Assessment of letrozole and tamoxifen alone and in sequence for postmenopausal women with steroid hormone receptor-positive breast cancer: the BIG 1-98 randomised clinical trial at 8·1 years median follow-up

Prognostic and predictive value of androgen receptor expression in postmenopausal women with estrogen receptor-positive breast cancer: results from the Breast International Group Trial 1-98

BACKGROUND

The androgen receptor (AR) is an emerging prognostic marker and therapeutic target in breast cancer. AR is expressed in 60-80% of breast cancers, with higher prevalence among estrogen receptor-positive (ER+) tumors. Androgen treatment inhibits ER signaling in ER+/AR+ breast cancer cell lines, and AR expression is associated with improved survival for this subtype in epidemiologic studies. However, whether AR expression modifies the efficacy of selective ER modulators or aromatase inhibitors for ER+ cancers remains unclear.

METHODS

We evaluated the prognostic and predictive value of AR expression among 3021 postmenopausal ER+ breast cancer patients in the Breast International Group (BIG) trial 1-98. The BIG 1-98 study was a four-armed, double-blind, phase III randomized clinical trial that compared 5 years of tamoxifen or letrozole monotherapy, or sequences of 2 years and 3 years treatment with one drug and then the other. AR expression was measured by immunohistochemistry and the percentage of AR-positive nuclei was quantified. The association between AR expression and prognosis was evaluated using Cox proportional hazards models. Continuous AR-by-treatment interactions were assessed using Subpopulation Treatment Effect Pattern Plots (STEPP).

RESULTS

Eighty-two percent of patients had AR+ (≥ 1%) tumors. Patients with AR+ cancers were more likely to have smaller, lower-grade tumors, with higher expression of ER and PR. AR expression was not associated with breast cancer-free interval (BCFI) (415 events) over a median 8.0 years of follow-up (p = 0.12, log-rank test). In multivariable-adjusted models, AR expression was not associated with BCFI (HR = 1.07, 95% CI 0.83-1.36, p = 0.60). The letrozole versus tamoxifen monotherapy treatment effect did not significantly differ for AR+ tumors (HR = 0.63, 95% CI 0.44-0.75, p = 0.003) and AR- tumors (HR = 0.39, 95% CI 0.21-0.72, p = 0.002) (p-heterogeneity = 0.16). STEPP analysis also suggested no heterogeneity of the treatment effect across the continuum of AR expression.

CONCLUSIONS

AR expression was not associated with prognosis, nor was there heterogeneity of the letrozole versus tamoxifen treatment effect by AR expression. These findings suggest that AR expression may not be an informative biomarker for the selection of adjuvant endocrine therapy for postmenopausal women with ER+ breast cancers.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT00004205, Registered 27 January 2003-Retrospectively registered, https://clinicaltrials.gov/ct2/show/study/NCT00004205 .

EarlyR signature predicts response to neoadjuvant chemotherapy in breast cancer

BACKGROUND

EarlyR gene signature uses ESPL1, SPAG5, MKI67, PLK1 and PGR to classify ER+ breast cancer (ER+ BC) into EarlyR-Low, EarlyR-Int, and EarlyR-High risk strata and is prognostic in patients treated with adjuvant chemotherapy. The ability of EarlyR to predict pathological complete response (pCR) and long-term survival following neoadjuvant chemotherapy (NACT) is evaluated herein.

MATERIALS

The ability of EarlyR gene signature to predict pCR was assessed in publicly available Affymetrix microarray datasets (Cohort A; n = 659; 74 pCR events) derived from NACT-treated ER+ BC patients. Distant relapse-free survival (DRFS) results were analyzed in patients treated with NACT and adjuvant hormone therapy (AHT) (n = 281) and compared with patients treated with AHT alone (n = 455) (Cohort B; n = 736; 142 events).

RESULTS

In cohort A, EarlyR was a significant predictor of pCR (p = 5.8 × 10-11) (EarlyR-Low, n = 400, pCR = 40, 5%; EarlyR-Int, n = 69, pCR = 7, 15% and EarlyR-High, n = 190, pCR = 47, 24%). In EarlyR-Low of Cohort B, the 5-year DRFS was not significantly (p = 0.55) different between NACT + AHT [0.81 (95%CI 0.73-0.90)] and AHT-only [0.85 (95%CI 0.81-0.90)]. In contrast, in EarlyR-High, the 5-year DRFS was higher (p = 0.019) in NACT + AHT [0.81 (95%CI 0.70-0.93)] as compared to AHT-only [0.60 (95%CI 0.51-0.71)].

CONCLUSIONS

High EarlyR is strongly associated with pCR in patients treated with neoadjuvant chemotherapy. EarlyR also predicts poor DRFS outcomes for patients in EarlyR-High not receiving NACT, and improved survival in NACT-treated EarlyR-High patients. EarlyR is not only a prognostic assay but also a predictive assay that identifies patients, who are also likely to respond to chemotherapy.

Adjuvant Letrozole and Tamoxifen Alone or Sequentially for Postmenopausal Women With Hormone Receptor-Positive Breast Cancer: Long-Term Follow-Up of the BIG 1-98 Trial

PURPOSE

Luminal breast cancer has a long natural history, with recurrences continuing beyond 10 years after diagnosis. We analyzed long-term follow-up (LTFU) of efficacy outcomes and adverse events in the Breast International Group (BIG) 1-98 study reported after a median follow-up of 12.6 years.

PATIENTS AND METHODS

BIG 1-98 is a four-arm, phase III, double-blind, randomized trial comparing adjuvant letrozole versus tamoxifen (either treatment received for 5 years) and their sequences (2 years of one treatment plus 3 years of the other) for postmenopausal women with endocrine-responsive early breast cancer. When pharmaceutical company sponsorship ended at 8.4 years of median follow-up, academic partners initiated an observational, LTFU extension collecting annual data on survival, disease status, and adverse events. Information from Denmark was from the Danish Breast Cancer Cooperative Group Registry. Intention-to-treat analyses are reported.

RESULTS

Of 8,010 enrolled patients, 4,433 were alive and not withdrawn at an LTFU participating center, and 3,833 (86%) had at least one LTFU report. For the monotherapy comparison of letrozole versus tamoxifen, we found a 9% relative reduction in the hazard of a disease-free survival event with letrozole (hazard ratio [HR], 0.91; 95% CI, 0.81 to 1.01). HRs for other efficacy end points were similar to those for disease-free survival. Efficacy of letrozole versus tamoxifen for contralateral breast cancer varied significantly over time (0- to 5-, 5- to 10-, and > 10-year HRs, 0.62, 0.47, and 1.35, respectively; treatment-by-time interaction P = .005), perhaps reflecting a longer carryover effect of tamoxifen. Reporting of specific long-term adverse events seemed more effective with national registry than with case-record reporting of clinical follow-up.

CONCLUSION

Efficacy end points continued to show trends favoring letrozole. Letrozole reduced contralateral breast cancer frequency in the first 10 years, but this reversed beyond 10 years. This study illustrates the value of extended follow-up in trials of luminal breast cancer.

Pharmacokinetic evaluation of a transdermal anastrozole-in-adhesive formulation

Background and objective

Anastrozole is a well-established active pharmaceutical ingredient (API) used for the treatment of hormone-sensitive breast cancer (BC) in postmenopausal women. However, treatment with the only available oral formulation is often associated with concentration-dependent serious side effects such as hot flashes, fatigue, muscle and joint pain, nausea, diarrhea, headache, and others. In contrast, a sustained-release system for the local application of anastrozole should minimize these serious adverse drug reactions.

Methods

Anastrozole-in-adhesive transdermal drug delivery systems (TDDS) were developed offering efficient loading, avoidance of inhomogeneity or crystallization of the drug, the desired controlled release kinetics, storage stability, easy handling, mechanical stability, and sufficient stickiness on the skin. In vitro continuous anastrozole release profiles were studied in Franz diffusion cells. In vivo, consecutive drug plasma kinetics from the final anastrozole transdermal system was tested in beagle dogs. For drug analysis, a specific validated liquid chromatography– mass spectrometry method using fragment ion detection was developed and validated.

Results

After efficient drug loading, a linear and sustained 65% drug release from the TDDS over 48 h was obtained. In vivo data showed a favorable anastrozole plasma concentration–time course, avoiding side effect-associated peak concentrations as obtained after oral administration but matching therapeutic plasma levels up to 72 h.

Conclusion

These results provide the basis for establishing the transdermal application of anastrozole with improved pharmacokinetics and drug safety as novel therapeutic approach and promising option to treat human BC by decreasing the high burden of unwanted side effects.

Preparation and optimization of monodisperse polymeric microparticles using modified vibrating orifice aerosol generator for controlled delivery of letrozole in breast cancer therapy

Letrozole (LTZ) is effective for the treatment of hormone-receptor-positive breast cancer in postmenopausal women. In this work, and for the first time, using vibrating orifice aerosol generator (VOAG) technology, monodisperse poly-ε-caprolactone (PCL), and poly (D, L-Lactide) (PDLLA) LTZ-loaded microparticles were prepared and found to elicit selective high cytotoxicity against cancerous breast cells with no apparent toxicity on healthy cells in vitro. Plackett-Burman experimental design was utilized to identify the most significant factors affecting particle size distribution to optimize the prepared particles. The generated microparticles were characterized in terms of microscopic morphology, size, zeta potential, drug entrapment efficiency, and release profile over one-month period. Long-term cytotoxicity of the microparticles was also investigated using MCF-7 human breast cancer cell lines in comparison with primary mammary epithelial cells (MEC). The prepared polymeric particles were monodispersed, spherical, and apparently smooth, regardless of the polymer used or the loaded LTZ concentration. Particle size varied from 15.6 to 91.6 µm and from 22.7 to 99.6 µm with size distribution (expressed as span values) ranging from 0.22 to 1.24 and from 0.29 to 1.48 for PCL and PDLLA based microparticles, respectively. Upon optimizing the manufacture parameters, span was reduced to 0.162-0.195. Drug entrapment reached as high as 96.8%, and drug release from PDLLA and PCL followed a biphasic zero-order release using 5 or 30% w/w drug loading in the formulations. Long-term in vitro cytotoxicity studies indicated that microparticles formulations significantly inhibited the growth of MCF-7 cell line over a prolonged period of time but did not have toxic effects on the normal breast epithelial cells.

Comparison of Antifungal Azole Interactions with Adult Cytochrome P450 3A4 versus Neonatal Cytochrome P450 3A7

Adult drug metabolism is dominated by cytochrome P450 3A4 (CYP3A4), which is often inhibited by antifungal azole drugs, resulting in potential alterations in drug metabolism and adverse drug/drug interactions. In the fetal and neonatal stages of life, the 87% identical cytochrome P450 3A7 (CYP3A7) is expressed but not CYP3A4. Azole antifungals developed for adults are also used in neonates, assuming they interact similarly with both enzymes, but systematic information is lacking. Herein a method was developed for generating recombinant purified CYP3A7. Thirteen different azoles were then evaluated for binding and inhibition of purified human CYP3A4 versus CYP3A7. All imidazole-containing azoles bound both enzymes via coordination to the heme iron and inhibited both with IC50 values ranging from 180 nM for clotrimazole to the millimolar range for imidazole itself. Across this wide range of potencies, CYP3A4 was consistently inhibited more strongly than CYP3A7, with clotrimazole being the least selective (1.5-fold) inhibitor and econazole the most selective (12-fold). Observations for 1,2,4-triazole-containing azoles were more varied. Most bound to CYP3A4 via coordination to the heme iron, but several also demonstrated evidence of a distinct binding mode at low concentrations. However, only posaconazole inhibited CYP3A4. Of the triazoles, only posaconazole inhibited CYP3A7, again less potently than CYP3A4. Spectral evidence for binding was weak or nonexistent for all triazoles. Overall, although the details of binding interactions do vary, the same azole compounds inhibit both enzymes, albeit with weaker interactions with CYP3A7 compared with CYP3A4.

Endocrine therapy for breast cancer in the primary care setting

The treatment of hormone-positive breast cancer (bca) is a rapidly evolving field. Improvement in the understanding of the mechanisms of action and resistance to anti-hormonal therapy has translated, in the past decade, into multiple practice-changing clinical trials, with the end result of increased survivorship for patients with all stages of hormone-positive cancer. The primary care physician will thus play an increasing role in the routine care, surveillance, and treatment of issues associated with anti-hormonal therapy. The aim of the present review was to provide a focused description of the issues relevant to primary care, while briefly highlighting recent advances in the field of anti-hormonal therapy.

Key Points

■ Hormone-positive bca is the most prevalent form of bca and, compared with the other subtypes, is usually associated with better survival.■ Survivorship has significantly increased for all stages of hormone-positive bca, making the primary care physician a key player in the care of affected patients.■ The two most common classes of anti-hormonal agents used in these patients are selective estrogen receptor modulators and aromatase inhibitors. Each class of medication is associated with signature side effects.■ Within the past decade, multiple novel estrogen receptor blockers (for example, fulvestrant) and agents aimed at circumventing resistance to endocrine therapy [inhibitors of cyclin-dependent kinase 4/6 and of mtor (the mechanistic target of rapamycin)] have gained clinical ground. Understanding their side effects will be increasingly relevant to primary care physicians.■ Multidisciplinary care is always encouraged in the care of cancer patients receiving anti-hormonal therapy.

Fibronectin expression is upregulated by PI-3K/Akt activation in tamoxifen-resistant breast cancer cells

Fibronectin (FN) plays important roles in the EMT in a variety of cancer cell types. However, the mechanism by which FN expression is regulated in tamoxifen-resistant (TamR) breast cancer cells has not yet been fully elucidated. Aberrant FN expression was associated with poor prognosis in patients with luminal type A breast cancer. In addition, FN was upregulated in TamR cells. To investigate the mechanism by which FN expression is regulated, we assessed the levels of phosphorylated Akt, JNK, and STAT3 and found that they were all increased in TamR cells. Induction of FN expression was dampened by LY294002 or AKT IV in TamR cells. Furthermore, FN expression was increased by constitutively active (CA)-Akt overexpression in tamoxifen-sensitive MCF7 (TamS) cells and colony formation of TamR cells was blocked by AKT IV treatment. Taken together, these results demonstrate that FN expression is upregulated through the PI-3K/Akt pathway in tamoxifen-resistant breast cancer cells.

Optimizing adjuvant endocrine therapy for early ER+ breast cancer: An update for surgeons

INTRODUCTION

The optimal duration of adjuvant endocrine therapy in early ER + breast cancer has been controversial. This article aims to provide an overview of the evidence.

METHODS

A search of the literature was conducted via MEDLINE using appropriate keywords. Eligible studies were screened and relevant articles were selected for this report.

RESULTS

Studies investigating the role of extended adjuvant tamoxifen beyond 5 years have revealed mixed results depending on the proportion of node positivity. In postmenopausal women, aromatase inhibitors (AIs) for 5 years are superior to tamoxifen. Extending the use of AIs beyond 5 years seem to reduce the risk of relapse in postmenopausal women with node positive disease. The addition of bisphosphonates to counteract AI-related osteopenia may further improve overall and disease-free survival. Women younger than 40 years seem to benefit from ovarian suppression combined with tamoxifen or exemestane.

CONCLUSIONS

An individualised approach is required for every patient. The adverse effects of endocrine therapy should be weighed against the potential benefits of extended therapy to better inform decision-making.

Cost-effectiveness of monitoring endoxifen levels in breast cancer patients adjuvantly treated with tamoxifen

PURPOSE

Breast cancer is the most common malignancy in women worldwide. Recurrence rates in breast cancer are considered to be dependent on the serum concentration of endoxifen, the active metabolite of tamoxifen. The goal of this study is to investigate the cost-effectiveness of periodically monitoring serum concentrations of endoxifen in adjuvant estrogen receptor alfa (ERα) positive breast cancer patients treated with tamoxifen in the Netherlands.

METHODS

A Markov model with disease-free survival (DFS), recurrent disease (RD), and death states was constructed. The benefit of drug monitoring was modeled via a difference in the fraction of patients achieving adequate serum concentrations. Robustness of results to changes in model assumptions were tested through deterministic and probabilistic sensitivity analyses.

RESULTS

Monitoring of endoxifen added 0.0115 quality-adjusted life-years (QALYs) and saved € 1564 per patient in the base case scenario. Deterministic sensitivity analysis demonstrated a large effect on the incremental cost-effectiveness ratio (ICER) of the differences in costs and utilities between the DFS and RD states. Probabilistic sensitivity analysis showed that the probability of cost-effectiveness at a willingness to pay of € 0 per quality-adjusted life-year (QALY) was 89.8%.

CONCLUSIONS

Based on this model, monitoring of endoxifen in adjuvant ERα + breast cancer patients treated with tamoxifen is likely to add QALYs and save costs from a healthcare payer perspective. We advise clinicians to consider integrating serum endoxifen concentration monitoring into standard adjuvant tamoxifen treatment of ERα + breast cancer patients.

Are Providers and Patients Following Hormonal Therapy Guidelines for Patients Over the Age of 70? The Influence of CALGB 9343

BACKGROUND

The Cancer and Leukemia Group B (CALGB) 9343 clinical trial proved that omission of radiotherapy (RT) in patients 70 and older with T1cN0M0, estrogen receptor-positive tumors who undergo breast conservation therapy (BCT) and receive 5 years of endocrine therapy (ET) had no change in overall survival, distant disease-free survival, or breast preservation. We examined our institution's practice with this patient subset.

PATIENTS AND METHODS

A single-institution retrospective chart review was performed on patients 70 years and older with T1N0M0, estrogen receptor-positive tumors, and who underwent BCT between April 2010 and October 2015.

RESULTS

A total of 123 patients met inclusion criteria: 46% received RT and 73% received ET. The ET group had a mean age of 76.2 years, whereas the non-ET group had a mean age of 80.2 years (P = .00006). Race did not influence if patients received ET (P = .4). In patients who received ET, mean age at time of diagnosis for those that completed 5 years of therapy was 75.5 years, whereas those who stopped therapy early had a mean age of 77.6 years (P = .053). In patients who received ET but stopped early, reasons for cessation included side-effect profile (67%), death (22%), and noncompliance (11%). Of the 27% of patients that did not receive ET, 62% were not offered therapy, 24% refused, and 14% were lost to postoperative follow-up.

CONCLUSION

Increasing age showed significant association to not receive ET. Contraindication to ET and provider's assessment of minimal benefit are the most common reasons why patients are not prescribed ET. If patients are non-compliant with ET, RT should be reconsidered.

Integration of Clinical Variables for the Prediction of Late Distant Recurrence in Patients With Estrogen Receptor-Positive Breast Cancer Treated With 5 Years of Endocrine Therapy: CTS5

Purpose Estimating risk of late distant recurrence (DR) is an important goal for managing women with hormone receptor-positive breast cancer after 5 years of endocrine treatment without recurrence. We developed and validated a simple clinicopathologic tool (Clinical Treatment Score post-5 years [CTS5]) to estimate residual risk of DR after 5 years of endocrine treatment. Patients and Methods The ATAC (Arimidex, Tamoxifen, Alone or in Combination) data set (N = 4,735) was used to create a prognostic score for post-5-year risk of DR. Validity of CTS5 (ATAC) was tested in the BIG 1-98 data set (N = 6,711). Time to late DR, 5 years after finishing scheduled endocrine therapy, was the primary end point. Cox regression models estimated the prognostic performance of CTS5 (ATAC). Results CTS5 (ATAC) was significantly prognostic for late DR in the ATAC cohort (hazard ratio, 2.47; 95% CI, 2.24 to 2.73; P < .001) and BIG 1-98 validation cohort (hazard ratio, 2.07; 95% CI, 1.88 to 2.28; P < .001). CTS5 (ATAC) risk stratification defined in the training cohort as low (< 5% DR risk, years 5 to 10), intermediate (5% to 10%), or high (> 10%) identified 43% of the validation cohort as low risk, with an observed DR rate of 3.6% (95% CI, 2.7% to 4.9%) during years 5 to 10. From years 5 to 10, 63% of node-negative patients were low risk, with a DR rate of 3.9% (95% CI, 2.9% to 5.3%), and 24% with one to three positive nodes were low risk, with a DR rate of 1.5% (95% CI, 0.5% to 3.8%). A final CTS5 for future use was derived from pooled data from ATAC and BIG 1-98. Conclusion CTS5 is a simple tool based on information that is readily available to all clinicians. CTS5 was validated as highly prognostic for late DR in the independent BIG 1-98 study. The final CTS5 algorithm identified 42% of women with < 1% per-year risk of DR who could be advised of the limited potential value of extended endocrine therapy.

Long-term effect of exemestane therapy on bone mineral density supported by bisphosphonates: Results of 5-year adjuvant treatment in postmenopausal women with early-stage breast cancer

PURPOSE

Unlike anastrozole, the effect of long-term exemestane (EXE) therapy on bone mineral density (BMD) is still unknown. We assessed changes in BMD from baseline to 5 years of EXE treatment.

METHODS

Postmenopausal women with endocrine-responsive breast cancer receiving EXE as adjuvant therapy were enrolled in this study. EXE was administered for 5 years. The BMD of the lumbar spine (LS) and femoral neck (FN) was assessed by dual-energy X-ray absorptiometry at baseline and after 6 months and 1, 2, 3, 4, 5 and 6 years. Oral bisphosphonate (Bis) treatment was initiated when patients were diagnosed with osteoporosis with a T-score of -2.5 or lower.

RESULTS

Eighty-one patients were enrolled in the study between 2005 and 2010. The median follow-up period was 54.9 months. Forty-two patients were administered Bis. Overall, the BMD of the LS increased by 7.3% from baseline and that of the FN increased by 3.4% with 5 years of EXE treatment. At the sixth year (i.e. 1 year after the treatment), BMD of the LS increased by 7.2% and that of the FN increased by 5.7%. Furthermore, the BMD of the FN increased by 12.0% in patients treated upfront with Bis and by 1.2% in those not treated with Bis (P = 0.0262). Fractures developed in nine patients (11.1%) and seven (8.6%) had fragility fractures.

CONCLUSION

Oral Bis improves BMD of the FN in patients with osteoporosis. Five-year EXE treatment with proper addition of Bis helps maintain the BMD of the LS and FN at the sixth year.

Obesity and breast cancer - Role of estrogens and the molecular underpinnings of aromatase regulation in breast adipose tissue

One in eight women will develop breast cancer over their lifetime making it the most common female cancer. The cause of breast cancer is multifactorial and includes hormonal, genetic and environmental cues. Obesity is now an accepted risk factor for breast cancer in postmenopausal women, particularly for the hormone-dependent subtype of breast cancer. Obesity, which is characterized by an excess accumulation of body fat, is at the origin of chronic inflammation of white adipose tissue and is associated with dramatic changes in the biology of adipocytes leading to their dysfunction. Inflammatory factors found in the breast of obese women considerably impact estrogen signaling, mainly by driving changes in aromatase expression the enzyme responsible for estrogen production, and therefore promote tumor formation and progression. There is thus a strong link between adipose inflammation and estrogen biosynthesis and their signaling pathways converge in obese patients. This review describes how obesity-related factors can affect the risk of hormone-dependent breast cancer, highlighting the different molecular mechanisms and metabolic pathways involved in aromatase regulation, estrogen production and breast malignancy in the context of obesity.

Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells

Aromatase inhibitor (AI) resistance is a major obstacle in the treatment of estrogen receptor-positive breast cancer. Everolimus (EVE) ameliorates AI-resistant breast cancer and is therefore used in cancer treatment. However, some patients show resistance to EVE. Here, we used 30 clones of long-term estrogen-deprived (LTED) MCF-7 cells as a model of AI-resistant breast cancer. We examined changes in protein phosphatase type 2A (PP2A) and cancerous inhibitor of PP2A (CIP2A), a negative regulator of PP2A, in LTED cells treated with EVE. In LTED cells with high sensitivity to EVE, CIP2A expression decreased at low EVE concentrations; however, in LTED cells poorly sensitive to EVE, CIP2A and PP2A did not change upon exposure to EVE. Therefore, we hypothesized that there is a relation between expression of CIP2A and sensitivity to EVE. Knockdown of CIP2A increased the sensitivity to EVE in three clones poorly sensitive to EVE. Additionally, we found that treatment with FSK, which activates PP2A, increased the sensitivity of the cells to EVE. Our data point to CIP2A and PP2A as novel therapeutic targets for AI-resistant breast cancer.

Current Status of Extended Adjuvant Endocrine Therapy in Early Stage Breast Cancer

OPINION STATEMENT

In the past decade, several endocrine treatment regimens have been developed for the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer, including tamoxifen, aromatase inhibitors (AI), or a combination of these. The standard duration of adjuvant endocrine treatment has been 5 years for a long time. Nevertheless, the high number of recurrences occurring after 5 years suggested that extended endocrine therapy could further improve outcome, which led to the start of several randomized clinical trials investigating the effects of extended use of endocrine therapy. The extended duration of tamoxifen has been shown to improve disease-free survival and overall survival in the ATLAS and aTTom trials. However, in postmenopausal women, AIs have been shown to be more effective when compared with tamoxifen. Based hereon, it is recommended that adjuvant endocrine therapy in postmenopausal women with early breast cancer should include an AI. Recently, the DATA, IDEAL, and NSABP B42 trials showed that extended adjuvant endocrine therapy with AIs beyond 5 years in postmenopausal women with early breast cancer did reduce the occurrence of secondary breast tumors, but had no or only a small impact on distant metastasis free survival. Furthermore, toxicity of adjuvant AIs led to gradually decreasing compliance rates and long-term toxicities to non-breast cancer-related deaths. Therefore, we suggest considering extended adjuvant treatment only in women with high-risk early breast cancer who tolerate treatment well.

Clinicopathologic features of hormone-receptor-positive breast cancer patients with late recurrence

The number of long-term breast cancer survivors with a risk of late recurrence is increasing. Hormone-receptor-positive patients have greater risks of late recurrence. Although several studies demonstrated that extended adjuvant endocrine therapy reduces the incidence of late recurrence, it remains unclear which hormone-receptor-positive patients have greater risks of late recurrence. Hormone-receptor-positive breast cancer patients were retrospectively selected from the prospective database of primary breast cancer patients treated at Keio University Hospital from January 1989 to December 2003. Late recurrence was defined as initial recurrence after 5 years from the initial surgery. We evaluated the clinicopathologic features of breast cancer patients with late recurrence. At a median follow-up of 10.9 years (range, 5.1-23.8), 371 patients had no recurrence, 90 had early recurrence (within 5 years), and 83 had late recurrence. Multivariate analysis revealed that >4 involved lymph nodes were significant risk factors for late recurrence (P < .001), whereas 1-3 positive nodes were not. Endocrine therapy significantly reduced the incidence of late recurrence (P < .001). After menopause, adjuvant therapy with aromatase inhibitors resulted in longer disease-free survival than tamoxifen (10-year disease-free survival: 97.6% vs 89.7%, P = .0955). High nodal involvement was significantly correlated with late recurrence in hormone-receptor-positive breast cancer patients. Hormone-receptor-positive breast cancer patients who receive adjuvant endocrine therapy with tamoxifen alone might be candidates for extended endocrine therapy.

Improved overall survival over recent decades in patients with hormone-receptor-positive, HER2-negative breast cancer: a single-center retrospective analysis of prognostic factors

Background

Hormone receptor (HR)-positive HER2-negative breast cancer (BC) rates and associated mortality have been increasing among Japanese women. It is unclear whether the prognosis of these patients has improved.

Methods

We retrospectively analyzed 1806 Japanese women with operable invasive HR-positive HER2-negative BC, who underwent complete resection at the National Cancer Center Hospital East between July 1992 and December 2010. We investigated whether overall survival (OS) and recurrence-free survival (RFS) had improved by comparing the 4-year periods 1992-96, 1997-2001, 2002-06, and 2007-10. The prognostic factors were evaluated using uni- and multivariate analyses.

Results

The number of ER- and PgR-positive cancers had increased over the years (P < 0.001). Tumor sizes and numbers of involved lymph nodes both gradually decreased (P < 0.001 for both). OS and RFS of all patients significantly improved in each of the periods analyzed: 5-year OS was 92.6%, 94.8%, 95.4% and 97.6% (P < 0.001, Log-rank), and 5-year RFS was 82.1%, 82.8%, 88.6% and 94.5% (P < 0.001) in 1992-96, 1997-2001, 2002-06 and 2007-10, respectively. In multivariate analysis, the history of adjuvant AI and that of TAM had positive-correlation with RFS.

Conclusions

The prognosis for HR-positive HER2-negative BC patients after surgical therapy has improved, resulting in longer OS and RFS across the study periods. These changes could be associated with early detection of tumor and history of hormone therapy.

Use of Breast Imaging After Treatment for Locoregional Breast Cancer (AFT-01)

BACKGROUND

Annual mammography is recommended after breast cancer treatment. However, studies suggest its under-utilization for Medicare patients. Utilization in the broader population is unknown, as is the role of breast magnetic resonance imaging (MRI). Understanding factors associated with imaging use is critical to improvement of adherence to recommendations.

METHODS

A random sample of 9835 eligible patients receiving surgery for stages 2 and 3 breast cancer from 2006 to 2007 was selected from the National Cancer Database for primary data collection. Imaging and recurrence data were abstracted from patients 90 days after surgery to 5 years after diagnosis. Factors associated with lack of imaging were assessed using multivariable repeated measures logistic regression with generalized estimating equations. Patients were censored for death, bilateral mastectomy, new cancer, and recurrence.

RESULTS

Of 9835 patients, 9622, 8702, 8021, and 7457 patients were eligible for imaging at surveillance years 1 through 4 respectively. Annual receipt of breast imaging declined from year 1 (69.5%) to year 4 (61.0%), and breast MRI rates decreased from 12.5 to 5.8%. Lack of imaging was associated with age 80 years or older and age younger than 50 years, black race, public or no insurance versus private insurance, greater comorbidity, larger node-positive hormone receptor-negative tumor, excision alone or mastectomy, and no chemotherapy (p < 0.005). Receipt of breast MRI was associated with age younger than 50 years, white race, higher education, private insurance, mastectomy, chemotherapy, care at a teaching/research facility, and MRI 12 months before diagnosis (p < 0.05).

CONCLUSION

Under-utilization of mammography after breast cancer treatment is associated with sociodemographic and clinical factors, not institutional characteristics. Effective interventions are needed to increase surveillance mammography for at-risk populations. ClinicalTrials.gov Identifier: NCT02171078.

Mammographic density: a potential monitoring biomarker for adjuvant and preventative breast cancer endocrine therapies

Increased mammographic density (MD) has been shown beyond doubt to be a marker for increased breast cancer risk, though the underpinning pathobiology is yet to be fully elucidated. Estrogenic activity exerts a strong influence over MD, which consequently has been observed to change predictably in response to tamoxifen anti-estrogen therapy, although results for other selective estrogen receptor modulators and aromatase inhibitors are less consistent. In both primary and secondary prevention settings, tamoxifen-associated MD changes correlate with successful modulation of risk or outcome, particularly among pre-menopausal women; an observation that supports the potential use of MD change as a surrogate marker where short-term MD changes reflect longer-term anti-estrogen efficacy. Here we summarize endocrine therapy-induced MD changes and attendant outcomes and discuss both the need for outcome surrogates in such therapy, as well as make a case for MD as such a monitoring marker. We then discuss the process and steps required to validate and introduce MD into practice as a predictor or surrogate for endocrine therapy efficacy in preventive and adjuvant breast cancer treatment settings.

Are previous episodes of bacterial vaginosis a predictor for vaginal symptoms in breast cancer patients treated with aromatase inhibitors?

Objective To estimate the prevalence of vaginal symptoms in postmenopausal women with breast cancer exposed to aromatase inhibitors, and to investigate if the risk of vaginal symptoms is associated with previous episodes of bacterial vaginosis. Methods Patients from Rigshospitalet and Herlev University Hospital, Denmark, were identified through the register of Danish Breast Cancer Cooperation Group and 78 patients participated in the study. Semiquantitave questionnaires and telephone interview were used to assess the prevalence of vaginal symptoms and previous episode(s) of bacterial vaginosis. Multivariable logistic regression models were used to assess the association between vaginal symptoms and previous episodes of bacterial vaginosis. Results Moderate to severe symptoms due to vaginal itching/irritation were experienced by 6.4% (95% CI: 2.8-14.1%), vaginal dryness by 28.4% (95% CI: 19.4-39.5%), and dyspareunia by 23.1% (95% CI: 11.0-42.1%). Patients with earlier episodes of bacterial vaginosis had an increased risk of vaginal dryness when exposed to a treatment with an aromatase inhibitor, adjusted OR 5.5 (95% CI 1.3-21.6). Conclusion A considerable number of patients exposed to aromatase inhibitor have vaginal symptoms and the risk is highest among patients with earlier episodes of bacterial vaginosis.

Concurrent new drug prescriptions and prognosis of early breast cancer: studies using the Danish Breast Cancer Group clinical database

BACKGROUND

Myriad reports suggest that frequently used prescription drugs alter the viability of breast cancer cells in pre-clinical studies. Routine use of these drugs, therefore, may impact breast cancer prognosis, and could have important implications for public health.

METHODS

The Danish Breast Cancer Group (DBCG) clinical database provides high-quality prospectively collected data on breast cancer diagnosis, treatment, and routine follow-up for breast cancer recurrence. Individual-level linkage of DBCG data to other population-based and medical registries in Denmark, including the Danish National Prescription Registry, has facilitated large population-based pharmacoepidemiology studies. A unique advantage of using DBCG data for such studies is the ability to investigate the association of drugs with breast cancer recurrence rather than breast cancer mortality - which may be misclassified - or all-cause mortality. Here we summarize findings from pharmacoepidemiological studies, based on DBCG data, on the association between routinely used prescription drugs and risk of breast cancer recurrence.

RESULTS

Our findings suggest that concurrent use of glucocorticoids, ACE inhibitors, aspirin, NSAIDs, selective COX-2 inhibitors, digoxin, and opioids has little impact on breast cancer recurrence. Similarly, patients who use SSRIs concurrently with tamoxifen treatment are not at increased risk of recurrence. In contrast, post-diagnostic use of simvastatin, a lipophilic statin, correlates with a decreased risk of breast cancer recurrence, providing a rationale for a prospective randomized clinical trial investigating simvastatin as an adjuvant therapy for breast cancer.

CONCLUSION

As a whole, findings of pharmacoepidemiological studies based on DBCG data provide reassurance to physicians and healthcare personnel who provide supportive care during and after cancer (including prescriptions for comedications) and to breast cancer survivors for whom the risk of breast cancer recurrence is a major concern.

Aurora kinase A as a possible marker for endocrine resistance in early estrogen receptor positive breast cancer

BACKGROUND

Cell culture studies have disclosed that the mitotic Aurora kinase A is causally involved in both tamoxifen and aromatase inhibitor resistant cell growth and thus may be a potential new marker for endocrine resistance in the clinical setting.

MATERIAL AND METHODS

Archival tumor tissue was available from 1323 Danish patients with estrogen receptor (ER) positive primary breast cancer, who participated in the Breast International Group (BIG) 1-98 trial, comparing treatment with tamoxifen and letrozole and both in a sequence. The expression of Aurora A was determined by immunohistochemistry in 980 tumors and semi quantitively scored into three groups; negative/weak, moderate and high. The Aurora A expression levels were compared to other clinico-pathological parameters and outcome, defined as disease-free survival (DFS) and overall survival (OS).

RESULTS

High expression of Aurora A was found in 26.9% of patients and moderate in 57.0%. High expression was significantly associated with high malignancy grade and HER2 amplification. High Aurora A expression was significantly more frequent in ductal compared to lobular carcinomas. We found no significant association between Aurora A expression and DFS or OS and no evidence of interaction between Aurora A expression and benefits from tamoxifen versus letrozole.

CONCLUSIONS

Aurora A expression in breast tumors was associated with high malignancy grade III and with HER2 amplification. A trend as a prognostic factor for OS was found in patients with high Aurora A expression. No predictive property was observed in this study with early breast cancer.

Adjuvant endocrine monotherapy for postmenopausal early breast cancer patients with hormone-receptor positive: a systemic review and network meta-analysis

BACKGROUND

In patients with hormone receptor-positive postmenopausal of early stage breast cancer, adjuvant endocrine monotherapies include letrozole, anastrozole, exemestane, toremifene and tamoxifen. But the optimum regimen remains controversial.

METHODS

PubMed, Cochrane Database and ClinicalTrials.gov were systematically reviewed of abstract for randomized-controlled trials (RCTs) to assess the efficacy of tamoxifen, letrozole, exemestane, anastrozle and toremifene for postmenopausal patients with hormone-receptor positive (HR+), who have not received prior therapy for early stage breast cancer. The outcomes were measured by disease-free survival (DFS) and overall survival (OS). We evaluated relative hazard ratios (HRs) for death of different therapies by combination hazard ratios for death of included trials. The SUCRA values were used to evaluate the rankings of efficacy for these monotherapies.

RESULTS

A total of fourteen studies including 19,517 patients in our research were absorbed and estimated. The superiority of efficacy for DFS were 5-year letrozole and 10-year tamoxifen (SUCRA values 0.743/0.657) in all comparisons. A more efficient SUCRA values for OS were 5-year Exemestane, 5-year letrozole and 10-year tamoxifen (0.756/0.677/0.669).

CONCLUSIONS

Clinically important differences exist between commonly prescribed different adjuvant endocrine monotherapy regimens for both efficacy and acceptability in favor of exemestane and letrozole. 10-year tamoxifen for early breast cancer patients is noninferior to 5-year anastrozle, and might be the best choice where aromatase inhibitors (AIs) are not easy to acquire.

Forty years of landmark trials undertaken by the Danish Breast Cancer Cooperative Group (DBCG) nationwide or in international collaboration

BACKGROUND

Over the past 40 years the Danish Breast Cancer Cooperative Group (DBCG) has made significant contributions to improve outcome and to make treatment of patients with early breast cancer more tolerable through nationwide and international trials evaluating loco-regional and systemic treatments. These trials have been instrumental to establish standards for the treatment of early breast cancer.

METHODS

The DBCG 82 trials had a global impact by documenting that the significant gain in loco-regional recurrence from postmastectomy radiation added to systemic therapy was associated with a reduction in distant recurrence and mortality in high-risk pre- and postmenopausal patients. The DBCG trials comparing breast conserving surgery and radiotherapy with mastectomy and more recently the trial of internal mammary node irradiation also had a major impact of practice. The trials initiated by the DBCG 40 years ago on tamoxifen and cyclophosphamide based chemotherapy became instrumental for the development of adjuvant systemic therapy not only due to their positive results but by sharing these important data with other members of the Early Breast Cancer Trialist' Collaborative Group (EBCTCG). Trials from the DBCG have also been important for highlighting the relative importance of anthracyclines and taxanes in the adjuvant setting. Furthermore, DBCG has made a major contribution to the development of aromatase inhibitors and targeted adjuvant treatment for human epidermal growth factor receptor 2 positive breast cancers.

RESULTS

The substantial impact of these treatment improvements is illustrated by a 46.7% 10-year overall survival of early breast cancer patients treated in 1978-1987 compared to 71.5% for patients treated 2008-2012.

CONCLUSIONS

The trials conducted and implemented by the DBCG appear to have a major impact on the substantial survival improvements in breast cancer.

Fractures in a nationwide population-based cohort of users of breast cancer hormonal therapy

PURPOSE

Although users of aromatase inhibitors have higher total fracture risk in some randomized trials, little is known about their risk outside of clinical trials or in older higher-risk cohorts.

METHODS

In a population-based retrospective cohort study, we identified all older US Medicare D prescription drug insurance plan-enrolled women who had initial breast cancer surgery in 2006-2008 and began hormonal therapy (an aromatase inhibitor (AI) or tamoxifen) within the subsequent year. Total nonvertebral and hip fractures through 2012 were identified using a validated algorithm. The association of fracture outcomes with hormonal therapy type was assessed using competing risk regression models that accounted for differences in measured baseline covariates. Treatment assignment bias was reduced using inverse probability of treatment weighting computed from propensity scores.

RESULTS

Among 23,378 women taking hormonal therapy (23.2% aged 80 or over), there were 3000 total and 436 hip fractures. Although AI users were younger and had lower comorbidity, after propensity score weighting, these and other covariates were balanced. Total nonvertebral risk was higher for users of AIs compared with tamoxifen, HR 1.11 (1.02-1.21), but the small increase in risk for hip fracture was not statistically significant, HR 1.04 (0.84-1.30).

CONCLUSIONS

Although total nonvertebral fracture risk was higher among AI users, differences in hip fractures were not significant in a large population-based cohort of older women.

IMPLICATIONS FOR CANCER SURVIVORS

Use of aromatase inhibitors by older women is associated with high risk for nonvertebral fracture that is increased compared with use of tamoxifen. Fracture risk should be assessed among patients taking these medications.

Translational opportunities for broad-spectrum natural phytochemicals and targeted agent combinations in breast cancer

Breast cancer (BC) prevention and therapy in the context of life-style risk factors and biological drivers is a major focus of developmental therapeutics in oncology. Obesity, alcohol, chronic estrogen signaling and smoking have distinct BC precipitating and facilitating effects that may act alone or in combination. A spectrum of signaling events including enhanced oxidative stress and changes in estrogen-receptor (ER)-dependent and -independent signaling drive the progression of BC. Breast tumors modulate ERα/ERβ ratio, upregulate proliferative pathways driven by ERα and HER2 with a parallel loss and/or downregulation of tumor suppressors such as TP53 and PTEN which together impact the efficacy of therapeutic strategies and frequently lead to emergence of drug resistance. Natural phytochemicals modulate oxidative stress, leptin, integrin, HER2, MAPK, ERK, Wnt/β-catenin and NFκB signaling along with regulating ERα and ERβ, thereby presenting unique opportunities for both primary and combinatorial interventions in BC. In this regard, this article focuses on critical analyses of the evidence from multiple studies on the efficacy of natural phytochemicals in BC. In addition, areas in which the combinations of such effective natural phytochemicals with approved and/or developing anticancer agents can be translationally beneficial are discussed to derive evidence-based inference for addressing challenges in BC control and therapy.

Identifying accessible prognostic factors for breast cancer relapse: a case-study on 405 histologically confirmed node-negative patients

BACKGROUND

Histologically, node-negative breast cancer generally have a good prognosis. However, 10 to 30% of the cases present local relapses or metastasis. This group of people has high chances of remission if detected early. The aim of this study is to identify financial affordability for developing countries to adjust treatment.

METHODS

We selected 405 patients with histologically confirmed node-negative breast cancer in our institution between January 2001 and December 2003. Patients with metastasis were excluded. The statistical analysis was conducted using SPSS ver. 18 (SPSS, Inc., Chicago, Illinois).

RESULTS

The medial age was 51 years old. The medial tumor size was 35.4 mm. Clinically, 67.2% of the patients were staged cT2 and 63.2%, cN1i. Breast conservation was achieved in 41% of cases. In the histologic examination, the medial size was 30 mm. Grade III tumors were found in 50.1% of patients and positive hormonal receptors in 53.4%. The mean number of lymph nodes was 14. Eight patients had neoadjuvant chemotherapy. Adjuvant locoregional radiation and adjuvant chemotherapy were prescribed respectively in 70.6 and 64.4% of cases. 59.7% had adjuvant hormonal therapy. The follow-up showed 17.7% cases of relapse either locally or in a metastatic way in a mean time of 57.4 months. The disease-free survival at 5 years was 82.1%, and the overall survival for the same period was 91.5%. The histologic tumor size and the grade and number of lymph node dissected were shown to be influencing the disease-free survival. Radiation therapy and hormone therapy showed improved disease-free survival and overall survival.

CONCLUSION

Our study found interesting results that may help personalize the treatment especially for patient living in underdeveloped countries, but further studies are needed to evaluate those and more accessible prognostic factors for a more accessible healthcare.

The SIRT2 Deacetylase Stabilizes Slug to Control Malignancy of Basal-like Breast Cancer

Overabundance of Slug protein is common in human cancer and represents an important determinant underlying the aggressiveness of basal-like breast cancer (BLBC). Despite its importance, this transcription factor is rarely mutated in BLBC, and the mechanism of its deregulation in cancer remains unknown. Here, we report that Slug undergoes acetylation-dependent protein degradation and identify the deacetylase SIRT2 as a key mediator of this post-translational mechanism. SIRT2 inhibition rapidly destabilizes Slug, whereas SIRT2 overexpression extends Slug stability. We show that SIRT2 deacetylates Slug protein at lysine residue K116 to prevent Slug degradation. Interestingly, SIRT2 is frequently amplified and highly expressed in BLBC. Genetic depletion and pharmacological inactivation of SIRT2 in BLBC cells reverse Slug stabilization, cause the loss of clinically relevant pathological features of BLBC, and inhibit tumor growth. Our results suggest that targeting SIRT2 may be a rational strategy for diminishing Slug abundance and its associated malignant traits in BLBC.

Identification of miRNAs as biomarkers for acquired endocrine resistance in breast cancer

Therapies targeting estrogen receptor α (ERα) including tamoxifen, a selective estrogen receptor modulator (SERM) and aromatase inhibitors (AI), e.g., letrozole, have proven successful in reducing the death rate for breast cancer patients whose initial tumors express ERα. However, about 40% of patients develop acquired resistance to these endocrine treatments. There is a critical need to develop sensitive circulating biomarkers that accurately identify signaling pathways altered in breast cancer patients resistant to endocrine therapies. Serum miRNAs have the potential to serve as biomarkers of the progression of endocrine-resistant breast cancer due to their cancer-specific expression and stability. Exosomal transfer of miRNAs has been implicated in metastasis and endocrine-resistance. This review focuses on miRNAs in breast tumors and in serum, including exosomes, from breast cancer patients that are associated with resistance to tamoxifen since it is best-studied.

Risk Factors and Preventions of Breast Cancer

Breast cancer is the second leading cause of cancer deaths among women. The development of breast cancer is a multi-step process involving multiple cell types, and its prevention remains challenging in the world. Early diagnosis of breast cancer is one of the best approaches to prevent this disease. In some developed countries, the 5-year relative survival rate of breast cancer patients is above 80% due to early prevention. In the recent decade, great progress has been made in the understanding of breast cancer as well as in the development of preventative methods. The pathogenesis and tumor drug-resistant mechanisms are revealed by discovering breast cancer stem cells, and many genes are found related to breast cancer. Currently, people have more drug options for the chemoprevention of breast cancer, while biological prevention has been recently developed to improve patients' quality of life. In this review, we will summarize key studies of pathogenesis, related genes, risk factors and preventative methods on breast cancer over the past years. These findings represent a small step in the long fight against breast cancer.

Preoperative Endocrine Therapy

Purpose of Review

Pre-operative endocrine therapy can be used to down-stage large or locally advanced breast cancers in ER+ disease. In the last four decades, it has evolved from a treatment perceived as an alternative to surgery for those too unfit to undergo surgery or chemotherapy, to the present day where it is a valuable and valid option in the treatment of postmenopausal women with ER-rich (Allred score 7–8, or > 50% staining for ER) breast cancer.

Recent Findings

Emerging data from the metastatic setting is translating into neoadjuvant trials, utilising dual endocrine targeting or combinations of endocrine agents and other targeted drugs, including those acting against components of the PI3K pathway and the cell cycle. The routine use of peri-operative endocrine therapy in all ER+ tumours may help to yield important long-term prognostic information, and guide adjuvant endocrine therapy.

Summary

Pre-operative endocrine therapy is an exciting and evolving area with emerging new approaches. In this review, established evidence and emerging data on its applications are discussed.

Endocrine sensitivity of estrogen receptor-positive breast cancer is negatively correlated with aspartate-β-hydroxylase expression

Although prognostic markers for early estrogen receptor (ER)‐positive breast cancer have been extensively developed, predictive markers for adjuvant endocrine therapy are still lacking. Focusing on the mechanisms underlying endocrine resistance, we investigated whether the endocrine sensitivity of ER‐positive breast cancer cells was correlated with the expression of aspartate‐β‐hydroxylase (ASPH), which is involved in the development of hepatocellular carcinoma. ASPH expression in ER‐positive and tamoxifen‐resistant breast cancer cells was upregulated by the MAPK and phosphoinositide‐3 kinase (PI3K) pathways, which both play pivotal roles in endocrine resistance. In the clinical setting, ASPH expression was negatively correlated with recurrence‐free survival of luminal B breast cancer patients that received adjuvant endocrine therapy, but not in patients that did not receive adjuvant endocrine therapy. Luminal B breast cancer is one of the intrinsic molecular subtypes identified by the Prediction Analysis of Microarray 50 (PAM50) multiple gene classifier, and because of its poor response to endocrine therapy, chemotherapy in addition to endocrine therapy is generally required after surgical resection. Our results suggest that the endocrine sensitivity of luminal B breast cancer can be assessed by examining ASPH expression, which promotes the consideration of a prospective study on the association between ASPH expression at the mRNA and protein levels in luminal B breast cancer and subsequent response to endocrine therapy.

Estradiol suppresses phosphorylation of ERα serine 167 through upregulation of PP2A in breast cancer cells

Aromatase inhibitors (AIs) are effective endocrine therapeutics for postmenopausal women with estrogen receptor (ER)α-positive breast cancer. However, the efficacy of the treatment is often limited by the onset of AI resistance, owing to the phosphorylation of ERα serine 167 (Ser167). Previous studies have indicated that hyperactivation of the phosphoinositide-3 kinase/RAC serine/threonine-protein kinase signaling pathway occurs in AI-resistant breast cancer models, which coincides with elevated levels of ERα phosphorylation at Ser167. The tumor suppressor serine/threonine-protein phosphatase 2A (PP2A) regulates the phosphatidylinositol 3-kinase/RAC serine/threonine-protein kinase signaling pathway. A previous study indicated that PP2A inhibition decreased ERα Ser167 phosphorylation and estradiol (E₂)-independent cell growth. The present study investigated the potential relevance of PP2A in E₂ deprivation-resistant MCF-7 cells. E₂ depletion reduced the susceptibility of MCF-7 cells to inhibitors of mechanistic target of rapamycin (mTOR) and significantly increased ERα Ser167 phosphorylation and decreased expression of PP2A. Conversely, long-term E₂-deprived (LTED) MCF-7 cells, a model of AI-resistant breast cancer, exhibited decreased ERα Ser167 phosphorylation and further upregulation of PP2A in E₂-containing medium. The PP2A activator forskolin (FSK) significantly inhibited LTED cell proliferation by increasing the effect of everolimus (Eve), an mTOR inhibitor. In summary, the present study provides further evidence that PP2A represents a therapeutic target for AI-resistant breast cancer.

A high level of estrogen-stimulated proteins selects breast cancer patients treated with adjuvant endocrine therapy with good prognosis

BACKGROUND

Adjuvant endocrine therapy has significantly improved survival of estrogen receptor α (ER)-positive breast cancer patients, but around 20% relapse within 10 years. High expression of ER-stimulated proteins like progesterone receptor (PR), Bcl-2 and insulin-like growth factor receptor I (IGF-IR) is a marker for estrogen-driven cell growth. Therefore, patients with high tumor levels of these proteins may have particularly good prognosis following adjuvant endocrine therapy.

PATIENTS AND METHODS

Archival tumor tissue was available from 1323 of 1396 Danish breast cancer patients enrolled in BIG 1-98, a randomized phase-III clinical trial comparing adjuvant letrozole, tamoxifen or a sequence of the two drugs. Immunohistochemical staining for ER, HER-2, PR, Bcl-2 and IGF-IR was performed and determined by Allred scoring (ER, PR and Bcl-2) or HercepTest (HER-2 and IGF-IR).

RESULTS

Data on all five markers were available from 969 patients with ER-positive, HER-2-negative tumors. These patients were classified in ER activity groups based on the level of PR, Bcl-2 and IGF-IR. High ER activity profile was found in 102 patients (10.5%) and compared with the remaining patients, univariate and multivariate analysis revealed HR (95% CI) and p values for disease-free survival (DFS) of 2.00 (1.20-3.22), 0.008 and 1.70 (1.01-2.84), 0.04 and for the overall survival (OS) of 2.33 (1.19-4.57), 0.01 and 1.90 (0.97-3.79), 0.06, respectively. The high ER activity profile did not disclose difference in DFS or OS according to treatment with tamoxifen or letrozole (p = .06 and .09, respectively).

CONCLUSIONS

Stratifying endocrine-treated patients in ER activity profile groups disclosed that patient with high ER activity profile (10.5%) had significantly longer DFS and OS, and the profile was an independent marker for DFS. High ER activity is a marker for estrogen-driven tumor growth. We suggest further analyses to disclose whether the ER activity profile or other markers associated with estrogen-driven growth may be used to identify ER-positive high-risk breast cancer patients who can be spared adjuvant chemotherapy.

Vascular function in breast cancer survivors on aromatase inhibitors: a pilot study

PURPOSE

Aromatase inhibitors (AI) have been shown to reduce breast cancer-related mortality in women with estrogen positive (ER+) breast cancer. The use of AIs, however, has been associated with higher rates of hypertension, hyperlipidemia, and cardiovascular (CV) events.

METHODS

A cross-sectional study of 25 healthy postmenopausal women and 36 women with curative intent breast cancer on an AI was performed to assess endothelial dysfunction, an indicator of risk for CV events. Consented subjects underwent vascular testing using the HDI/Pulse Wave CR-2000 Cardiovascular Profiling System and the EndoPAT2000 system.

RESULTS

Mean age was 61.7 and 59.6 years (cases, controls). Most subjects were Caucasian and overweight. Controls had a lower mean systolic blood pressure (128.6 mmHg vs. 116.2 mmHg, p = 0.004). Median estradiol levels were reduced in cases (2 vs. 15 pg/ml, p < 0.0001). EndoPAT ratio (0.8 vs. 2.7, p < 0.0001) was significantly reduced in cases as compared to controls. Median large artery elasticity (12.9 vs. 14.6 ml/mmHg × 10, p = 0.12) and small artery elasticity (5.2 vs. 7.0 ml/mmHg × 100, p = 0.07) were also reduced though not statistically significant. There was no correlation between use of chemotherapy, radiation therapy, type of AI, or duration of AI use and endothelial function. When adjusting for differences in blood pressure, results remained significant.

CONCLUSION

Breast cancer cases on AIs have reductions in endothelial function, a predictor of adverse CV disease.

IMPACT

Vascular function changes in breast cancer cases on AIs compared to postmenopausal women. Further work is needed to evaluate vascular changes over time.