Choosing early adjuvant therapy for postmenopausal women with hormone-sensitive breast cancer: aromatase inhibitors versus tamoxifen

Preventing metastatic recurrence in low-risk ER/PR + breast cancer patients-a retrospective clinical study exploring the evolving challenge of persistence with adjuvant endocrine therapy

PURPOSE

In the genomic era, more women with low-risk breast cancer will forego chemotherapy and rely on adjuvant endocrine therapy (AET) to prevent metastatic recurrence. However, some of these patients will unfortunately relapse. We sought to understand this outcome. Preliminary work suggested that early discontinuation of AET, also known as non-persistence, may play an important role. A retrospective analysis exploring factors related to our breast cancer patients' non-persistence with AET was performed.

METHODS

Women who underwent Oncotype-DX® testing between 2011 and 2014 with minimum 5 years follow-up were included. 'Low risk' was defined as Oncotype score < 26. Outcomes of recurrence and persistence were determined by chart review. Patient, tumor and treatment factors were collected, and persistent versus non-persistent groups compared using multivariable ANOVA and Fisher Chi square exact test.

RESULTS

We identified six cases of distant recurrence among low-risk patients with a median follow-up of 7.7 years. Among them, five of six patients (83%) were non-persistent with AET. The non-persistence rate in our cohort regardless of recurrence was 57/228 (25%). Non-persistent patients reported more severe side effects compared with persistent patients (p = 0.002) and were more likely to be offered a switch in endocrine therapy, rather than symptom-relief (p = 0.006). In contrast, persistent patients were 10.3 times more likely to have been offered symptom-alleviating medications compared with non-persistent patients (p < 0.001). A subset analysis revealed that patients who persisted with therapy had a higher Oncotype-DX® score than patients who discontinued early (p = 0.028).

CONCLUSION

Metastatic recurrence in low-risk breast cancer patients may be primarily due to non-persistence with endocrine therapy. Further work is needed to optimize care for patients who struggle with side effects. To our knowledge, these are the first published data suggesting that Oncotype-DX® score may influence persistence with AET.

Determining the Optimal Cut-Off Values of Serum E2 and FSH for Evaluating the Menopausal Status of Breast Cancer Patients in a Southern Chinese Population

Background

Chemotherapy-induced amenorrhea (CIA) is one of universal phenomena in breast cancer (BC) patients, and it causes difficulties in evaluating the actual menopausal status which is important for the oncologists to choose appropriate treatment. Currently, serum estradiol (E2) and follicle-stimulating hormone (FSH) levels are the most commonly used clinical parameters for the assessment of menopausal status in BC patients. However, the optimal cut-off points of serum E2 and FSH have little been explored in southern Chinese population.

Objective

This study is aimed to determine the optimal cut-off values of the serum E2 and FSH levels for evaluating the menopausal status of BC patients in a southern Chinese population.

Methods

A retrospective analysis was done among a total of 206 patients with BC from a southern Chinese area. The data of serum E2, FSH, and luteinizing hormone (LH) levels were collected and analyzed for the comparison purpose. The receiver-operating curve (ROC) was generated to assess the specificity and sensitivity of the three biomarkers in discriminating the menopausal status of BC patients. The optimal cut-off values were determined according to the Youden index and then compared with the recommended reference values by the Chinese Anti-cancer Association (CACA) and those recommended by the manufacturers.

Results

The areas under the ROC curves (AUCs) of E2, FSH, and LH were 0.846 (95% CI: 0.790-0.903), 0.781 (95% CI: 0.714-0.847) and 0.608 (95% CI: 0.526-0.690), respectively. The optimal cut-off values were 130.0 pg/mL for E2, 23.325 IU/L for FSH, and 11.625 IU/L for LH with a maximum of the Youden index. When E2, FSH, and LH were used in combination for ROC analysis, the AUC increased to 0.847 (95% CI: 0.790-0.904), which was higher than that of any other biomarker alone. In this study, the sensitivity and specificity of E2 and FSH were 91.6% and 73.70% and 94.4% and 58.6%, respectively, in comparison with 85.0% and 75.80% and 76.6% and 65.7% according to the CACA-recommended cut-off points, or 92.5% and 68.7% and 96.3% and 53.5% according to the manufacturer recommended cut-off points.

Conclusion

Considering the sensitivity and specificity of serum E2 and FSH for assessing the menopausal status, the optimal cut-off values determined in the present study were similar to the manufacturer's recommendations, but obviously superior to the cut-off points suggested by CACA. These cut-off points calculated in this study seem to be valuable in southern Chinese population and might be used by clinicians to make a correct medical decision for BC patients who would benefit from endocrine therapy of aromatase inhibitor (AI).

Comparison of breast cancer surrogate subtyping using a closed-system RT-qPCR breast cancer assay and immunohistochemistry on 100 core needle biopsies with matching surgical specimens

Background

Routine clinical management of breast cancer (BC) currently depends on surrogate subtypes according to estrogen- (ER) and progesterone (PR) receptor, Ki-67, and HER2-status. However, there has been growing demand for reduced immunohistochemistry (IHC) turnaround times. The Xpert® Breast Cancer STRAT4* Assay (STRAT4)*, a standardized test for ESR1/PGR/MKi67/ERBB2 mRNA biomarker assessment, takes less than 2 hours. Here, we compared the concordance between the STRAT4 and IHC/SISH, thereby evaluating the effect of method choice on surrogate subtype assessment and adjuvant treatment decisions.

Methods

In total, 100 formalin-fixed paraffin-embedded core needle biopsy (CNB) samples and matching surgical specimens for 98 patients with primary invasive BC were evaluated using the STRAT4 assay. The concordance between STRAT4 and IHC was calculated for individual markers for the CNB and surgical specimens. In addition, we investigated whether changes in surrogate BC subtyping based on the STRAT4 results would change adjuvant treatment recommendations.

Results

The overall percent agreement (OPA) between STRAT4 and IHC/SISH ranged between 76 and 99% for the different biomarkers. Concordance for all four biomarkers in the surgical specimens and CNBs was only 66 and 57%, respectively. In total, 74% of surgical specimens were concordant for subtype, regardless of the method used. IHC- and STRAT4-based subtyping for the surgical specimen were shown to be discordant for 25/98 patients and 18/25 patients would theoretically have been recommended a different adjuvant treatment, primarily receiving more chemotherapy and trastuzumab.

Conclusions

A comparison of data from IHC/in situ hybridization and STRAT4 demonstrated that subsequent changes in surrogate subtyping for the surgical specimen may theoretically result in more adjuvant treatment given, primarily with chemotherapy and trastuzumab.

Effect of angiotensin receptor blockade on prevention and reversion of tamoxifen-resistant phenotype in MCF-7 cells

Tamoxifen (TAM) is a standard adjuvant endocrine therapy in postmenopausal breast cancer patients, but innate or acquired TAM resistance has remained to be a therapeutic challenge for clinicians. The aim of this study was to explore the possible participation of renin-angiotensin system (RAS) in the acquisition of TAM resistance and try to prevent and regress the resistance using an angiotensin II receptor type-1 (AGTR1) blocker, losartan. Establishment of TAM-resistant (TAM-R) cells was accomplished by continuous exposure of MCF-7 cells to 1 μmol/L TAM. MTT (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay was performed to determine cell growth. Moreover, messenger RNA (mRNA) expression levels of AGTR1 and angiotensin II receptor type-2 (AGTR2) were measured by quantitative real-time polymerase chain reaction. A significant increase of AGTR1 and AGTR2 transcripts was observed in TAM-R cells compared to MCF-7 cells. Interestingly, losartan-TAM combination effectively resensitized TAM-R cells to tamoxifen treatment by inducing cell death. Therefore, our findings suggest an important role of RAS in acquired TAM resistance and targeting of RAS by losartan may overcome TAM resistance phenomenon and provide a novel avenue for treatment of resistant breast cancers.

Adherence to adjuvant therapy in post-menopausal breast cancer patients: a review

This review aimed to address the concept of adherence to adjuvant therapy in post-menopausal women. Thirteen studies were included in the review. Study quality was assessed using Critical Appraisal Skills Programme and CONSORT tools. Adherence to adjuvant medication was assessed using a variety of methods. Estimates of adherence rates to adjuvant therapies indicated that of the post-menopausal women prescribed adjuvant therapy, between 15% and 55% were adherent to tamoxifen from 1 to 5 years of follow-up, albeit two studies proposed adherence rates greater than 85%; these data may be flawed due to the methods of data collection. Between 31% and 73% of women were adherent to anastrozole, letrozole or exemestane from 1 year of treatment. These estimates of adherence are based on a variety of reported records including self-report. Current evidence on the assessment of adherence to adjuvant therapies in post-menopausal women indicate that the adherence rates of medication maybe suboptimal and therefore therapeutic efficacy is questionable and may increase the risk of cancer recurrence and reduce disease survival rates. Concerted research is needed to investigate adherence rates, examine patient health beliefs in the medication management of post-menopausal breast cancer patients and also develop new measures to assess adherence with medication.

Toremifene is an effective and safe alternative to tamoxifen in adjuvant endocrine therapy for breast cancer: results of four randomized trials

Compared to tamoxifen, the efficacy and side effects of toremifene in adjuvant endocrine therapy for breast cancer were not very clear. This meta-analysis was conducted to give a more precise estimation of the efficacy and severe side effects of toremifene given in the adjuvant setting in comparison to tamoxifen. The electronic database PubMed was searched for randomized trials comparing toremifene with tamoxifen as adjuvant therapies. Four randomized trials published in three articles were eligible, including 1,890 pooled cases treated with toremifene and 1,857 cases treated with tamoxifen. Compared to patients in tamoxifen group, patients in toremifene group did not have a significantly different overall survival rate (risk ratio (RR): 1.07, 95% confidence interval (CI): 0.97-1.19, P = 0.994 for heterogeneity) or a disease-free survival (DFS) rate (RR: 1.05, 95% CI: 0.95-1.17, P = 0.431 for heterogeneity) at the end of the follow-up time. The rates of thromboembolic events in toremifene group, including deep vein thrombosis (odds ratio (OR): 0.68, 95% CI: 0.40-1.17, P = 0.926 for heterogeneity), cerebrovascular accident (OR: 0.59, 95% CI: 0.32-1.09, P = 0.438 for heterogeneity), and pulmonary embolism (OR: 0.91, 95% CI: 0.42-2.01, P = 0.618 for heterogeneity), were not significantly different from those in tamoxifen group. The rates of endometrial polyps and endometrial cancer between the two groups were almost the same. This meta-analysis suggested that toremifene was as effective as tamoxifen in the adjuvant setting for both perimenopausal and postmenopausal breast cancer patients with similar severe adverse effects to tamoxifen. Toremifene was a convincing and safe change for tamoxifen in adjuvant endocrine therapy.

Excellent outcomes with adjuvant toremifene or tamoxifen in early stage breast cancer

BACKGROUND

Fareston (toremifene) and tamoxifen, both selective estrogen receptor modulators, are therapeutically equivalent treatments for metastatic breast cancer. We hypothesized that toremifene as compared with tamoxifen given as adjuvant therapy for early stage breast cancer would result in equivalent survival with an improved side effect profile, therefore, providing superior therapeutic efficacy.

METHODS

The North American Fareston versus Tamoxifen Adjuvant trial assigned 1813 perimenopausal or postmenopausal women with hormone receptor (HR)-positive invasive breast cancer to adjuvant treatment with either tamoxifen or toremifene. The primary outcomes evaluated were disease-free survival (DFS) and overall survival (OS).

RESULTS

Median follow-up was 59 months. The baseline characteristics of the 2 treatment groups were well-balanced. On the basis of intent-to-treat, 5-year actuarial DFS was not significantly different between tamoxifen and toremifene (91.2% [standard error of the mean [SE] 1.2%] vs 91.2% [SE 1.1%], respectively). Similarly, 5-year actuarial OS was not significantly different between tamoxifen and toremifene (92.7% [SE 1.1%] vs 93.7% [SE 1.0%], respectively). Controlling for patient age, tumor size, and tumor grade, a Cox multivariate survival analysis found no difference between patients randomized to toremifene versus tamoxifen in terms of OS (OR = 0.951; 95% confidence interval [CI], 0.623-1.451, P = .951) or DFS (OR = 1.037; 95% CI, 0.721-1.491, P = .846). Adverse events were similar in the 2 groups.

CONCLUSIONS

Women treated with adjuvant hormonal therapy enjoyed excellent DFS and OS. No significant differences were found between treatment with either tamoxifen or toremifene. Treatment of HR-positive patients with either tamoxifen or toremifene is appropriate.

Genomic and proteomic biomarkers for cancer: a multitude of opportunities

Biomarkers are molecular indicators of a biological status, and as biochemical species can be assayed to evaluate the presence of cancer and therapeutic interventions. Through a variety of mechanisms cancer cells provide the biomarker material for their own detection. Biomarkers may be detectable in the blood, other body fluids, or tissues. The expectation is that the level of an informative biomarker is related to the specific type of disease present in the body. Biomarkers have potential both as diagnostic indicators and monitors of the effectiveness of clinical interventions. Biomarkers are also able to stratify cancer patients to the most appropriate treatment. Effective biomarkers for the early detection of cancer should provide a patient with a better outcome which in turn will translate into more efficient delivery of healthcare. Technologies for the early detection of cancer have resulted in reductions in disease-associated mortalities from cancers that are otherwise deadly if allowed to progress. Such screening technologies have proven that early detection will decrease the morbidity and mortality from cancer. An emerging theme in biomarker research is the expectation that panels of biomarker analytes rather than single markers will be needed to have sufficient sensitivity and specificity for the presymptomatic detection of cancer. Biomarkers may provide prognostic information of disease enabling interventions using targeted therapeutic agents as well as course-corrections in cancer treatment. Novel genomic, proteomic and metabolomic technologies are being used to discover and validate tumor biomarkers individually and in panels.