Benefit Of Tamoxifen Research Articles

Use of antipsychotics with tamoxifen

IntroductionBipolar disorder is a frequent and serious psychiatric disease. Antipsychotics are habitually required for its management especially during an acute manic episode. The association of cancer with bipolar disorder may impact psychiatric management. The choice of the adequate antipsychotic drug remains a challenge in this case. The clinical benefit of tamoxifen is obtained after the hepatic metabolism with cytochrome P450 2D6 which generates endoxifen, the potent metabolite of tamoxifen. Evidence has emerged that antipsychotics may potentially inhibit the CYP2D6. Study data supporting this interaction are rare.ObjectivesIn this work, we aimed to illustrate the modalities of care of bipolar disorder in a patient receiving tamoxifen.MethodsPresentation of a clinical case of a patient treated by Tamoxifen for her breast cancer and who was admitted in our department for acute mania with psychotics features, followed by a literature review.ResultsA 53-year-old woman with past history of breast cancer diagnosed in 2018, treated with lumpectomy and radiation, followed by tamoxifen. She has been admitted in 2019 in our department for an acute mania with psychotics features. Olanzapine was prescribed with good clinical evolution. The psychiatric and oncologic status of the patient was stable after one year under tamoxifen and olanzapine.ConclusionsPsychiatrists must be aware that some of the prescribed medications co-administered with tamoxifen interfere with the CYP2D6 function, which may potentially increase the risk of breast cancer recurrence. A close collaboration between psychiatrists and oncologists is required to adapt therapeutic protocols.

Abstract PS5-09: Tumour infiltrating lymphocytes of prognostic value in different molecular breast cancer subgroups and as a suggestive predictive factor for adjuvant tamoxifen benefit in premenopausal patients after 30 years follow-up

Abstract BACKGROUND The molecular breast cancer subgroups comprise diverse immune biology; for human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC) and triple-negative breast cancer (TNBC) abundance of tumour infiltrating lymphocytes (TILs) have been shown to indicate good prognosis and could predict pathological complete response after neoadjuvant chemotherapy. In contrast, the clinical relevance of TILs in estrogen receptor-positive/HER2-negative (ER+/HER2-) tumours is not settled. We primary aimed to analyse the prognostic effect of TILs on BC-free interval (BCFi) in premenopausal patients, stratified by molecular subgroups. The secondary aim was to investigate the predictive value of TILs on tamoxifen benefit. METHODS Archival tissue from primary tumours was collected from patients included in the SBII:2pre trial. In this study, 564 premenopausal women were randomised between two years of adjuvant tamoxifen or no systemic treatment regardless of hormone-receptor status. TILs were scored on whole tissue sections and the tumours were divided into ER+/HER2- (n = 255), HER2+ (n = 65) and TNBC (n = 95) molecular subgroups by immunohistochemistry and in situ hybridisation (ISH). The prognostic value of TILs was evaluated in patients allocated to no systemic therapy, whose tumours were successfully scored for TILs and had IHC/ISH data for generating molecular subgroups (n = 221). All patients with ER+ tumours and successfully annotated TILs were considered for prediction of tamoxifen benefit (n = 321). The median follow-up was 28 years and the prognostic and predictive analyses were performed by cumulative incidence curves and Cox regression analyses. RESULTS TILs were successfully scored in 477 tumours with available ER status and the proportion of low (<10%), intermediate (10-49%) and high (≥50%) TILs were 52% (n = 248), 33% (n = 157) and 15% (n = 72), respectively. High infiltration of TILs was a favourable prognostic factor (univariable analysis: hazard ratioBCFi (HRBCFi) 0.40; 95% confidence interval (CI) 0.22-0.71; P = 0.002) (Table 1). The results were essentially the same in the ER+/HER2- molecular subgroup (HRBCFi 0.40; 95% CI 0.14-1.09; P = 0.07). Adjuvant tamoxifen improved prognosis in patients with ER+ tumours and TILs levels <50%, (univariable analysis HRBCFi 0.63; 95% CI 0.47-0.84; P = 0.002), which was not observed in patients displaying high immune infiltration (≥50%) (HRBCFi 0.84; 95% CI (0.24-2.86); P = 0.77). However, evidence for differential effect of tamoxifen in categories of TILs, i.e. interaction, was weak. CONCLUSIONS We demonstrate a long-term favorable prognostic value of levels of TILs in a cohort of premenopausal BC patients. This effect seems to be extended to the ER+/HER2- subgroup. A beneficial effect of tamoxifen in ER+ patients was observed in patients with tumours of low TILs infiltration as compared to patients with tumours of high immune infiltration, but we could not confirm a treatment predictive effect. Table 1. Uni- and multivariable Cox regression analyses of BCFi and OS (control arm)Univariable*MultivariableEndpointBCFiOSBCFiOSHR (95% CI); P valueTILs, category***All molecular subgroups(n = 221)(n = 213)Low (Ref.)1.001.001.001.00Intermediate1.10 (0.78-1.54); 0.611.26 (0.88-1.80); 0.210.61 (0.40-0.93); 0.020.65 (0.41-1.02); 0.06High0.40 (0.22-0.71); 0.0020.52 (0.29-0.95); 0.030.22 (0.11-0.43); <0.0010.23 (0.11-0.48); <0.001ER+/HER2-(n = 136)(n = 135)Low (Ref.)1.001.001.001.00Intermediate1.02 (0.63-1.64); 0.941.02 (0.61-1.71); 0.950.69 (0.42-1.15); 0.160.65 (0.37-1.15); 0.14High0.40 (0.14-1.09); 0.070.55 (0.20-1.52); 0.250.20 (0.06-0.60); 0.0040.30 (0.10-0.96); 0.04HER2+(n = 38)(n = 35)Low (Ref.)1.001.001.001.00Intermediate1.47 (0.62-3.49); 0.391.07 (0.45-2.56); 0.880.47 (0.14-1.60); 0.230.38 (0.11-1.31); 0.13High0.28 (0.08-0.97); 0.050.27 (0.08-0.96); 0.040.06 (0.01-0.56); 0.010.05 (0.01-0.39); 0.005TNBC(n = 47)(n = 43)Low (Ref.)1.001.001.001.00Intermediate0.76 (0.31-1.87); 0.551.24 (0.49-3.14); 0.650.59 (0.21-1.67); 0.321.02 (0.34-3.11); 0.97High0.27 (0.08-0.88); 0.030.44 (0.14-1.36); 0.160.38 (0.11-1.39); 0.150.59 (0.16-2.26); 0.44*Stratified by Region**The following variables were included in multivariable analysis: age (≥40 vs.<40 years), nodal status (0 vs.1-3 vs. ≥4), tumour size (>20 mm vs. ≤20), NHG (1 vs. 2 vs. 3), ER (positive vs. negative), PR (positive vs. negative), HER2 (positive vs. negative), LVI (present vs. absent) and TILs (high vs. intermediate vs. low). Stratified by Region.*** TILs were categorised as low: <10%, intermediate: 10-49% and high: ≥50%Abbreviations: BCFi breast cancer free-interval, OS overall survival, TILs tumour infiltrating lymphocytes, HER2 human epidermal growth factor receptor 2, TNBC triple-negative breast cancer, NHG nottingham histological grade, ER estrogen receptor, PR progesterone receptor, HR hazard ratio, CI confidence interval Citation Format: Christine Lundgren, Pär-Ola Bendahl, Maria Ekholm, Mårten Fernö, Carina Forsare, Ute Krüger, Bo Nordenskjöld, Olle Stål, Lisa Rydén. Tumour infiltrating lymphocytes of prognostic value in different molecular breast cancer subgroups and as a suggestive predictive factor for adjuvant tamoxifen benefit in premenopausal patients after 30 years follow-up [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-09.

Abstract GS4-09: Correlative studies of the breast cancer index (HOXB13/IL17BR) and ER, PR, AR, AR/ER ratio and Ki67 for prediction of extended endocrine benefit: A trans-aTTom study

Abstract Background: Several biomarkers such as estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR) and Ki67 have been implicated in the pathogenesis and/or as prognostic biomarkers of breast cancer, and are utilized to determine treatment. Given the heterogeneity of response to endocrine therapy, however, predictive biomarkers are critical to better individualize patient care. Previous results from the Trans-aTTom study demonstrated that the Breast Cancer Index HOXB13/IL17BR [BCI (H/I)] biomarker significantly predicts extended endocrine benefit from 10 vs 5y of tamoxifen. In this correlative study, the predictive activity of BCI (H/I) was compared with ER, PR, AR and Ki67 protein expression in node positive patients treated in the aTTom trial. Methods: Patients with available tumor tissue and biomarker analyses were included. ER, PR, AR and Ki67 were centrally assessed by immunohistochemistry (IHC) utilizing tissue microarrays. BCI gene expression analysis by RT-PCR was performed blinded to clinical outcome. Multivariate Cox models adjusting for age, tumor size, tumor grade and HER2 status were used to assess the significance of the interaction between treatment and each biomarker as continuous variables. 17-year risk of recurrence, as a function of each continuous biomarker, was estimated from Cox models in each of the 2 treatment arms. Results: Analysis of 789 HR+, N+ patients showed a weak negative correlation between BCI (H/I) and ER, PR, and AR expression whereas Ki67 and the AR/ER ratio showed no correlation (ER, cor=−0.18; PR, cor=−0.25; AR, cor=−0.14; Ki67, cor=0.04; AR/ER ratio, cor=0.02). The interaction between BCI (H/I) and extended tamoxifen treatment was significant (p=0.014). In addition, analysis of risk of recurrence as a function of continuous BCI (H/I) demonstrated that the magnitude in the reduction in recurrence risk with extended tamoxifen correlated with increasing H/I levels. In contrast, interaction P values were nonsignificant (ER, p=0.829; PR, p=0.659; AR, p=0.783; Ki67, p=0.865; AR/ER ratio, p=0.835) and the magnitude of endocrine benefit did not correlate with expression levels of any of other biomarkers. Conclusion: Results from this post-hoc analysis of the Trans-aTTom study demonstrated that whereas BCI(H/I) is a significant predictive biomarker of endocrine response, analysis of ER, PR, AR, Ki67 and AR/ER expression showed no interaction with treatment, and lacked the ability to predict benefit of extended tamoxifen in HR+ early stage breast cancer. These results add to the growing body of evidence that BCI (H/I) is distinct in its ability to predict benefit from therapy and interrogates distinct tumor biology that is not captured by other traditional biomarkers. Citation Format: Dennis C Sgroi, Kai Treuner, Yi Zhang, Tammy Piper, Ranelle Salunga, Ikhlaaq Ahmed, Lucy Doos, Sarah Thornber, Karen J Taylor, Elena F Brachtel, Sarah Pirrie, Catherine A Schnabel, Daniel W Rea, John MS Bartlett. Correlative studies of the breast cancer index (HOXB13/IL17BR) and ER, PR, AR, AR/ER ratio and Ki67 for prediction of extended endocrine benefit: A trans-aTTom study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS4-09.

MCM3 upregulation confers endocrine resistance in breast cancer and is a predictive marker of diminished tamoxifen benefit

Resistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in the cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317), and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Interestingly, the MCM3 levels did not affect the efficacy of growth inhibitory by CDK4/6 inhibitors. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic marker adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.

Clinical practice to address tamoxifen nonadherence.

The primary and secondary benefits of tamoxifen as adjuvant therapy in women with hormone-receptor-positive breast cancer are substantial: a 1% decrease in the risk of death each year for 10years with each additional year of treatment during the first 5years. Considerable data, however, indicate that these benefits are lost to many patients because of treatment nonadherence. Nonadherence is examined within the framework of the Common-Sense Model of Self-Regulation to describe patients' models of disease and treatment that organize their thinking and behavior, and the crucial role of the practitioner in addressing and altering these models. Common patient education and social communications about patients' hormone-receptor-positive breast cancer and tamoxifen treatment promote an acute disease paradigm in which cancer occurs within specific locations and is either present or absent. We recommend that clinicians communicate the concepts of hormone-receptor-positive breast cancer as follows: i. a non-dichotomous systemic disorder entailing a treatment goal of homeostasis and disease quiescence and ii. a disorder undetectable by currently available tests in subclinical states. Equally important, the clinician can provide a comprehensive picture of the well-documented secondary effects of tamoxifen, noting in particular the beneficial effects. Specific action plans, grounded in individual patient understanding, can be developed and reinforced, in an ongoing process that validates and integrates patient values and goals as they change over time.

Duct carcinoma in situ: A personal perspective.

In the recent past, DCIS was a rare diagnosis established by biopsy of palpable breast masses or nipple changes. Mammography increased the frequency of a DCIS diagnosis by 20×resulting in a tsunami of small circa 10mm lesions detected only by mammography. The impact of pathologic technique in examining and characterizing such lesions is reviewed, and the development of algorithms incorporating prognostic factors and histology based on serial sequential processing techniques are described and contrasted with those which relied on tissue sampling. The development of the initial clinical trails of irradiation all demonstrated the significant benefit of irradiation but none could identify subsets with a more favorable outcome. The latter was precluded by their common practice of tissue sampling: Size could not be calculated and margin width and microinvasion could not be reliable demonstrated. Multigene signature assays are increasingly being utilized, most prominently Oncotype DCIS. However, these assays must be interpreted in conjunction with the limitations set forth in the validating studies-in the case of Oncotype DCIS-the size, margin width, and grade which defined the baseline study (E5194). Tamoxifen and other anti-hormonal agents (aromatase inhibitor therapy) have been shown to have a limited impact on ipsilateral recurrence which makes their use given their morbidities problematic. Such interventions do impact the frequency of contralateral occult in situ and invasive lesions. In the one study which permitted a comparison of local recurrence in irradiated vs nonirradiated breast, there was no added benefit of Tamoxifen in irradiated breasts. Some are attempting to identify a low-risk subset of DCIS which can be treated without surgical re-excision for margins or adjuvant irradiation. These studies are in progress but surrogates identified within the Van Nuys prospective series defined by grade and inadequate margins (≤1mm) would suggest a significant recurrence and progression rate. DCIS remains a work in progress both in terms of classification and treatment. However, limited our progress in these areas we have certainly advanced from the oft-proclaimed mantra: "Radiation and Tamoxifen are standard of care."

Survival benefit of tamoxifen in male breast cancer: prospective cohort analysis

BackgroundDue to the lack of prospective data, current treatment of male breast cancer (MBC) is based on information obtained from retrospective analysis or by extrapolation from studies on female patients. In this prospectively enrolled cohort study, we retrospectively examined the survival effect of tamoxifen in MBC patients.MethodsIn this prospectively enrolled cohort study, 448 patients with MBC were treated between May 2009 and June 2018. The primary endpoint was disease-free survival (DFS).ResultsBetween May 2009 and June 2018, 448 men with breast cancer were identified, with a median age at diagnosis of 69 years (range 27–96 years). The median follow-up was 39 months (range 3–89 months). Most tumours were larger than 20 mm; invasive ductal carcinoma was of no special histological type and with an intermediate grade of differentiation. Almost half of the men were diagnosed with positive axillary lymph nodes (43.5%). Hormone receptor (HR) positivity was observed in 98.4% of the patients. Notably, DFS among men who did not receive tamoxifen was significantly reduced as compared with those who underwent tamoxifen therapy (P = 0.002). The recurrence rate and mortality in the group of patients without and with tamoxifen treatment were 18.2% and 11.2%, respectively. The most common localisation of metastases was the bone. After adjustment for prognostic factors, we found that tamoxifen was found to reduce the recurrence rate by 68% (hazard ratio HR = 0.32; 95% confidence interval, CI: 0.14–0.74).ConclusionsTamoxifen treatment was associated with improved DFS for MBC patients.Clinical trial registrationDRKS00009536.

Knowledge of Potential Harms and Benefits of Tamoxifen among Women Considering Breast Cancer Preventive Therapy.

Tamoxifen reduces breast cancer incidence in women at increased risk, but may cause side effects. We examined women's knowledge of tamoxifen's potential harms and benefits, and the extent to which knowledge reflects subjective judgments of awareness and decision quality. After a hospital appointment, 408 (55.7%) women at increased risk of breast cancer completed a survey assessing objective knowledge about the potential benefit (risk reduction) and harms (endometrial cancer, thromboembolic events, and menopausal side effects) of tamoxifen, and subjective tamoxifen knowledge and decisional quality. Two hundred fifty-eight (63.2%) completed a 3-month follow-up survey. Sixteen percent (15.7%) of participants recognized the potential benefit and three major harms of using tamoxifen. These women were more likely to have degree-level education [vs. below degree level; OR, 2.24; 95% confidence interval (CI), 1.11-4.55] and good numeracy (vs. poor numeracy; OR, 5.91; 95% CI, 1.33-26.19). Tamoxifen uptake was higher in women who recognized all harms and benefits (vs. not recognizing; OR, 2.47; 95% CI, 0.94-6.54). Sixty-six percent (65.8%) of tamoxifen users were unaware of its potential benefit and harms. Most (87.1%) women reported feeling informed about tamoxifen, and subjective decisional quality was high [Mean (SD), 17.03 (1.87), out of 18]. Knowledge regarding the potential harms and benefit of tamoxifen is low in women considering prevention therapy, and they may need additional support to make informed decisions about tamoxifen preventive therapy.

Abstract ES3-2: Sooner or later: considering risk over time, and implications for management

Abstract Cancer risk management revolves around the following important areas: genetic evaluation, surveillance recommendations, risk-reducing options, and lifestyle modification. Aspects of time are important for all of these areas, with the possible exception of lifestyle modification. For genetic evaluation, age at onset of affected individuals is a key parameter. Decisions about surveillance and risk-reducing strategies are based on age, and time-dependent estimates of cancer risk, with the most commonly-used time-frames being 5 years, 10 years, and remaining lifetime (to age 85 or 90). However, little attention is generally given to the time-frame of the benefit. For example, surveillance recommendations are based on lifetime risk when in fact the benefit (as defined by cancer detection success) cannot exceed the lead-time of the test. On the other hand, risk reduction (particularly with medication) is often presented based on risk estimated over the next 5 years. As more women are designated high risk, given increased prevalence of MRI surveillance and subsequent biopsies, and increased use of genetic testing with identification of moderate penetrance genetic variants, the question of risk thresholds that should be used for recommendations related to risk management become increasingly important. Surveillance recommendations: Remaining lifetime risk (RLR) estimates for women in their 40s generally project over 40 years or more. However, validation of these very long-term projections remains questionable, and validation is most robust for the 10-year time-frame (PMID 25956172). The lead-time gained with MRI surveillance has been estimated at 1-2 years for carriers of BRCA 1/2 mutations, and 4 years for non-carriers with positive family history of breast cancer (PMID 25820931) The predicted mean preclinical detectable phase (i.e. the time during which a cancer is screen-detectable) is estimated to be 1 to 4 years for BRCA1 and 2 to 7 years for BRCA2 (PMID 22744338). Similar estimates for non-carrier women at increased familial risk are unlikely to be longer than 10 years. Therefore, given the greater reliability of 10-year risk estimates, it appears most reasonable to make recommendations for intensified screening based on 10-year risk rather than RLR. Recommendations for use of risk-reducing medications (RR-meds): In contrast to screening, have been made to non-carrier high risk women based on 5-year risk estimates of 1.7% or greater. Acceptance of medications has been low for a variety of reasons, one of which is the seemingly small risk conveyed by a 5-year risk estimates. Here, it would seem reasonable to extend the time-frame over which risk is calculated, since the protective benefit of tamoxifen is known to extend to ~15 years, and is likely to be in the same range for aromatase inhibitors. New ASCO guidelines on use of RR-meds now includes 10-year estimates of 3% with the NCI BCRAT, or 5% with the Tyrer-Cuzick. In summary, the use of 10-year risk estimates would simplify the management counseling of women at increased risk of breast cancer for both practitioner and patient, and place it on a better evidence base than the use of RLR or the 5-year interval. Citation Format: SA Khan. Sooner or later: considering risk over time, and implications for management [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr ES3-2.

Abstract P2-11-03: Predictive significance of an optimized immunohistochemical panel for basal-like breast cancer on the CCTG MA.12 phase III randomized clinical trial

Abstract Background: Tamoxifen and aromatase inhibitors constitute the backbone of treatment for estrogen receptor positive early stage breast cancers based on immunohistochemical (IHC) results. While these therapies significantly reduce the risk of relapse of breast cancer, they have toxicities and add to costs. Gene expression profiling assays are widely used to quantify risk and support targeted therapies for luminal breast cancers treated with adjuvant endocrine therapy. In a prospective-retrospective analysis of the phase III CCTG MA.12 clinical trial (randomizing premenopausal women treated with adjuvant chemotherapy, to either tamoxifen or placebo for 5 years), luminal subtype by PAM50 was significantly predictive for tamoxifen benefit. However, IHC classification (as estrogen receptor positive) could not demonstrate a statistically significant benefit from tamoxifen over placebo. More accurate IHC biomarkers incorporating nestin positivity or loss of inositol polyphosphate-4-phosphate (INPP4B) have recently been optimized to identify the basal-like intrinsic subtype of breast cancer regardless of ER/PR/HER2 status. In this study, we examined the capacity of these basal biomarkers to identify intrinsic subtype and predict benefit from adjuvant tamoxifen vs. placebo in the CCTG MA.12 clinical trial Methods:492 formalin-fixed paraffin embedded blocks of primary tumor from patients randomized in the CCTG MA.12 trial were used to build tissue microarrays. IHC staining for nestin and INPP4B was done according to published methods, and interpretation was performed by pathologists with no access to molecular data. The performance of the nestin and INPP4B panel was assessed against PAM50 gene expression assay as a standard reference. A prespecified statistical plan was executed independently by the Canadian Cancer Trials Group, testing the primary hypothesis that patients with basal breast cancer, when defined as “positive for nestin or negative for INPP4B,” would not benefit from tamoxifen (primary endpoint: disease-free survival).Results: 366 primary tumor samples from the CCTG MA.12 had a full dataset available for IHCbiomarker evaluation, PAM50 subtype and clinical outcomes. Positive staining of nestin or loss of INPP4B was observed in 47 (13%) of the total cases and was significantly associated with poor prognostic factors including high grade, younger age, ER negativity, triple negative and core basal IHC status (p<0.01). “Nestin+ or INPP4B-” status was significantly associated with basal-like PAM50 gene expression subtype, while the other cases (nestin- and INPP4B+) were significantly associated with PAM50 luminal subtype. Patients assigned as basals by “nestin+ or INPP4B-” IHC status did not demonstrate a benefit from adjuvant tamoxifen vs. placebo (HR=1.39, 95%CI [0.37-5.26], p=0.63), whereas “nestin- and INPP4B+” cases displayed a significantly higher benefit from adjuvant tamoxifen vs. placebo (HR=0.67, 95% CI [0.45-0.98], p=0.04), (p-interaction=0.87). While, in this trial, ER clinical status as determined in community hospitals or centrally by single biomarker IHC was not significantly predictive for tamoxifen benefit, patients classified as IHC non-basal “nestin- and INPP4B+” within the ER+ subgroup did benefit from addition of tamoxifen (HR=0.62, 95%CI [0.38-1.01], p=0.05).Conclusions:The nestin/INPP4B IHC panel offers a feasible and inexpensive methodology to accurately identify intrinsic subtype of breast cancer. Patients assigned as IHC basal by this panel did not display a superior survival when treated with tamoxifen vs. placebo in the adjuvant setting. Within the ER+ subgroup, these cases could potentially be spared the side effects of currently recommended endocrine therapies that do not benefit this group of patients. Citation Format: Karama Asleh, Dongxia Gao, Vivien H Bramwell, Dongsheng Tu, Lois E Shepherd, Torsten O Nielsen. Predictive significance of an optimized immunohistochemical panel for basal-like breast cancer on the CCTG MA.12 phase III randomized clinical trial [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-11-03.

Increased Expression of Gankyrin and Stemness Factor Oct-4 are Associated with Unfavorable Clinical Outcomes and Poor Benefit of Tamoxifen in Breast Carcinoma Patients.

Tamoxifen is the most important treatment component in estrogen receptor positive (ER+) breast carcinoma patients. Tamoxifen resistance incidence presents an important obstacle in clinical treatment. Mechanisms underlying tamoxifen refractory are not completely understood. Although elevated expression of Gankyrin (P28GANK) and stem cell markers Nanog, Oct-4 and Sox-2 have been reported in breast carcinoma, their role in tamoxifen resistance progression has not been explored. In the present study, P28GANK and stem cell markers Nanog, Oct-4 and Sox-2 expression were evaluated using quantitative RT-PCR and immunohistochemical technology in 72 breast carcinoma patients who received tamoxifen as adjuvant anti-hormone treatment. Expression data were correlated with the clinical outcome and survival of patients. Data analysis showed that P28GANK, Oct-4 and Sox-2 transcripts were significantly overexpressed in tamoxifen resistance patients. Immunohistochemical staining indicated that protein expression of P28GANK and Oct-4 were also significantly higher in tamoxifen resistance patients. We have shown a positive correlation between mRNA and protein expression of P28GANK, Oct-4 and Sox-2. Multivariate logistic regression analysis indicated that P28GANK (P = 0.002) and Oct-4 (P = 0.013) overexpression could be negative independent factors of disease outcome. Additionally, in the whole study group, multivariate Cox regression analysis revealed that high expression of P28GANK and Oct-4 remained significant and unfavorable predictive factors for patients' survival. These findings suggest that Gankyrin and Oct-4 overexpression could promote tamoxifen refractory in breast cancer patients. More studies are warranted to clarify the predictive role of these potential biomarkers for patients who don't benefit from tamoxifen treatment and their possible application as prognostic markers in ER+ tamoxifen-treated breast carcinoma patients.

IGF-1R pathway activation as putative biomarker for linsitinib therapy to revert tamoxifen resistance in ER-positive breast cancer.

Preclinical studies indicate that activated IGF‐1R can drive endocrine resistance in ER‐positive (ER+) breast cancer, but its clinical relevance is unknown. We studied the effect of IGF‐1R signaling on tamoxifen benefit in patients and we searched for approaches to overcome IGF‐1R‐mediated tamoxifen failure in cell lines. Primary tumor blocks from postmenopausal ER+ breast cancer patients randomized between adjuvant tamoxifen versus nil were recollected. Immunohistochemistry for IGF‐1R, p‐IGF‐1R/InsR, p‐ERα(Ser118), p‐ERα(Ser167) and PI3K/MAPK pathway proteins was performed. Multivariate Cox models were employed to assess tamoxifen efficacy. The association between p‐IGF‐1R/InsR and PI3K/MAPK pathway activation in MCF‐7 and T47D cells was analyzed with Western blots. Cell proliferation experiments were performed under various growth‐stimulating and ‐inhibiting conditions. Patients with ER+, IGF‐1R‐positive breast cancer without p‐IGF‐1R/InsR staining (n = 242) had tamoxifen benefit (HR 0.41, p = 0.0038), while the results for p‐IGF‐1R/InsR‐positive patients (n = 125) were not significant (HR 0.95, p = 0.3). High p‐ERα(Ser118) or p‐ERα(Ser167) expression was associated with less tamoxifen benefit. In MCF‐7 cells, IGF‐1R stimulation increased phosphorylation of PI3K/MAPK proteins and ERα(Ser167) regardless of IGF‐1R overexpression. This could be abrogated by the dual IGF‐1R/InsR inhibitor linsitinib, but not by the IGF‐IR‐selective antibody 1H7. In MCF‐7 and T47D cells, stimulation of the IGF‐1R/InsR pathway resulted in cell proliferation regardless of tamoxifen. Abrogation of cell growth was regained by addition of linsitinib. In conclusion, p‐IGF‐1R/InsR positivity in ER+ breast cancer is associated with reduced benefit from adjuvant tamoxifen in postmenopausal patients. In cell lines, stimulation rather than overexpression of IGF‐1R is driving tamoxifen resistance to be abrogated by linsitinib.

Patient and provider factors associated with the noninitiation of tamoxifen for young women at high-risk for the development of breast cancer.

We sought to identify factors associated with disparities in tamoxifen utilization among young patients at high-risk for developing breast cancer. We identified 67 premenopausal, high-risk women age 35-45, without surgical prophylaxis, who did not initiate tamoxifen. Factors associated with noninitiation were examined. About 37% of patients had no documented provider-based discussion regarding initiation. Type of high-risk diagnosis was the only factor associated with a provider-based discussion (P=.03). For patients offered tamoxifen, primary reasons for noninitiation were perceived minimal benefit (66.7%), fertility concerns (16.7%), and concerns about side effects (7.1%). Implementation of comprehensive educational strategies regarding the benefits of tamoxifen should be facilitated to improve initiation among young high-risk patients.

Assessment of Long-term Distant Recurrence-Free Survival Associated With Tamoxifen Therapy in Postmenopausal Patients With Luminal A or Luminal B Breast Cancer

Patients with estrogen receptor (ER)-positive breast cancer have a long-term risk for fatal disease. However, the tumor biological factors that influence the long-term risk and the benefit associated with endocrine therapy are not well understood. To compare the long-term survival from tamoxifen therapy for patients with luminal A or luminal B tumor subtype. Secondary analysis of patients from the Stockholm Tamoxifen (STO-3) trial conducted from 1976 to 1990, which randomized postmenopausal patients with lymph node-negative breast cancer to receive adjuvant tamoxifen or no endocrine therapy. Tumor tissue sections were assessed in 2014 using immunohistochemistry and Agilent microarrays. Only patients with luminal A or B subtype tumors were evaluated. Complete long-term follow-up data up to the end of the STO-3 trial on December 31, 2012, were obtained from the Swedish National registers. Data analysis for the secondary analysis was conducted in 2017 and 2018. Patients were randomized to receive at least 2 years of tamoxifen therapy or no endocrine therapy; patients without recurrence who reconsented were further randomized to 3 additional years of tamoxifen therapy or no endocrine therapy. Distant recurrence-free interval (DRFI) by luminal A and luminal B subtype and trial arm was assessed by Kaplan-Meier analyses and time-dependent flexible parametric models to estimate time-varying hazard ratios (HRs) that were adjusted for patient and tumor characteristics. In the STO-3 treated trial arm, 183 patients had luminal A tumors and 64 patients had luminal B tumors. In the untreated arm, 153 patients had luminal A tumors and 62 had luminal B tumors. Age at diagnosis ranged from 45 to 73 years. A statistically significant difference in DRFI by trial arm was observed (log rank, P < .001 [luminal A subtype, n = 336], P = .04 [luminal B subtype, n = 126]): the 25-year DRFI for luminal A vs luminal B subtypes was 87% (95% CI, 82%-93%) vs 67% (95% CI, 56%-82%) for treated patients, and 70% (95% CI, 62%-79%) vs 54% (95% CI, 42%-70%) for untreated patients, respectively. Patients with luminal A tumors significantly benefited from tamoxifen therapy for 15 years after diagnosis (HR, 0.57; 95% CI, 0.35-0.94), and those with luminal B tumors benefited from tamoxifen therapy for 5 years (HR, 0.38; 95% CI, 0.24-0.59). Patients with luminal A subtype tumors had a long-term risk of distant metastatic disease, which was reduced by tamoxifen treatment, whereas patients with luminal B tumors had an early risk of distant metastatic disease, and tamoxifen benefit attenuated over time.

Tamoxifen therapy benefit predictive signature combining with prognostic signature in surgical-only ER-positive breast cancer.

Tamoxifen treatment is important assistant for estrogen-receptor-positive breast cancer (BRCA) after resection. This study aimed to identify signatures for predicting the prognosis of patients with BRCA after tamoxifen treatment. Data of gene-specific DNA methylation (DM), as well as the corresponding clinical data for the patients with BRCA, were obtained from The Cancer Genome Atlas and followed by systematic bioinformatics analyses. After mapping these DM CPG sites onto genes, we finally obtained 352 relapse-free survival (RFS) associated DM genes, with which 61,776 gene pairs were combined, including 1,614 gene pairs related to RFS. An 11 gene-pair signature was identified to cluster the 189 patients with BRCA into the surgical low-risk group (136 patients) and high-risk group (53 patients). Then, we further identified a tamoxifen-predictive signature that could classify surgical high-risk patients with significant differences on RFS. Combining surgical-only prognostic signature and tamoxifen-predictive signature, patients were clustered into surgical-only low-risk group, tamoxifen nonbenefit group, and tamoxifen benefit group. In conclusion, we identified that the gene pair PDHA2-APRT could serve as a potential prognostic biomarker for patients with BRCA after tamoxifen treatment.

G-protein-coupled estrogen receptor GPER-1 expression in hormone receptor-positive breast cancer is associated with poor benefit of tamoxifen.

The role of G-protein-coupled estrogen receptor 1 (GPER-1) in the development of tamoxifen resistance in breast cancer is a highly controversial issue. The aim of this study was to determine the expression of GPER-1 in the clinical routine under conditions of endocrine treatment. GPER-1 expression was analyzed in 442 patients with primary invasive breast cancer. GPER-1 score of > 3 was determined as positive. Expression data were correlated with clinical and pathological characteristics and patient survival. GPER-1 expression was observed in 352 (80.9%) cases, and positively correlated with estrogen and progesterone receptor status (p = 0.0001). GPER-1 positivity was associated with an increased grade of differentiation (p = 0.0001) and with a low level of Ki-67 expression (p = 0.0001). High GPER-1 expression was associated with a decreased level upon systemic treatment (p = 0.011). In the whole cohort, GPER-1 expression was associated with prolonged disease-free survival (DFS). DFS between tamoxifen- and aromatase inhibitor-treated GPER-1-positive patients was similar (p = 0.090). Notably, after matching the analysis for the most important prognostic factors, DFS for tamoxifen-treated GPER-1-positive patients was 69.1%, which is a percentage that is significantly lower compared to DFS for GPER-1-positive patients treated with aromatase inhibitors (92.7%) (p = 0.005). GPER-1 expression is a favorable prognostic factor in breast cancer patients. Its predictive role for poor benefit form tamoxifen treatment should be investigated in further studies.

Hierarchical clustering of activated proteins in the PI3K and MAPK pathways in ER-positive, HER2-negative breast cancer with potential therapeutic consequences

BackgroundThe phosphatidylinositol-3-kinase (PI3K) and/or mitogen-activated protein kinase (MAPK) pathways are frequently activated in breast cancer which can result in antioestrogen resistance. Single protein markers failed to be introduced into clinical practice. We, therefore, aimed to find a better read-out of activation of the PI3K and MAPK pathways in ER+/HER2− breast cancer. Assessment of seven PI3K/MAPK proteins might better reflect pathway activation and distinguish patients without adjuvant tamoxifen benefit.MethodsTumour blocks were recollected from 293 primary postmenopausal ER+/HER2− breast cancer patients randomised between tamoxifen and no adjuvant therapy. PTEN, p-AKT(Thr308), p-AKT(Ser473), p-p70S6K, p-4EBP1, p-ERK1/2 and p-S6RP expression was assessed by immunohistochemistry followed by unsupervised hierarchical clustering. The primary endpoint was recurrence-free interval. Multivariate Cox models were used to assess tamoxifen benefit. A classification tool was developed based on protein expression profile.ResultsSubgroups were identified with preferentially activated (A) and preferentially not activated (N) proteins. Patients in group N derived significant benefit from tamoxifen (multivariate hazard ratio (HR) = 0.23, p = 0.000101), while patients from group A did not (multivariate HR = 1.37, p = 0.64), p for interaction 0.020. Our generated classification tool confirmed these results (p for interaction 0.024).ConclusionsHierarchical clustering of seven PI3K/MAPK proteins reflects pathway activation and can guide treatment decisions in primary ER+/HER2− postmenopausal breast cancer patients.

Mitotic count can predict tamoxifen benefit in postmenopausal breast cancer patients while Ki67 score cannot

BackgroundControversy exists for the use of Ki67 protein expression as a predictive marker to select patients who do or do not derive benefit from adjuvant endocrine therapy. Whether other proliferation markers, like Cyclin D1, and mitotic count can also be used to identify those estrogen receptor α (ERα) positive breast cancer patients that derive benefit from tamoxifen is not well established. We tested the predictive value of these markers for tamoxifen benefit in ERα positive postmenopausal breast cancer patients.MethodsWe collected primary tumor blocks from 563 ERα positive patients who had been randomized between tamoxifen (1 to 3 years) vs. no adjuvant therapy (IKA trial) with a median follow-up of 7.8 years. Mitotic count, Ki67 and Cyclin D1 protein expression were centrally assessed by immunohistochemistry on tissue microarrays. In addition, we tested the predictive value of CCND1 gene copy number variation using MLPA technology. Multivariate Cox proportional hazard models including interaction between marker and treatment were used to test the predictive value of these markers.ResultsPatients with high Ki67 (≥5%) as well as low (< 5%) expressing tumors equally benefitted from adjuvant tamoxifen (adjusted hazard ratio (HR) 0.5 for both groups)(p for interaction 0.97). We did not observe a significant interaction between either Cyclin D1 or Ki67 and tamoxifen, indicating that the relative benefit from tamoxifen was not dependent on the level of these markers. Patients with tumors with low mitotic count derived substantial benefit from tamoxifen (adjusted HR 0.24, p < 0.0001), while patients with tumors with high mitotic count derived no significant benefit (adjusted HR 0.64, p = 0.14) (p for interaction 0.03).ConclusionPostmenopausal breast cancer patients with high Ki67 counts do significantly benefit from adjuvant tamoxifen, while those with high mitotic count do not. Mitotic count is a better selection marker for reduced tamoxifen benefit than Ki67.

Uptake of breast cancer preventive therapy in the UK: results from a multicentre prospective survey and qualitative interviews

PurposeUptake of preventive therapy for women at increased breast cancer risk in England is unknown following the introduction of UK clinical guidelines in 2013. Preventive therapy could create socioeconomic inequalities in cancer incidence if it is more readily accepted by particular socio-demographic groups. In this multicentre study, we investigated uptake of tamoxifen and evaluated socio-demographic and clinical factors associated with initiation. We explored women’s experiences of treatment decision-making using qualitative interview data.MethodsBetween September 2015 and December 2016, women (n = 732) attending an appointment at one of 20 centres in England to discuss breast cancer risk were approached to complete a survey containing socio-demographic details and nulliparity. Of the baseline survey respondents (n = 408/732, 55.7% response rate), self-reported uptake of tamoxifen at 3-month follow-up was reported in 258 (63.2%). Sixteen women participated in semi-structured interviews.ResultsOne in seven (38/258 = 14.7%) women initiated tamoxifen. Women who had children were more likely to report use of tamoxifen than those without children (OR = 5.26; 95%CI: 1.13–24.49, p = 0.035). Interview data suggested that women weigh up risks and benefits of tamoxifen within the context of familial commitments, with exposure to significant other’s beliefs and experiences of cancer and medication a basis for their decision.ConclusionsUptake of tamoxifen is low in clinical practice. There were no socio-demographic differences in uptake, suggesting that the introduction of breast cancer preventive therapy is unlikely to create socioeconomic inequalities in cancer incidence. Women’s decision-making was influenced by familial priorities, particularly having children.

Abstract PD4-12: Clustering of activated proteins of the PI3K and MAPK pathways distinguishes ER+/HER2- primary breast cancer patients with preferential tamoxifen benefit

Abstract Background Several (activated) proteins of the phosphatidylinositol-3-kinase (PI3K) and/or mitogen-activated protein kinase (MAPK) pathway have been analyzed for an association with adjuvant tamoxifen benefit in estrogen receptor-positive (ER+), HER2-negative (HER2-) breast cancer. Currently, no single protein has yielded convincing results allowing clinical implementation. Combining activated proteins could provide more robust predictive potential. We used unsupervised hierarchical clustering of 7 activated proteins downstream in these pathways, discriminated by expression profile, to analyze adjuvant tamoxifen benefit in ER+/HER2- postmenopausal breast cancer patients. Further, we developed a classification tool based on the generated heatmap groups by pathway activation status to categorize future patients into sensitive for or resistant to adjuvant tamoxifen. Methods Primary tumor blocks from 489 ER+/HER2- (stage I-III) postmenopausal patients previously randomized between tamoxifen (1 to 3 years) vs no adjuvant therapy (IKA trial 1982-1993; Beelen et al, Breast Cancer Res, 2014) were used for immunohistochemistry on tissue microarrays. Median follow-up of the patients without a recurrence event was 8.5 years. Scoring of PTEN, p-AKT(Thr308), p-AKT(Ser473) and p-p70S6K(Thr389) was by cytoplasmic intensity (0-3), p-4EBP1(Ser65) and pERK1/2(Thr202/204) by percentage of tumor cells with positive nuclear staining and p-S6RP(Ser235/236) by the percentage of tumor cells with positive membranous staining. Unsupervised hierarchical clustering was performed on tissue from 293 patients with informative data on all 7 proteins. Cox models were used to assess tamoxifen benefit (defined as the Hazard ratio (HR) of tamoxifen treatment vs no adjuvant therapy for recurrence-free interval) and to compare this benefit between subgroups generated by clustering as well as generated by the classification tool. Cox models included covariates (age, histological grade and subtype, tumor size, PR status) and were stratified for lymph node status. Results Two distinct groups were identified based on hierarchical clustering: one with preferentially activated pathway markers (A) and one with relatively no activation (N). Patients in group N derived significant benefit from tamoxifen (multivariable HR 0.28, 95% CI 0.14 − 0.56, p = 0.000324), while patients from group A had no benefit (multivariable HR 1.57, 95% CI 0.44 – 5.56, p = 0.482), p for interaction 0.018. Contradictory, patients in group A had a better prognosis compared to those in group N (multivariable HR 0.17, 95% CI 0.04 − 0.7, p = 0.014). The classification tool was also successful in differentiating ER+/HER2- patients with or without tamoxifen benefit (p for interaction = 0.016). Conclusions Hierarchical clustering of PI3K/MAPK pathway proteins is able to differentiate patients with adjuvant tamoxifen benefit and patients who would potentially need alternative treatment, for instance with inhibitors of the PI3K or MAPK pathway. The classification tool distinguishing patients with and without tamoxifen benefit should be validated in an independent cohort of postmenopausal patients with primary ER+/HER2- breast cancer. Citation Format: Kruger DT, Beelen K, Opdam M, Sanders J, van der Noort V, Boven E, Linn SC. Clustering of activated proteins of the PI3K and MAPK pathways distinguishes ER+/HER2- primary breast cancer patients with preferential tamoxifen benefit [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD4-12.