both early and advanced stages from the perspective of low-middle-income countries. Starting with a brief introduction to epidemiology and guidelines for diagnostic modalities (imaging and pathology), treatment has been discussed for early breast cancer (EBC), locally advanced, and MBC. In-depth information on loco-regional and systemic therapy has been provided focusing on standard treatment protocols as well as scenarios where treatment can be de-escalated or escalated.

Targeting the formation of estrogens for treatment of hormone dependent diseases-current status

Local formation and action of estrogens have crucial roles in hormone dependent cancers and benign diseases like endometriosis. Drugs that are currently used for the treatment of these diseases act at the receptor and at the pre-receptor levels, targeting the local formation of estrogens. Since 1980s the local formation of estrogens has been targeted by inhibitors of aromatase that catalyses their formation from androgens. Steroidal and non-steroidal inhibitors have successfully been used to treat postmenopausal breast cancer and have also been evaluated in clinical studies in patients with endometrial, ovarian cancers and endometriosis. Over the past decade also inhibitors of sulfatase that catalyses the hydrolysis of inactive estrogen-sulfates entered clinical trials for treatment of breast, endometrial cancers and endometriosis, with clinical effects observed primarily in breast cancer. More recently, inhibitors of 17beta-hydroxysteroid dehydrogenase 1, an enzyme responsible for formation of the most potent estrogen, estradiol, have shown promising results in preclinical studies and have already entered clinical evaluation for endometriosis. This review aims to provide an overview of the current status of the use of hormonal drugs for the major hormone-dependent diseases. Further, it aims to explain the mechanisms behind the -sometimes- observed weak effects and low therapeutic efficacy of these drugs and the possibilities and the advantages of combined treatments targeting several enzymes in the local estrogen formation, or drugs acting with different therapeutic mechanisms.

Predictors of adherence and the role of primary non-adherence in antihormonal treatment of breast cancer

BACKGROUND

Antihormonal treatment for hormone receptor (HR) positive breast cancer has highly beneficial effects on both recurrence rates and survival. We investigate adherence and persistence in this group of patients.

METHODS

The study population comprised 1192 patients with HR-positive breast cancer who were prescribed adjuvant antihormonal treatment from 2004 to 2013. Adherence was defined as a medical possession ratio (MPR) of ≥80.

RESULTS

Of the 1192 included patients, 903 (75.8%) were adherent and 289 (24.2%) were non-adherent. Primary non-adherence was seen in 101 (8.5%) patients. The extremes of age (< 40 and ≥ 80 years) were associated with poor adherence. Patients with metastasis to axillary lymph nodes and those who received radiotherapy and/or chemotherapy were more likely to be adherent. Better adherence was also shown for those who switched medication at 2 years after diagnosis. Primary non-adherence seems to be associated with cancers with a good prognosis.

CONCLUSION

Adherence to antihormonal therapy for breast cancer is suboptimal. Primary non-adherence occurs among patients with a relatively good prognosis. Non-adherent patients tend to terminate their antihormonal therapy in the initial part of the treatment period. Targeted interventions to improve adherence should be focused on the first part of the treatment period.

Extended adjuvant endocrine treatment for premenopausal women: A Delphi approach to guide clinical practice

The use of an aromatase inhibitor (AI) in combination with ovarian function suppression (OFS) has become the mainstay of adjuvant endocrine therapy in high-risk premenopausal patients with hormone receptor-positive breast cancer. Although five years of such therapy effectively reduces recurrence rates, a substantial risk of late recurrence remains in this setting. Multiple trials have shown that extending AI treatment beyond five years could offer further protection. However, as these studies comprised only postmenopausal patients, no direct evidence currently exists to inform about the potential benefits and/or side effects of extended AI + OFS therapies in premenopausal women. Given these grey areas, we conducted a Delphi survey to report on the opinion of experts in breast cancer treatment and summarize a consensus on the discussed topics. A total of 44 items were identified, all centred around two main themes: 1) defining reliable prognostic factors to pinpoint premenopausal patients eligible for endocrine therapy extension; 2) designing how such therapy should optimally be administered in terms of treatment combinations and duration based on patients' menopausal status. Each item was separately discussed and anonymously voted by 12 experts representing oncological institutes spread across Italy. The consensus threshold was reached in 36 out of 44 items (82%). Herein, we discuss the levels of agreement/disagreement achieved by each item in relation to the current body of literature. In the absence of randomized trials to guide the tailoring of extended AI treatment in premenopausal women, conclusions from our study provide a framework to assist routine clinical practice.

Using machine learning to predict individual patient toxicities from cancer treatments

PURPOSE

Machine learning (ML) is a powerful tool for interrogating datasets and learning relationships between multiple variables. We utilized a ML model to identify those early breast cancer (EBC) patients at highest risk of developing severe vasomotor symptoms (VMS).

METHODS

A gradient boosted decision model utilizing cross-sectional survey data from 360 EBC patients was created. Seventeen patient- and treatment-specific variables were considered in the model. The outcome variable was based on the Hot Flush Night Sweats (HFNS) Problem Rating Score, and individual scores were dichotomized around the median to indicate individuals with high and low problem scores. Model accuracy was assessed using the area under the receiver operating curve, and conditional partial dependence plots were constructed to illustrate relationships between variables and the outcome of interest.

RESULTS

The model area under the ROC curve was 0.731 (SD 0.074). The most important variables in the model were as follows: the number of hot flashes per week, age, the prescription, or use of drug interventions to manage VMS, whether patients were asked about VMS in routine follow-up visits, and the presence or absence of changes to breast cancer treatments due to VMS. A threshold of 17 hot flashes per week was identified as being more predictive of severe VMS. Patients between the ages of 49 and 63 were more likely to report severe symptoms.

CONCLUSION

Machine learning is a unique tool for predicting severe VMS. The use of ML to assess other treatment-related toxicities and their management requires further study.

Tailoring neoadjuvant treatment of HR-positive/HER2-negative breast cancers: Which role for gene expression assays?

Neoadjuvant chemotherapy (NACT) for breast cancer (BC) increases surgical and conservative surgery chances. However, a significant proportion of patients will not be eligible for conservative surgery following NACT because of large tumor size and/or low chemosensitivity, especially for hormone receptor (HR)-positive/ human epidermal growth factor receptor 2 (HER2)-negative tumors, for which pathological complete response rates are lower than for other BC subtypes. On the other hand, for luminal BC neoadjuvant endocrine therapy could represent a valid alternative. Several gene expression assays have been introduced into clinical practice in last decades, in order to define prognosis more accurately than clinico-pathological features alone and to predict the benefit of adjuvant treatments. A series of studies have demonstrated the feasibility of using core needle biopsy for gene expression risk testing, finding a high concordance rate in the risk result between biopsy sample and surgical samples. Based on these premises, recent efforts have focused on the utility of gene expression signatures to guide therapeutic decisions even in the neoadjuvant setting. Several prospective and retrospective studies have investigated the correlation between gene expression risk score from core needle biopsy before neoadjuvant therapy and the likelihood of 1) clinical and pathological response to neoadjuvant chemotherapy and endocrine therapy, 2) conservative surgery after neoadjuvant chemotherapy and endocrine therapy, and 3) survival following neoadjuvant chemotherapy and endocrine therapy. The purpose of this review is to provide an overview of the potential clinical utility of the main commercially available gene expression panels (Oncotype DX, MammaPrint, EndoPredict, Prosigna/PAM50 and Breast Cancer Index) in the neoadjuvant setting, in order to better inform decision making for luminal BC beyond the exclusive contribution of clinico-pathological features.

Tailoring adjuvant endocrine therapy in early breast cancer: When, how, and how long?

Endocrine therapy represents the gold standard for the adjuvant treatment of luminal-like early breast cancer, but its personalization is still a major point of debate. To define the most appropriate therapeutic strategy, both the patient's menopausal status at the moment of diagnosis and the individual risk of disease recurrence should be taken into account. Five years of therapy with tamoxifen represent the standard of care for low-risk pre/perimenopausal patients, whilst the combination of ovarian suppression with tamoxifen or an aromatase inhibitor should be considered for high-risk patients. Also, to high-risk patients, an extended strategy can be proposed. Postmenopausal patients, instead, should receive an upfront aromatase inhibitor and an extended strategy can be considered for a high risk of disease recurrence. Aim of this review is to set a focus on the major studies investigating the optimal type and duration of adjuvant endocrine therapy and evaluate emerging options.

Network Modeling of Complex Time-Dependent Changes in Patient Adherence to Adjuvant Endocrine Treatment in ER+ Breast Cancer

Early patient discontinuation from adjuvant endocrine treatment (ET) is multifactorial and complex: Patients must adapt to various challenges and make the best decisions they can within changing contexts over time. Predictive models are needed that can account for the changing influence of multiple factors over time as well as decisional uncertainty due to incomplete data. AtlasTi8 analyses of longitudinal interview data from 82 estrogen receptor-positive (ER+) breast cancer patients generated a model conceptualizing patient-, patient-provider relationship, and treatment-related influences on early discontinuation. Prospective self-report data from validated psychometric measures were discretized and constrained into a decisional logic network to refine and validate the conceptual model. Minimal intervention set (MIS) optimization identified parsimonious intervention strategies that reversed discontinuation paths back to adherence. Logic network simulation produced 96 candidate decisional models which accounted for 75% of the coordinated changes in the 16 network nodes over time. Collectively the models supported 15 persistent end-states, all discontinued. The 15 end-states were characterized by median levels of general anxiety and low levels of perceived recurrence risk, quality of life (QoL) and ET side effects. MIS optimization identified 3 effective interventions: reducing general anxiety, reinforcing pill-taking routines, and increasing trust in healthcare providers. Increasing health literacy also improved adherence for patients without a college degree. Given complex regulatory networks’ intractability to end-state identification, the predictive models performed reasonably well in identifying specific discontinuation profiles and potentially effective interventions.

Vasomotor symptoms in early breast cancer-a "real world" exploration of the patient experience

BACKGROUND

Despite the frequency of vasomotor symptoms (VMS) in patients with early breast cancer (EBC), their optimal management remains unknown. A patient survey was performed to determine perspectives on this important clinical challenge.

METHODS

Patients with EBC experiencing VMS participated in an anonymous survey. Patients reported on the frequency and severity of VMS using the validated Hot Flush Rating Scale (HFRS) and ranked their most bothersome symptoms. Respondents were also asked to determine endpoints that defined effective treatment of VMS and report on the effectiveness of previously tried interventions.

RESULTS

Responses were received from 373 patients, median age 56 years (range 23-83), who experienced an average of 5.0 hot flashes per day (SD 6.57). Patients reported the most bothersome symptoms to be feeling hot/sweating (155/316, 49%) and sleeping difficulties (86/316, 27%). Fifty-five percent (201/365) of patients would consider a treatment to be effective if it reduced night-time awakenings. While 68% of respondents were interested in trying interventions from their healthcare team to manage VMS, only 18% actually did so. Of the 137 patients who had tried an intervention for VMS, pharmacological treatments, exercise, and relaxation strategies were more likely to be effective, while therapies such as melatonin and black cohosh were deemed less effective.

CONCLUSION

VMS are a common and bothersome problem for EBC patients, with a minority receiving interventions to manage these symptoms. Further research is needed to identify patient-centered strategies for managing these distressing symptoms.

Assessment of compliance with hormonal therapy in early breast cancer patients with positive hormone receptor phenotype: A single institution study

Background

Adherence to long-term adjuvant hormonal therapy in hormonal receptors (HR)-positive breast cancer is really challenging and can affect the survival outcome. The present study aims to assess rate of compliance with hormonal therapy and possible predictive factors in a single institute in Saudi Arabia.

Patients &methods

We recruited patients with HR-positive breast cancer who presented to oncology outpatient clinics. Patients were assessed for compliance using a study questionnaire. Compliance was defined as taking ≥80% of prescribed doses of oral hormonal therapy. Different epidemiological, clinical, pathological and treatment data were checked in patients’ medical records and correlated with compliance/interruption of hormonal therapy.

Results

Among the 203 recruited patients, 95.1% were compliant with hormonal therapy, while it was interrupted in 16.7% of patients, and 58.1% reported missing intake of hormonal pills. Age >50 years, having permanent job and higher education level were significantly associated with non-compliance in univariate analysis. On multivariate analysis, job status was the only independent predictor of non-compliance. The following parameters were significantly related to hormonal therapy interruption: marital status (single: 28.8% vs married patients: 12.6%, p = 0.01) and residence location (Makkah: 11.7% vs. outside Makkah: 25.3%, p = 0.019), lymphovascular invasion (LVI) (No: 20.9%, Yes: 7.8%, p = 0.025) and N0 tumours (compared to node-positive patients, p = 0.008). On multivariate analysis, marital status, residence location and N-stage, maintained significance relation with hormonal therapy interruption.

Conclusion

Compliance with hormonal therapy was high in the study cohort. Marital status, residence location, job status and N-stage may be related to interruption/compliance with hormonal therapy.

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Compliance rate to adjuvant hormonal therapy was high in Saudi patients.

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Job status was significantly associated to hormonal therapy compliance.

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Marital status, residence location and N0-stage were linked with hormonal therapy interruption.

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Side effects were related to hormonal therapy interruption in a minority of patients.

Monitoring serum estradiol levels in breast cancer patients during extended adjuvant letrozole treatment after five years of tamoxifen: a prospective trial

PURPOSE

To analyze whether monitoring serum estradiol (E2) levels using a highly sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) method may identify patients with AI failure with E2 levels below the lower limit of quantification (LLOQ) after schwitching from tamoxifen to letrozole.

METHODS

In a prospective study of breast cancer patients switching to letrozole treatment after previous tamoxifen, plasma estrogen levels were measured at baseline and after 3- and 12-months using LC-MS/MS.

RESULTS

Forty-six patients were classified postmenopausal and entered into the final analysis. Thirty-nine (85%) patients had three- and 12-month E2 concentrations below the LLOQ (5 pmol/L). In the seven patients classified as AI-failures during letrozole treatment, serum E2-MS level rose above 5 pmol/L at 3 months with a mean E2-MS 77.5 pmol/L or 12 months with a mean E2-MS 21 pmol/L. None of the baseline variables i.e., age at diagnosis, age at study entry, age at menarche, BMI, endometrial thickness, total ovarian volume, baseline FSH, E2-IA, or E2-MS were significantly associated with the risk of AI failure in logistic regression. E2 levels at baseline measured by E2-IA did not significantly correlate to the levels measured by E2-MS.

CONCLUSIONS

There is a relatively high risk of inadequate estrogen suppression in patients who switch from tamoxifen treatment to AIs. The use of sensitive and specific assays, such as LC-MS/MS methods, to monitor estrogen levels during AI treatment is essential to minimize the risk of a proceeding inefficient endocrine therapy.

From Theory to Practice: Bone Health in Women with Early Breast Cancer Treated with Aromatase Inhibitors

Aromatase inhibitors (AI) are extensively used as adjuvant endocrine therapy in post-menopausal women with hormone receptor-positive early breast cancer (HR+ EBC), but their impact on bone health is not negligible. This work aimed to assess bone loss, fracture incidence, and risk factors associated with these events, as well as the prognostic influence of fractures. We have conducted a retrospective cohort study of women with HR+ EBC under adjuvant therapy with AI, during a 3-year period. Four-hundred-and-fifty-one eligible women were reviewed (median age 68 years). Median time under AI was 40 months. A fracture event occurred in 8.4%, mostly in the radium and femoral neck and in older women (mean 74 vs. 68 years, p = 0.006). Age (OR 1.01, 95% CI 1.01-1.07, p = 0.024) and time under AI (OR 1.02, 95% CI 1.00-1.04, p = 0.037) were independent predictors of fracture, with a fair discrimination (AUC 0.71). Analysis of disease-free survival according to fracture event varied between groups, disfavoring the fracture cohort (at 73 months, survival 78.6%, 95% CI, 47.6-92.4 vs. 95.6%, 95% CI, 91.2-97.8, p = 0.027). The multivariate model confirmed the prognostic impact of fracture occurrence (adjusted HR of 3.17, 95% CI 1.10-9.11; p = 0.032). Bone health is often forgotten, despite its great impact in survivorship. Our results validate the pathophysiologic link between EBC and bone metabolism, which translates into EBC recurrence. Further research in this area may help refine these findings. Moreover, early identification of women at higher risk for fractures is warranted.

Simulating Time-Dependent Patterns of Nonadherence by Patients With Breast Cancer to Adjuvant Oral Endocrine Therapy

PURPOSE

Nearly 40% of patients with breast cancer discontinue their adjuvant oral endocrine treatment (ET). We measured discontinuation rates of ET at a comprehensive cancer center. We then used an iterative approach to model patterns of determinants associated with discontinuation of ET.

METHODS

Patients with nonmetastatic breast cancer receiving active adjuvant ET were approached by nurse practitioners to complete an anonymous survey at one time point. We simulated a prospective model by iteratively regressing adverse effects onto adherence status across windowed time periods of 2 to 3 consecutive years, bootstrapping the smaller group of nonadherent patients and subsampling the larger adherent group.

RESULTS

From February to April 2013, 216 participants were enrolled in the study. Forty patients (18.5%) reported that they had discontinued ET during the first 5 years of ET, and an additional four patients (1.9%) missed > 20% of their doses. Using two-sided significance tests, simulations showed that all 13 ET adverse effects and reasons for discontinuation were significantly related to discontinuation at some time point during ET. Worry about ET cost (odds ratio [OR], 1.79), emotional distress (OR, 1.72), and bone and joint pain (OR, 1.69) were the three most impactful reasons for discontinuation, with varying patterns of influence over time.

CONCLUSION

These analyses provide preliminary evidence that there are varying patterns of discontinuation of ET. Although some reasons for discontinuation exerted a steady influence over the 6-year ET trajectory (ie, bone and joint pain), other reasons, such as cost, cognitive complaints, and general dislike of pills, became more important in the later years of ET.

Identifying Biomarkers to Select Patients with Early Breast Cancer Suitable for Extended Adjuvant Endocrine Therapy

Postmenopausal women with early oestrogen receptor-positive breast cancer who have received 5 years of endocrine therapy are at increased risk of developing a recurrence. An important clinical question is how to identify women who are at highest (or lowest) risk of a recurrence. The use of prognostic biomarkers allows individualised breast cancer therapy but correct identification of patients who will benefit most from extended endocrine therapy is essential. Several multigene assays have been developed to determine the likelihood of overall recurrence but so far none exist specifically for the prediction of late recurrence. Recent results from large clinical trials have shown that biomarker assays that include clinical information in their tests might be useful to predict and risk stratify patients for late recurrence. However, further research is needed to specifically offer multigene assays for the identification of late recurrence and thus justify routine use of these tests in the clinical setting.

Extended Endocrine Therapy: Is 5 Years Enough?

PURPOSE OF REVIEW

Women with hormone receptor (HR)-positive breast cancer remain at risk for cancer recurrence for decades. In this review, we address recent data regarding the benefits and risks of extended endocrine therapy.

RECENT FINDINGS

Ten years of treatment with either tamoxifen or an aromatase inhibitor resulted in superior disease-free survival compared to 5 years of treatment. However, there are risks associated with extended therapy with either class of medication. Multiparameter genetic tests are in development to individualize the risk of late breast cancer recurrence and predict benefit from extended endocrine treatment. Extended endocrine therapy is a promising strategy to reduce breast cancer recurrence in women with HR-positive breast cancer. This approach should be considered based on individual risk of cancer recurrence compared to potential benefit, comorbidities, and tolerance of therapy.

Endometrial cancer risk in postmenopausal breast cancer patients treated with tamoxifen or aromatase inhibitors

INTRODUCTION

The gynaecological toxicity profile of tamoxifen presents a significant burden to the patients and oncologist as tamoxifen-related side effects result in additional investigations, procedures and referrals. Aromatase inhibitor have been shown to result in significant reduction in gynaecological problems, possibly including endometrial cancer. Areas covered: We reviewed the main breast cancer trials, observation or cohort studies investigating tamoxifen or an aromatase inhibitor to report on endometrial adverse events and cancer. Expert commentary: Evidence for an increase in endometrial cancers with tamoxifen in breast cancer treated patients is now very clear. Aromatase inhibitors have shown to have a beneficial effect on the endometrium. There is an important need for further studies to clearly determine the influence of aromatase inhibitors on the endometrial in tamoxifen-naïve women. The effect of aromatase inhibitors on gynaecological problems may have potentially a very important impact in clinical practice.

Low adherence to upfront and extended adjuvant letrozole therapy among early breast cancer patients in a clinical practice setting

OBJECTIVE

The aim of this study was to investigate the prevalence and causes of early discontinuation and non-adherence to upfront and extended adjuvant letrozole therapy in breast cancer patients.

METHODS

Adherence was assessed using medical charts and longitudinal pharmacy records of 609 patients who initiated adjuvant letrozole between January 2002 and April 2011. A Cox proportional hazards regression model was adopted to identify potential predictors of non-adherence.

RESULTS

The overall adherence rate after 1 year of therapy was 79.5%, with cumulative rates declining to 63.7% after 3 years and 57.1% after 5 years. A significantly lower rate of adherence in the extended adjuvant group was observed compared with the upfront adjuvant group (49.0 vs. 72.5%, p < 0.001). Adverse events (50.4%) were the major cause of early discontinuation, with musculoskeletal pain (73.2%) being the single most cited reason. Additional factors correlating with non-adherence in the upfront adjuvant group included a delay in initiation of adjuvant hormone therapy, breast-conserving surgery, calcium supplements, bisphosphonate therapy and concomitant medication for co-morbidity.

CONCLUSIONS

We observed that approximately 57% of patients fully adhered to letrozole therapy over a 5-year treatment period, and that the adherence to extended letrozole was meaningfully lower than the upfront adjuvant letrozole in a clinical practice setting.

Adjuvant endocrine therapy for women with hormone receptor-positive breast cancer: american society of clinical oncology clinical practice guideline focused update

PURPOSE

To update the ASCO clinical practice guideline on adjuvant endocrine therapy on the basis of emerging data on the optimal duration of treatment, particularly adjuvant tamoxifen.

METHODS

ASCO convened the Update Committee and conducted a systematic review of randomized clinical trials from January 2009 to June 2013 and analyzed three historical trials. Guideline recommendations were based on the Update Committee's review of the evidence. Outcomes of interest included survival, disease recurrence, and adverse events.

RESULTS

This guideline update reflects emerging data on duration of tamoxifen treatment. There have been five studies of tamoxifen treatment beyond 5 years of therapy. The two largest studies with longest reported follow-up show a breast cancer survival advantage with 10-year durations of tamoxifen use. In addition to modest gains in survival, extended therapy with tamoxifen for 10 years compared with 5 years was associated with lower risks of breast cancer recurrence and contralateral breast cancer.

RECOMMENDATIONS

Previous ASCO guidelines recommended treatment of women who have hormone receptor-positive breast cancer and are premenopausal with 5 years of tamoxifen, and those who are postmenopausal a minimum of 5 years of adjuvant therapy with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor (in sequence). If women are pre- or perimenopausal and have received 5 years of adjuvant tamoxifen, they should be offered 10 years total duration of tamoxifen. If women are postmenopausal and have received 5 years of adjuvant tamoxifen, they should be offered the choice of continuing tamoxifen or switching to an aromatase inhibitor for 10 years total adjuvant endocrine therapy.

Clinical validation of the EndoPredict test in node-positive, chemotherapy-treated ER+/HER2- breast cancer patients: results from the GEICAM 9906 trial

Introduction

EndoPredict (EP) is an RNA-based multigene test that predicts the likelihood of distant recurrence in patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2–negative (HER2−) breast cancer (BC) who are being treated with adjuvant endocrine therapy. Herein we report the prospective-retrospective clinical validation of EP in the node-positive, chemotherapy-treated, ER+/HER2− BC patients in the GEICAM 9906 trial.

Methods

The patients (N = 1,246) were treated either with six cycles of fluorouracil, epirubicin and cyclophosphamide (FEC) or with four cycles of FEC followed by eight weekly courses of paclitaxel (FEC-P), as well as with endocrine therapy if they had hormone receptor–positive disease. The patients were assigned to EP risk categories (low or high) according to prespecified cutoff levels. The primary endpoint in the clinical validation of EP was distant metastasis-free survival (MFS). Metastasis rates were estimated using the Kaplan-Meier method, and multivariate analysis was performed using Cox regression.

Results

The molecular EP score and the combined molecular and clinical EPclin score were successfully determined in 555 ER+/HER2− tumors from the 800 available samples in the GEICAM 9906 trial. On the basis of the EP, 25% of patients (n = 141) were classified as low risk. MFS was 93% in the low-risk group and 70% in the high-risk group (absolute risk reduction = 23%, hazard ratio (HR) = 4.8, 95% confidence interval (CI) = 2.5 to 9.5; P < 0.0001). Multivariate analysis showed that, in this ER+/HER2− cohort, EP results are an independent prognostic parameter after adjustment for age, grade, lymph node status, tumor size, treatment arm, ER and progesterone receptor (PR) status and proliferation index (Ki67). Using the predefined EPclin score, 13% of patients (n = 74) were assigned to the low-risk group, who had excellent outcomes and no distant recurrence events (absolute risk reduction vs high-risk group = 28%; P < 0.0001). Furthermore, EP was prognostic in premenopausal patients (HR = 6.7, 95% CI = 2.4 to 18.3; P = 0.0002) and postmenopausal patients (HR = 3.3, 95% CI = 1.3 to 8.5; P = 0.0109). There were no statistically significant differences in MFS between treatment arms (FEC vs FEC-P) in either the high- or low-risk groups. The interaction test results between the chemotherapy arm and the EP score were not significant.

Conclusions

EP is an independent prognostic parameter in node-positive, ER+/HER2− BC patients treated with adjuvant chemotherapy followed by hormone therapy. EP did not predict a greater efficacy of FEC-P compared to FEC alone.

Bilateral breast cancers

An increasingly large proportion of women with unilateral breast cancer are treated with bilateral mastectomy. The rationale behind bilateral surgery is to prevent a second primary breast cancer and thereby to avoid the resultant therapy and eliminate the risk of death from contralateral breast cancer. Bilateral mastectomy has been proposed to benefit women at high risk of contralateral cancer, such as carriers of BRCA1 and BRCA2 mutations, but for women without such mutations, the decision to remove the contralateral breast is controversial. It is important to evaluate the risk of contralateral breast cancer on an individual basis, and to tailor surgical treatment accordingly. On average, the annual risk of contralateral breast cancer is approximately 0.5%, but increases to 3% in carriers of a BRCA1 or BRCA2 mutation. Risk factors for contralateral breast cancer include a young age at first diagnosis of breast cancer and a family history of breast cancer. Contralateral mastectomy has not been proven to reduce mortality from breast cancer, but the benefit of such surgery is not expected to become apparent until the second decade after treatment. An alternative to contralateral mastectomy is adjuvant hormonal therapy (such as tamoxifen), but the extent of risk reduction is smaller (approximately 50%) compared to 95% or more for contralateral mastectomy. This Review focuses on the risk factors for contralateral breast cancer, and discusses the evidence that bilateral mastectomy might reduce mortality in patients with unilateral breast cancer.

From High-Throughput Microarray-Based Screening to Clinical Application: The Development of a Second Generation Multigene Test for Breast Cancer Prognosis

Several multigene tests have been developed for breast cancer patients to predict the individual risk of recurrence. Most of the first generation tests rely on proliferation-associated genes and are commonly carried out in central reference laboratories. Here, we describe the development of a second generation multigene assay, the EndoPredict test, a prognostic multigene expression test for estrogen receptor (ER) positive, human epidermal growth factor receptor (HER2) negative (ER+/HER2−) breast cancer patients. The EndoPredict gene signature was initially established in a large high-throughput microarray-based screening study. The key steps for biomarker identification are discussed in detail, in comparison to the establishment of other multigene signatures. After biomarker selection, genes and algorithms were transferred to a diagnostic platform (reverse transcription quantitative PCR (RT-qPCR)) to allow for assaying formalin-fixed, paraffin-embedded (FFPE) samples. A comprehensive analytical validation was performed and a prospective proficiency testing study with seven pathological laboratories finally proved that EndoPredict can be reliably used in the decentralized setting. Three independent large clinical validation studies (n = 2,257) demonstrated that EndoPredict offers independent prognostic information beyond current clinicopathological parameters and clinical guidelines. The review article summarizes several important steps that should be considered for the development process of a second generation multigene test and offers a means for transferring a microarray signature from the research laboratory to clinical practice.

Contralateral risk-reducing mastectomy in sporadic breast cancer

Recent studies have shown that the number of women undergoing risk-reducing mastectomy has increased rapidly in the USA in the past 15 years. Although a small rise in the number of bilateral risk-reducing procedures has been noted in high-risk gene mutation carriers who have never had breast cancer, this number does not account for the overall increase in procedures undertaken. In patients who have been treated for a primary cancer and are judged to be at high risk of a contralateral breast cancer, contralateral risk-reducing mastectomy is often, but not universally, indicated. However, many patients undergoing contralateral risk-reducing mastectomy might not be categorised as high risk and therefore any potential benefit from this procedure is unproven. At a time when breast-conserving surgery has become more widely used, this sharp increase in contralateral risk-reducing mastectomy is surprising. We have reviewed the literature in an attempt to establish what is driving the increase in this procedure in moderate-to-low-risk populations and to assess its justification in terms of risk-benefit analysis.

Prediction of late disease recurrence and extended adjuvant letrozole benefit by the HOXB13/IL17BR biomarker

BACKGROUND

Biomarkers to optimize extended adjuvant endocrine therapy for women with estrogen receptor (ER)-positive breast cancer are limited. The HOXB13/IL17BR (H/I) biomarker predicts recurrence risk in ER-positive, lymph node-negative breast cancer patients. H/I was evaluated in MA.17 trial for prognostic performance for late recurrence and treatment benefit from extended adjuvant letrozole.

METHODS

A prospective-retrospective, nested case-control design of 83 recurrences matched to 166 nonrecurrences from letrozole- and placebo-treated patients within MA.17 was conducted. Expression of H/I within primary tumors was determined by reverse-transcription polymerase chain reaction with a prespecified cutpoint. The predictive ability of H/I for ascertaining benefit from letrozole was determined using multivariable conditional logistic regression including standard clinicopathological factors as covariates. All statistical tests were two-sided.

RESULTS

High H/I was statistically significantly associated with a decrease in late recurrence in patients receiving extended letrozole therapy (odds ratio [OR] = 0.35; 95% confidence interval [CI] = 0.16 to 0.75; P = .007). In an adjusted model with standard clinicopathological factors, high H/I remained statistically significantly associated with patient benefit from letrozole (OR = 0.33; 95% CI = 0.15 to 0.73; P = .006). Reduction in the absolute risk of recurrence at 5 years was 16.5% for patients with high H/I (P = .007). The interaction between H/I and letrozole treatment was statistically significant (P = .03).

CONCLUSIONS

In the absence of extended letrozole therapy, high H/I identifies a subgroup of ER-positive patients disease-free after 5 years of tamoxifen who are at risk for late recurrence. When extended endocrine therapy with letrozole is prescribed, high H/I predicts benefit from therapy and a decreased probability of late disease recurrence.

Evaluation of factors related to late recurrence--later than 10 years after the initial treatment--in primary breast cancer

BACKGROUND

Breast cancer is associated with a relatively good prognosis. Prognostic factors examined to date are related to early recurrence while those related to late recurrence and their countermeasures remain unclear. Therefore, we examined the factors related to late recurrence.

PATIENTS AND METHODS

From January 1980 to August 2012, 4,774 patients who underwent primary treatment and estrogen (ER) and progesterone receptor (PgR) assessment were enrolled in this study. The patients were divided into two groups, those with a follow-up period <10 years and those without any recurrence at 10 years but who continued follow-up examinations. Recurrence occurred in 711 patients followed up for <10 years and in 51 patients for ≥10 years.

RESULTS

The overall 10-year cumulative disease-free survival rate was 79.5%, and the recurrence rate at ≥10 years was 5.8%. A multivariate analysis revealed that the factors related to late recurrence were PgR positivity and positive nodes. This result differed from that for early recurrence in terms of ER/PgR, Ki-67 index and p53 overexpression.

CONCLUSION

PgR positivity and lymph node metastases significantly correlated with late recurrence. Therefore, it is important to evaluate appropriate measures such as treatment period and treatment regimen for hormone-sensitive patients.

Insulin-like growth factor 1 and musculoskeletal pain among breast cancer patients on aromatase inhibitor therapy and women without a history of cancer

PURPOSE

Musculoskeletal pain is a common side effect of aromatase inhibitors (AIs), the adjuvant hormonal treatment of choice for postmenopausal estrogen-receptor-positive breast cancer. Although the pain is usually attributed to the estrogen depletion associated with AIs, not all women on AIs experience these symptoms. Thus, the goal of this study was to examine whether changes in the insulin-like growth factor (IGF) axis were associated with pain among women initiating AI therapy or a comparison group of women without a history of cancer.

METHODS

Data were analyzed from a cohort study of 52 breast cancer patients for whom AI therapy was planned and 88 women without a history of cancer. Questionnaire data on pain symptoms were collected, and blood was drawn at baseline (prior to AI therapy for patients) and 6 months after baseline. The blood samples were assayed for IGF-1 and IGF-binding protein-3 (IGFBP-3).

RESULTS

While results showed no statistically significant changes in any of the measures across time for either the breast cancer or the comparison group, increases in both IGF-1 concentrations and the IGF-1/IGFBP-3 ratio over the first 6 months of AI treatment were significantly associated with the onset or increase in musculoskeletal pain among the breast cancer patients. Associations between IGF-1, IGFBP-3, and the IGF-1/IGFBP-3 ratio and pain were not observed in the comparison group.

CONCLUSIONS

Although preliminary, findings from this study implicate the IGF axis in the development of AI-associated musculoskeletal pain and represent a first step in developing effective interventions to alleviate this side effect.

An overview of letrozole in postmenopausal women with hormone-responsive breast cancer

Third-generation aromatase inhibitors (AIs) have proven to be superior to tamoxifen in terms of time to disease progression in patients with hormone receptor (HR) positive (HR+) status and, nowadays, are used in the adjuvant and neoadjuvant settings, and first-line therapy for advanced breast cancer. Letrozole is a third generation AI, as are anastrozole and exemestane. In the past, clinical studies had demonstrated that letrozole was effective as a second-line treatment of metastatic breast cancer. In this paper, pharmacokinetic and pharmacodynamic properties of letrozole are reviewed along with its activity in preclinical and clinical settings. Additionally, the results of important clinical trials such as Breast International Group (BIG) 1-98, which tested the optimal initial adjuvant endocrine treatment and the sequential therapy with letrozole and tamoxifen, MA-17 that evaluates the benefits of extended adjuvant therapy, and other important studies in advanced and neoadjuvant disease, are reviewed. Safety comparisons of treatments are also addressed. Interestingly, about 50% of human epidermal growth factor receptor 2-positive (HER2+) breast cancers are HR+. However, HER2 positivity is a marker of antiestrogen treatment resistance. Because of this, a dual treatment is a logical approach when both receptors are overexpressed. The combination of lapatinib and letrozole leads to a significant improvement in the overall disease outcome. Also, the combination of everolimus plus letrozole has been tested in this setting. In fact, the coadministration of both agents seems to increase the efficacy of letrozole in newly-diagnosed HR+ patients. Once resistance to sequential trastuzumab and AI as monotherapy has been found, trastuzumab and letrozole combined in HR+ and HER2+ patients with advanced breast cancer can overcome resistance to both drugs administered as single agents, according to recently reported results.

Approval summary: letrozole (Femara® tablets) for adjuvant and extended adjuvant postmenopausal breast cancer treatment: conversion of accelerated to full approval

On April 30, 2010, the U.S. Food and Drug Administration converted letrozole (Femara®; Novartis Pharmaceuticals Corporation, East Hanover, NJ) from accelerated to full approval for adjuvant and extended adjuvant (following 5 years of tamoxifen) treatment of postmenopausal women with hormone receptor-positive early breast cancer. The initial accelerated approvals of letrozole for adjuvant and extended adjuvant treatment on December 28, 2005 and October 29, 2004, respectively, were based on an analysis of the disease-free survival (DFS) outcome of patients followed for medians of 26 months and 28 months, respectively. Both trials were double-blind, multicenter studies. Both trials were unblinded early when an interim analysis showed a favorable letrozole effect on DFS. In updated intention-to-treat analyses of both trials, the risk for a DFS event was lower with letrozole than with tamoxifen (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.77-0.99; p = .03) in the adjuvant trial and was lower than with placebo (HR, 0.89; 95% CI, 0.76-1.03; p = .12) in the extended adjuvant trial. The latter analysis ignores the interim switch of 60% of placebo-treated patients to letrozole. Bone fractures and osteoporosis were reported more frequently following treatment with letrozole whereas tamoxifen was associated with a higher risk for endometrial proliferation and endometrial cancer. Myocardial infarction was more frequently reported with letrozole than with tamoxifen, but the incidence of thromboembolic events was higher with tamoxifen than with letrozole. Lipid-lowering medications were required for 25% of patients on letrozole and 16% of patients on tamoxifen.

Biologic markers determine both the risk and the timing of recurrence in breast cancer

Breast cancer has a long natural history. Established and emerging biologic markers address overall risk but not necessarily timing of recurrence. 346 adjuvant naïve breast cancer cases from Guy's Hospital with 23 years minimum follow-up and archival blocks were recut and reassessed for hormone-receptors (HR), HER2-receptor and grade. Disease-specific survival (DSS) was analyzed by recursive partitioning. To validate insights from this analysis, gene-signatures (proliferative and HR-negative) were evaluated for their ability to predict early versus late metastatic risk in 683 node-negative, adjuvant naïve breast cancers annotated with expression microarray data. Risk partitioning showed that adjuvant naïve node-negative outcome risk was primarily partitioned by tumor receptor status and grade but not tumor size. HR-positive and HER2-negative (HRpos) risk was partitioned by tumor grade; low grade cases have very low early risk but a 20% fall-off in DSS 10 or more years after diagnosis. Higher grade HRpos cases have risk over >20 years. Triple-negative (Tneg) and HER2-positive (HER2pos) cases DSS events occurred primarily within the first 5 years. Among node-positive cases, only low grade conferred late risk, suggesting that proliferative gene signatures that identify proliferation would be important for predicting early but not late recurrence. Using pooled data from four publicly available data sets for node-negative tumors annotated with gene expression and outcome data, we evaluated four prognostic gene signatures: two proliferation-based and two immune function-based. Tumor proliferative capacity predicted early but not late metastatic risk for HRpos cases. The immune function or HRneg specific signatures predicted only early metastatic risk in Tneg and HER2pos cases. Breast cancer prognostic signatures need to inform both risk and timing of metastatic events and may best be applied within subsets. Current signatures predict for outcome risk within 5 years of diagnosis. Predictors of late risk for HR positive disease are needed.

Use of aromatase inhibitors and bisphosphonates as an anticancer therapy in postmenopausal breast cancer

Breast cancer is a major cause of morbidity and mortality in postmenopausal women worldwide. Reducing the risk of distant disease recurrence is a primary goal of adjuvant endocrine therapy. As we await data from ongoing Phase III comparison trials, an emerging body of evidence demonstrates important differences between third-generation aromatase inhibitors, particularly with respect to potency and prevention of early distant metastases. Furthermore, a growing body of evidence demonstrates anticancer benefits of bisphosphonates in adjuvant breast cancer and other settings. This article outlines the proceedings from an Expert Panel meeting of regionally diverse breast cancer specialists regarding the appropriate use of aromatase inhibitors in postmenopausal hormone-responsive early breast cancer and bisphosphonates as anticancer therapy in adjuvant breast cancer.

American Society of Clinical Oncology clinical practice guideline: update on adjuvant endocrine therapy for women with hormone receptor-positive breast cancer

PURPOSE

To develop evidence-based guidelines, based on a systematic review, for endocrine therapy for postmenopausal women with hormone receptor-positive breast cancer.

METHODS

A literature search identified relevant randomized trials. Databases searched included MEDLINE, PREMEDLINE, the Cochrane Collaboration Library, and those for the Annual Meetings of the American Society of Clinical Oncology (ASCO) and the San Antonio Breast Cancer Symposium (SABCS). The primary outcomes of interest were disease-free survival, overall survival, and time to contralateral breast cancer. Secondary outcomes included adverse events and quality of life. An expert panel reviewed the literature, especially 12 major trials, and developed updated recommendations.

RESULTS

An adjuvant treatment strategy incorporating an aromatase inhibitor (AI) as primary (initial endocrine therapy), sequential (using both tamoxifen and an AI in either order), or extended (AI after 5 years of tamoxifen) therapy reduces the risk of breast cancer recurrence compared with 5 years of tamoxifen alone. Data suggest that including an AI as primary monotherapy or as sequential treatment after 2 to 3 years of tamoxifen yields similar outcomes. Tamoxifen and AIs differ in their adverse effect profiles, and these differences may inform treatment preferences.

CONCLUSION

The Update Committee recommends that postmenopausal women with hormone receptor-positive breast cancer consider incorporating AI therapy at some point during adjuvant treatment, either as up-front therapy or as sequential treatment after tamoxifen. The optimal timing and duration of endocrine treatment remain unresolved. The Update Committee supports careful consideration of adverse effect profiles and patient preferences in deciding whether and when to incorporate AI therapy.

Micrometastatic disease and metastatic outgrowth: clinical issues and experimental approaches

Metastasis from the primary tumor to distant organs is the principal cause of mortality in patients with cancer. While prognostic factors can predict which patients are likely to have their cancer recur, these are not perfect predictors, and some patient's cancers recur even decades after apparently successful treatment. This phenomenon is referred to as dormancy. Data from experimental studies have revealed two categories of metastatic dormancy: cellular dormancy, with solitary cancer cells in cell-cycle arrest; and micrometastatic dormancy, characterized by a balanced state of proliferation and apoptosis, but with no net increase in size. Development of new models and imaging techniques to track the fate of dormant cancer cells is beginning to shed some light on dormancy. Elucidation of the molecular pathways involved in dormancy will advance clinical understanding and may suggest new avenues for treatment to inhibit the revival of these dormant cells, thereby reducing cancer mortality rates.

The expanding use of third-generation aromatase inhibitors: what the general internist needs to know

BACKGROUND

Breast cancer patients represent the largest group of adult cancer survivors in the US. Most breast cancers in women 50 years of age and older are hormone receptor positive. Third generation aromatase inhibitors (AIs) are the newest class of drugs used in treating hormone responsive breast cancer. It is often during start of adjuvant hormone therapy that the breast cancer patient establishes (or reestablishes) close follow-up with their general internist.

OBJECTIVE

Given the large numbers of breast cancer patients in the US and the increasing use of third generation AI's, general internists will need to have a clear understanding of these drugs including their benefits and potential harms. Currently there are three third generation aromatase inhibitors FDA approved for use in the US. All have been shown to be superior to tamoxifen in disease free survival (DFS) in the treatment of both metastatic and early breast cancers.

RESULTS

While the data on side effects is limited, AI (compared to tamoxifen) may result in higher rates of osteoporosis and fractures, more arthralgias, and increased vaginal dryness and dysparuenia. Limited information on their effects on the cardiovascular system and neuro-cognitive function are also available. Patient's receiving adjuvant hormone therapy are generally considered disease free or disease stable and require less intensive monitoring by their breast cancer specialist.

CONCLUSIONS

In situations where patients experience significant negative side effects from AI therapy, discussions to discontinue treatment (and switch to an alternative endocrine therapy) should involve the cancer specialist and take into consideration the patient's risk for breast cancer recurrence and the impact of therapy on their quality of life. In some cases, patients may choose to never initiate AI treatment. In other cases, patients may choose to prematurely discontinue therapy even if therapy is well tolerated. In both settings increased knowledge by the general internists will likely facilitate discussions of risks versus benefits of therapy and possibly improve compliance to adjuvant hormone therapy.

Letrozole: a review of its use in the treatment of postmenopausal women with hormone-responsive early breast cancer

Letrozole (Femara) is a third-generation, nonsteroidal aromatase inhibitor. Adjuvant therapy with letrozole is more effective than tamoxifen in postmenopausal women with hormone-responsive early breast cancer, and extended adjuvant therapy with letrozole after the completion of adjuvant tamoxifen therapy is more effective than placebo in this patient population; letrozole is generally well tolerated. Ongoing trials will help answer outstanding questions regarding the optimal duration of letrozole therapy in early breast cancer and its efficacy compared with other third-generation aromatase inhibitors such as anastrozole. In the meantime, letrozole should be considered a valuable option in the treatment of postmenopausal women with hormone-responsive early breast cancer, both as adjuvant and extended adjuvant therapy.

Tumor dormancy and metastasis

Metastasis--the spread of cancer to distant organs--is responsible for most cancer deaths. Current adjuvant therapy is based on prognostic indicators that stratify patients into defined risk groups. However, some patients believed to have a good prognosis nonetheless develop metastases, in some cases many years after apparently successful treatment of their primary cancer. This period of clinical dormancy leads to many questions about how best to manage patients, including how to better assign risk of late recurrence, how long to monitor patients, and whether some patients will benefit from extended therapy to prevent late recurrences. The development of targeted therapies with fewer side effects is leading to clinical trials aimed at determining the effectiveness of such long-term therapy. However, much remains to be learned about tumor dormancy. Experimental studies are shedding light on biological and molecular mechanisms potentially responsible for tumor dormancy. Emerging research into tumor initiating cells, immunotherapy, and metastasis suppressor genes, may lead to new approaches for targeted antimetastatic therapy to prolong tumor dormancy. An improved understanding of tumor dormancy is needed for better management of patients at risk for late-developing metastases.

Is Endocrine Therapy Really Pleasant? Considerations about the Long-Term Use of Antihormonal Therapy and Its Benefit/Side Effect Ratio

Endocrine therapy has become a key part in the adjuvant treatment of hormone responsive breast cancer. The positive effect on relapse risk reduction is well defined, but therapy is not free from bothersome side effects for which estrogen deprivation accounts to a great extent. Since endocrine therapy is usually prescribed for 5 years or longer to optimally display its protective effect, and because physical strain is missing, good tolerability and safety properties are important, particularly in low-risk patients. While tamoxifen has been the standard adjuvant endocrine treatment with well documented efficiency, it is increasingly replaced by third generation aromatase inhibitors due to their better effectiveness and tolerability. Because tamoxifen holds a risk for life-threatening adverse events such as endometrial cancer, pulmonary embolism, and stroke, its recommended duration of therapy is limited to 5 years, also because extension beyond that time did not produce a measurable advantage. While some side effects are present both with tamoxifen and aromatase inhibitors, differences in side effect profiles are well established. Although side effects of aromatase inhibitor-related therapy usually are mild and common to symptoms of menopause, misconception of the symptoms and their mechanism of action, as well as lack of knowledge about how to handle them, can easily lead to dangerous discontinuation of therapy.

Influence of diet on metastasis and tumor dormancy

Tumor metastasis is responsible for most cancer deaths, and can occur after long periods of tumor dormancy. Information learned from experimental studies on tumor metastasis and dormancy is shedding light on mechanisms responsible and possible therapeutic approaches. 'Seed' (the cancer cell) and 'soil' (the microenvironment of the secondary organ) factors contribute to metastatic outcome. This review considers the possibility that various dietary components may affect both 'seed' and 'soil' compartments, thereby influencing the growth of metastases, and discusses an experimental study on dietary genistein that illustrates this concept. While studies on human diet are complex, the possibility that relatively non-toxic dietary intervention strategies could impact on metastasis and patient survival is attractive and worthy of further study in appropriate experimental models of metastasis and tumor dormancy.