Concordance between results of inexpensive statistical models and multigene signatures in patients with ER+/HER2- early breast cancer.

Multigene signatures (MGS) are used to guide adjuvant chemotherapy (aCT) decisions in patients diagnosed with estrogen receptor (ER)-positive HER2-negative early breast cancer. We used results from three MGS (Oncotype DX® (ODX), MammaPrint® (MP) or Prosigna®) and assessed the concordance between high or low risk of recurrence and the predicted risk of recurrence based on statistical models. In addition, we looked at the impact of MGS results on final aCT administration during the multidisciplinary meeting (MDM). We retrospectively included 129 patients with ER-positive HER2-negative early breast cancer for which MGS testing was performed after MDM at University Hospitals Leuven between May 2013 and April 2019 in case there was doubt about aCT recommendation. Tumor tissue was analyzed either by ODX (N = 44), MP (N = 28), or Prosigna® (N = 57). Eight statistical models were computed: Magee equations (ME), Memorial Sloan Kettering simplified risk score (MSK-SRS), Breast Cancer Recurrence Score Estimator (BCRSE), OncotypeDXCalculator (ODXC), new Adjuvant! Online (nAOL), Mymammaprint.com (MyMP), PREDICT, and SiNK. Concordance, negative percent agreement, and positive percent agreement were calculated. Of 129 cases, 53% were MGS low and 47% MGS high risk. Concordances of 100.0% were observed between risk results obtained by ODX and ME. For MP, BCRSE demonstrated the best concordance, and for Prosigna® the average of ME. Concordances of <50.0% were observed between risk results obtained by ODX and nAOL, ODX and MyMP, ODX and SiNK, MP and MSK-SRS, MP and nAOL, MP and MyMP, MP and SiNK, and Prosigna® and ODXC. Integration of MGS results during MDM resulted in change of aCT recommendation in 47% of patients and a 15% relative and 9% absolute reduction. In conclusion, statistical models, especially ME and BCRSE, can be useful in selecting ER-positive HER2-negative early breast cancer patients who may need MGS testing resulting in enhanced cost-effectiveness and reduced delay in therapeutic decision-making.

Prognostic Value of the Progesterone Receptor by Subtype in Patients with Estrogen Receptor-Positive, HER-2 Negative Breast Cancer.

BACKGROUND: In estrogen receptor-positive (ER+), human epidermal growth factor receptor 2 (HER-2) negative breast cancers, the progesterone receptor (PR) is an independent prognostic marker. Little is known about the prognostic value of PR by tumor grade. We assessed this in two independent datasets. PATIENTS AND METHODS: Women with primary operable, invasive ER+ HER-2 negative breast cancer diagnosed between 2000 and 2012, treated at University Hospitals Leuven, were included. We assessed the association of PR status and subtype (grade 1-2 vs. grade 3) with distant recurrence-free interval (DRFI) and breast cancer-specific survival. The interaction between PR status and subtype was investigated, and associations of PR status by subtype were calculated. The BIG 1-98 data set was used for validation. RESULTS: In total, 4,228 patients from Leuven and 5,419 from BIG 1-98 were analyzed. In the Leuven cohort, the adjusted hazard ratio (HR) of PR-positive versus PR-negative tumors for DRFI was 0.66 (95% confidence interval [CI], 0.50-0.89). For the interaction with subtype (p = .34), the HR of PR status was 0.79 (95% CI, 0.61-1.01) in luminal A-like and 0.59 (95% CI, 0.46-0.76) in luminal B-like tumors. In luminal A-like tumors, observed 5-year cumulative incidences of distant recurrence were 4.1% for PR-negative and 2.8% for PR-positive tumors, and in luminal B-like 18.7% and 9.2%, respectively. In the BIG 1-98 cohort, similar results were observed; for the interaction with subtype (p = .12), the adjusted HR of PR status for DRFI was 0.88 (95% CI, 0.57-1.35) in luminal A-like and 0.58 (95% CI, 0.43-0.77) in luminal B-like tumors. Observed 5-year cumulative incidences were similar. CONCLUSION: PR positivity may be more protective against metastatic relapse in luminal B-like versus luminal A-like breast cancer, but no strong conclusions can be made. In absolute risk, results suggest an absent PR is clinically more important in high compared with low proliferative ER+ HER-2 negative tumors. IMPLICATIONS FOR PRACTICE: An absent progesterone receptor (PR) predicts a worse outcome in women treated for an estrogen receptor-positive, human epidermal growth factor receptor 2 negative breast cancer. As low proliferative tumors lacking PR are now also classified high risk, the prognostic value of PR across risk groups was studied. Despite a negative test for interaction of the prognostic value of PR by tumor grade, the magnitude of an absent PR on breast cancer relapse is much larger in high than in low proliferative breast cancers.

Identification, clinical-pathological characteristics and treatment outcomes of patients with metastatic breast cancer and somatic human epidermal growth factor receptor 2 (ERBB2) mutations.

PURPOSE: The human epidermal growth factor receptor 2 (ERBB2) may harbour somatic mutations that drive breast tumorigenesis. Here, we study prevalence, tumour characteristics and disease outcome of ERBB2 mutations in a large unselected cohort of metastatic breast cancer (mBC) patients. METHODS: We retrospectively included all mBC patients with sufficient primary breast tumour, diagnosed between 2000 and 2015 (n = 775). Genomic DNA was subjected to a targeted-resequencing assay to identify hotspot mutations in exon 8, 17, 19, 20, and 21 of ERBB2. We studied demographics, tumour characteristics, median distant disease-free survival (DDFS), using a time-to-event analysis and time to progression (TTP) and overall survival (OS) upon metastasis, using Kaplan-Meier and log-rank statistics to assess differences between ERBB2-mutation statuses. RESULTS: ERBB2 mutations were observed in 1.8% of the samples (13/721). Patient and tumour characteristics were independent of ERBB2 mutations. Luminal ERBB2-mutated (ERBB2mut+) cases (n = 5) had a shorter DDFS than ERBB2mut- cases (median DDFS 0.8 vs. > 4.0 years, p = 0.02). ER-positive ERBB2mut+ patients who received an aromatase inhibitor (AI) as first-line treatment (stage IV disease) had a worse TTP vs. ERBB2mut- patients (n = 3 vs. 156; median TTP 103 vs. 311 days, p = 0.04). OS for all subtypes was lower for ERBB2mut+ vs. ERBB2mut- cases (n = 11 vs. 669; median OS 1.1 vs. 2.3 years, p = 0.46). CONCLUSION: ERBB2mut+ are rare in patients in whom mBC developed and no evidence was found for an association with specific types of BC or patient characteristics, although outcomes of ERBB2mut+ carriers might be worse. The latter, however, needs to be validated in larger populations.

Tumor characteristics and outcome by androgen receptor expression in triple-negative breast cancer patients treated with neo-adjuvant chemotherapy.

PURPOSE: To assess clinical pathological characteristics and outcome of triple-negative breast cancers (TNBC) by androgen receptor (AR) protein expression. METHODS: We retrospectively evaluated AR by immunohistochemistry on core-needle biopsy, (CNB) and residual disease (RD) in a consecutive institutional series of TNBC patients treated with neo-adjuvant chemotherapy (NACT) between 2000 and 2017. We investigated univariate associations between AR-expression on CNB (using different cut-offs), clinical pathological variables, and pathologic complete response (pCR). Next, we used multiple correspondence analysis (MCA) to investigate the relationships between AR on CNB and standard clinical and pathological variables, including stromal tumor infiltrating lymphocytes (sTILs). Finally, we investigated the prognostic value of AR-expression on CNB and RD using the Fine and Gray model. RESULTS: We included 71 patients; median follow-up was 6.7 years. Considering the ≥ 1% cut-off, AR was present in 32% on the CNB and 14% on RD. AR-low (1-34% positive tumor cells) patients were associated with younger (premenopausal) age and AR-high (≥ 34% positive tumor cells) with older (postmenopausal) age. AR on CNB did not correlate with other features nor was it predictive for pCR or prognostic for metastatic outcome, regardless of the used cut-off. The MCA suggested that body mass index (BMI) affects the predictive role of AR-low and -high for pCR differently. AR-loss on RD was prognostic for a better 5-year distant disease-free survival (DDFS) as compared to RD with retained AR-expression (61.6% (95% CI 44.26-79.14) and 25.0% (95% CI 3.94-87.21), respectively; p = 0.01). CONCLUSION: Low and high AR-expression on CNB of TNBC were correlated with age and menopausal status but qualitative AR was not predictive for pCR. AR-loss on RD was prognostic for DDFS in TNBC patients treated with NACT.

Gene-environment interactions involving functional variants: Results from the Breast Cancer Association Consortium.

Investigating the most likely causal variants identified by fine-mapping analyses may improve the power to detect gene-environment interactions. We assessed the interplay between 70 single nucleotide polymorphisms identified by genetic fine-scale mapping of susceptibility loci and 11 epidemiological breast cancer risk factors in relation to breast cancer. Analyses were conducted on up to 58,573 subjects (26,968 cases and 31,605 controls) from the Breast Cancer Association Consortium, in one of the largest studies of its kind. Analyses were carried out separately for estrogen receptor (ER) positive (ER+) and ER negative (ER-) disease. The Bayesian False Discovery Probability (BFDP) was computed to assess the noteworthiness of the results. Four potential gene-environment interactions were identified as noteworthy (BFDP < 0.80) when assuming a true prior interaction probability of 0.01. The strongest interaction result in relation to overall breast cancer risk was found between CFLAR-rs7558475 and current smoking (ORint = 0.77, 95% CI: 0.67-0.88, pint = 1.8 × 10-4 ). The interaction with the strongest statistical evidence was found between 5q14-rs7707921 and alcohol consumption (ORint =1.36, 95% CI: 1.16-1.59, pint = 1.9 × 10-5 ) in relation to ER- disease risk. The remaining two gene-environment interactions were also identified in relation to ER- breast cancer risk and were found between 3p21-rs6796502 and age at menarche (ORint = 1.26, 95% CI: 1.12-1.43, pint =1.8 × 10-4 ) and between 8q23-rs13267382 and age at first full-term pregnancy (ORint = 0.89, 95% CI: 0.83-0.95, pint = 5.2 × 10-4 ). While these results do not suggest any strong gene-environment interactions, our results may still be useful to inform experimental studies. These may in turn, shed light on the potential interactions observed.

The prognostic performance of Adjuvant! Online and Nottingham Prognostic Index in young breast cancer patients.

BACKGROUND: Limited data are available on the prognostic performance of Adjuvant! Online (AOL) and Nottingham Prognostic Index (NPI) in young breast cancer patients. METHODS: This multicentre hospital-based retrospective cohort study included young (⩽40 years) and older (55-60 years) breast cancer patients treated from January 2000 to December 2004 at four large Belgian and Italian institutions. Predicted 10-year overall survival (OS) and disease-free survival (DFS) using AOL and 10-year OS using NPI were calculated for every patient. Tools ability to predict outcomes (i.e., calibration) and their discriminatory accuracy was assessed. RESULTS: The study included 1283 patients, 376 young and 907 older women. Adjuvant! Online accurately predicted 10-year OS (absolute difference: 0.7%; P=0.37) in young cohort, but overestimated 10-year DFS by 7.7% (P=0.003). In older cohort, AOL significantly underestimated both 10-year OS and DFS by 7.2% (P<0.001) and 3.2% (P=0.04), respectively. Nottingham Prognostic Index significantly underestimated 10-year OS in both young (8.5%; P<0.001) and older (4.0%; P<0.001) cohorts. Adjuvant! Online and NPI had comparable discriminatory accuracy. CONCLUSIONS: In young breast cancer patients, AOL is a reliable tool in predicting OS at 10 years but not DFS, whereas the performance of NPI is sub-optimal.

Androgen deprivation by adrenal suppression using low-dose hydrocortisone for the treatment of breast carcinoma with apocrine features: a case report illustrating this new paradigm.

We report on a postmenopausal patient with a secondary metastatic apocrine breast cancer successfully treated with low-dose hydrocortisone only following several lines of chemotherapy. The tumor cells in the primary and metastatic lesion exhibited a 'triple-negative' status (estrogen receptor (ER)-, progesterone receptor (PR)-, and human epidermal growth factor receptor 2 (HER2)-negative); the androgen receptor (AR) was strongly expressed. Twenty milligrams of hydrocortisone, a low substitution dose known to suppress adrenal steroid production, twice daily led to a clinical benefit lasting for one year, with symptom control, radiologically stable disease, and steady decrease in CA15.3. Our observation demonstrates that an AR-expressing apocrine breast cancer may respond to androgen deprivation, as an ER-positive breast cancer may benefit from estrogen deprivation. It highlights the importance of further research targeting the AR pathway in apocrine carcinoma, for which androgens represent the sole (known) steroid hormone stimulating tumor growth. Future clinical trials should not only focus on AR inhibitors like enzalutamide, but also on ablative modalities like low-dose hydrocortisone aiming at medical adrenalectomy. This method of androgen deprivation is largely available, cheap, and nearly devoid of toxicity.

The UZ Leuven Policy for Extended Adjuvant Anti-estrogen Therapy in Women With Early Estrogen Receptor-Positive Breast Cancer.

Opinion statement: Five years after adjuvant endocrine treatment for estrogen receptor (ER)-positive breast cancer, patients have a 2 to 20 % risk of metastatic relapse during the next 5 years. Extended adjuvant endocrine therapy seems to further lower this. In UZ Leuven, extended endocrine therapy is now discussed unless the tumor was a grade 1-2, pT1N0, ER-positive, progesterone receptor (PR)-positive, HER2-negative lesion. After 5 years of adjuvant tamoxifen treatment for ER-positive breast cancer, we encourage women to take another 5 years of tamoxifen. If the tumor was lymph node-positive at diagnosis and patients are menopausal after the first 5 years of tamoxifen, we advise to take prolonged treatment with an oral aromatase inhibitor (AI). For this particular group, available data for extending endocrine therapy with an AI after 5 years of tamoxifen are strongest and more convincing for letrozole than for anastrozole or exemestane. Under these conditions, letrozole is reimbursed for 3 years in Belgium. If women are postmenopausal at diagnosis and already used an oral AI at any time during the first 5 years, we discuss an extra 5 years of tamoxifen. Results from ongoing clinical trials will tell us whether in these cases prolonged AI use is better than tamoxifen so that therapy can be adapted. Benefit from extended adjuvant endocrine therapy is likely larger with better compliance and potential side effects of extended endocrine therapy need to be discussed. Therefore, when advising extended adjuvant endocrine treatment, a balance should always be made between relapse risk and treatment tolerance/compliance.

Body Mass Index and Tumor-Infiltrating Lymphocytes in Triple-Negative Breast Cancer.

BACKGROUND: High levels of stromal tumor-infiltrating lymphocytes (sTIL) are associated with increased pathological complete response (pCR) rate and longer survival after neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) patients. Here, we evaluated the value of sTIL in predicting pCR and explored prognosis in TNBC patients treated with neoadjuvant chemotherapy according to body mass index (BMI). METHODS: sTIL were scored centrally on pretreatment biopsies from 2 retrospective series of nonunderweight TNBC patients (n = 445). sTIL and BMI were considered as binary (sTIL: <30.0% vs ≥30.0%; BMI: lean vs overweight and obese) and continuous variables. Associations with pCR (ypT0/isN0) were assessed using logistic regression, and associations with event-free survival and overall survival were assessed using Cox regressions. RESULTS: 236 (53.0%) patients were lean and 209 (47.0%) overweight and obese. pCR was achieved in 181 of 445 (41.7%) patients. Median sTIL was 11.0%, and 99 of 445 (22.2%) tumors had high sTIL. A statistically significant interaction between sTIL and BMI, considered as categorical or continuous variables, for predicting pCR was observed in the multivariable analysis (Pinteraction = .03 and .04, respectively). High sTIL were statistically significantly associated with pCR in lean (odds ratio [OR] = 4.24, 95% confidence interval [CI] = 2.10 to 8.56; P < .001) but not in heavier patients (OR = 1.48, 95% CI = 0.75 to 2.91; P = .26) in the multivariable analysis. High sTIL were further associated with increased event-free survival in lean (hazard ratio [HR] = 0.22, 95% CI = 0.08 to 0.62; P = .004) but not in heavier patients (HR = 0.53, 95% CI = 0.26 to 1.08; P = .08). Similar results were obtained for overall survival. CONCLUSION: BMI is modifying the effect of sTIL on pCR and prognosis in TNBC patients treated with neoadjuvant chemotherapy.

Correction to: Unexpected Benefit from Alpelisib and Fulvestrant in a Woman with Highly Pre-treated ER-Positive, HER2-Negative PIK3CA Mutant Metastatic Breast Cancer.

Dr. Arteaga serves on an Advisory Board for Novartis and was a consultant for AstraZeneca from 2015 to 2016. All other authors declare that they have no competing interests.

Tamoxifen Pharmacogenetics and Metabolism: Results From the Prospective CYPTAM Study.

PURPOSE: Tamoxifen is widely prescribed as adjuvant therapy in patients with early-stage breast cancer. It has been postulated that concentrations of endoxifen, the active metabolite of tamoxifen, are a better predictor of tamoxifen efficacy than CYP2D6 genotypes. Although in a retrospective study, an endoxifen threshold of 5.9 ng/mL for efficacy was described, confirmation based on prospective studies is lacking. The objective of the prospective CYPTAM (The Netherlands National Trial Register: NTR1509) study was to associate endoxifen concentrations and CYP2D6 genotypes with clinical outcome in patients with early-stage breast cancer receiving tamoxifen. PATIENTS AND METHODS: From February 2008 to December 2010, patients with breast cancer treated with adjuvant tamoxifen were included. Patients could be enrolled up to a maximum of 12 months after tamoxifen initiation. Blood samples were retrieved for CYP2D6 genotyping and endoxifen measurements by Amplichip (Roche Diagnostics, Indianapolis, IN) and high-performance liquid chromatography-tandem mass spectrometry, respectively. Endoxifen concentrations were analyzed as a continuous variable, classifying patients into quartiles and using an endoxifen threshold of 5.9 ng/mL. Endoxifen concentrations and CYP2D6 genotypes were associated with relapse-free survival (censored at the time of tamoxifen discontinuation; RFSt) by Cox regression analysis. RESULTS: A total of 667 pre- and postmenopausal patients were enrolled and had received tamoxifen for a median time of 0.37 years (range, 0.23 to 0.6 years) before study entry. No association was found between endoxifen concentrations and RFSt (adjusted hazard ratio, 0.991; 95% CI, 0.946 to 1.038; P = .691). Also, neither categorizing endoxifen concentrations into quartiles nor using 5.9 ng/mL as threshold altered these results. In addition, no association was found between CYP2D6 genotype and RFSt (adjusted hazard ratio, 0.929; 95% CI, 0.525 to 1.642; P = .799). CONCLUSION: This prospective clinical study shows no association between endoxifen concentrations or CYP2D6 genotypes and clinical outcome in patients with early-stage breast cancer receiving adjuvant tamoxifen.

Decentralization of Next-Generation RNA Sequencing-Based MammaPrint® and BluePrint® Kit at University Hospitals Leuven and Curie Institute Paris.

A previously developed and centrally validated MammaPrint® (MP) and BluePrint® (BP) targeted RNA next-generation sequencing (NGS) kit was implemented and validated in two large academic European hospitals. Additionally, breast cancer molecular subtypes by MP and BP RNA sequencing were compared with immunohistochemistry (IHC). Patients with early breast cancer diagnosed at University Hospitals Leuven and Curie Institute Paris were prospectively included between September 2017 and January 2018. Formalin-fixed paraffin-embedded tissue sections were analyzed with MP and BP NGS technology at the beta sites and with both NGS and microarray technology at Agendia. Raw NGS data generated on Illumina MiSeq instruments at the beta sites were interpreted and compared with NGS and microarray data at Agendia. MP and BP NGS molecular subtypes were compared to surrogate IHC breast cancer subtypes. Equivalence of MP and BP indices was determined by Pearson's correlation coefficient. Acceptable limits were defined a priori, based on microarray data generated at Agendia between 2012 and 2016. The concordance, the Negative Percent Agreement and the Positive Percent Agreement were calculated based on the contingency tables and had to be equal to or higher than 90%. Out of 124 included samples, 48% were MP Low and 52% High Risk with microarray. Molecular subtypes were BP luminal, HER2 or basal in 82%, 8% and 10% respectively. Concordance between MP microarray at Agendia and MP NGS at the beta sites was 91.1%. Concordance of MP High and Low Risk classification between NGS at the beta sites and NGS at Agendia was 93.9%. Concordance of MP and BP molecular subtyping using NGS at the beta sites and microarray at Agendia was 89.5%. Concordance between MP and BP NGS subtyping, and IHC was 71.8% and 76.6%, for two IHC surrogate models. The MP/BP NGS kit was successfully validated in a decentralized setting.

Unexpected Benefit from Alpelisib and Fulvestrant in a Woman with Highly Pre-treated ER-Positive, HER2-Negative PIK3CA Mutant Metastatic Breast Cancer.

We present the case of a postmenopausal patient with a secondary metastatic ER-positive, HER2-negative breast cancer who was successfully treated with fulvestrant and alpelisib following six lines of therapy. The tumour showed two uncommon PIK3CA mutations, and with the combination of alpelisib and fulvestrant the patient went from ECOG grade 3, before the start of this therapy, to ECOG grade 1 during treatment until progressive disease after 6 months. This unexpected benefit emphasizes the importance of performing a Next Generation Sequencing (NGS)-based assay to screen for several cancer genes in the metastatic setting, even after more than four lines of therapy and a high ECOG grade. Moreover, the use of alpelisib may be beneficial for uncommon PIK3CA mutations.

Tamoxifen Metabolism and Efficacy in Breast Cancer: A Prospective Multicenter Trial.

Purpose: Levels of endoxifen, the most active metabolite of tamoxifen, vary by the highly polymorphic cytochrome P450 (CYP) 2D6 enzyme. We prospectively investigated tamoxifen efficacy by serum endoxifen levels and the tamoxifen activity score (TAS).Experimental Design: A prospective observational multicenter study included postmenopausal women with an estrogen receptor-positive breast cancer receiving first-line tamoxifen, 20 mg daily in the neoadjuvant or metastatic setting, recruited between February 2009 and May 2014. The primary endpoint was the objective response rate (ORR) using RECIST criteria 1.0. Secondary endpoints were clinical benefit (CB), progression-free survival (PFS), and tolerability of tamoxifen. The main analysis used logistic regression to relate ORR to serum endoxifen levels after 3 months. Endpoints were also related to other tamoxifen metabolites and to TAS.Results: Endoxifen levels were available for 247 of all 297 patients (83%), of which 209 with target lesions (85%). Median follow-up time for PFS was 32.5 months, and 62% progressed. ORR and CB were 45% and 84%, respectively. ORR was not related to endoxifen, and the OR of ORR was 1.008 per µg/L increase in endoxifen (95% confidence interval, 0.971-1.046; P = 0.56). In general, none of the endpoints was associated with endoxifen levels, tamoxifen metabolites, or TAS.Conclusions: Under the prespecified assumptions, the results from this prospective clinical trial do not suggest therapeutic drug monitoring of endoxifen to be of clinical value in postmenopausal women treated with tamoxifen for breast cancer in the neoadjuvant or metastatic setting. Clin Cancer Res; 24(10); 2312-8. ©2018 AACR.