The Changing Role of Gene-Expression Profiling in the Era of De-escalating Adjuvant Chemotherapy in Early-Stage Breast Cancer

Purpose

We assessed the recent trends in the administration of adjuvant chemotherapy thereby evaluating the role of the 70-gene signature (70-GS) testing in decision-making in the systemic treatment of patients with lymph node negative (N0) and lymph node positive (N+) breast cancer.

Methods

Patients with a national guideline directed indication for 70-GS use treated between 2013 and 2016 were selected from the Netherlands Cancer Registry. Time trends in the administration of adjuvant chemotherapy were evaluated within guideline- and age-delineated subgroups. The influence of the 70-GS on chemotherapy use was assessed with logistic regression.

Results

During the study period, the overall administration of adjuvant chemotherapy decreased from 49 to 23% and 70-GS use increased from 24 to 51%. The 70-GS was not associated with a decreased likelihood for N0 patients to receive chemotherapy (odds ratio [OR] 1.0; 95% confidence interval [CI] 0.86–1.17), as the proportion of N0 patients who received chemotherapy in the absence of 70-GS use decreased during the study period. In patients with N1a disease, 70-GS testing was associated with a decreased likelihood to receive chemotherapy (OR 0.21; 95% CI 0.15–0.29). In patients < 50 years and 50–59 years of age, 70-GS use was associated with a consistent lower proportion of patients receiving chemotherapy throughout the study period (OR 0.17; 95% CI 0.13–0.23 and OR 0.53; 95% CI 0.43–0.65, respectively).

Conclusions

In this population-based study, the administration of adjuvant chemotherapy in ER+ breast cancer strongly declined. For node-positive and younger patients, 70-GS use was associated with a decreased probability for patients to receive adjuvant chemotherapy.

Electronic supplementary material

The online version of this article (10.1245/s10434-019-07511-8) contains supplementary material, which is available to authorized users.

Abstract P3-08-09: Impact of gene-expression profiling in patients with early breast cancer when applied outside the guideline directed indication area

Purpose

In Dutch guidelines gene expression profiles (GEP) are indicated in estrogen receptor positive early breast cancer patients in whom benefit of chemotherapy (CT) is controversial based on traditional prognostic factors alone. Aim of the current study is to assess the use and impact of GEP on administration of adjuvant CT in breast cancer patients who have according to national guidelines a clear indication to either use or withhold adjuvant chemotherapy (clinical high or low risk).

Methods

Clinical low- and high risk patients, according to Dutch breast cancer guidelines, diagnosed between 2011-2014 were selected from the Netherlands Cancer Registry (NCR). Influence of GEP use and GEP test result on CT administration was assessed with logistic regression.

Results

Overall, 26,425 patients were identified; 4.8% of patients with clinical low- risk (444/ 9,354), 7.5% of the patients with a clinical high-risk (1,281/ 17,071) received a GEP. GEP use was associated with a significantly increased odds of CT administration in clinical low-risk patients (OR=2.12 95%CI: 1.44-3.11). In clinical high-risk patients GEP use was associated with a decreased frequency of CT administration (OR=0.55, 95%CI: 0.48-0.63). Adherence to the GEP result was higher in clinical high-risk patients with a discordant GEP result as compared to clinical low-risk patients with a discordant GEP result: 71.7% vs. 52.2%, respectively.

Conclusion

GEP is frequently used outside the indicated area and significantly influenced the administration of adjuvant CT, although adherence to the test-result was limited.

Citation Format: Schreuder K, Kuijer A, Rutgers EJTh, Smorenburg CH, Van Dalen T, Siesling S. Impact of gene-expression profiling in patients with early breast cancer when applied outside the guideline directed indication area [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 P3-08-09.

Abstract P1-07-08: Young age and the risk of disease recurrence as assessed by the 70-gene signature – an analysis from the EORTC 10041/BIG 03-04 MINDACT trial

Purpose: Increased insight in tumor biology has revealed that not all young women are at high risk of disease recurrence. Therefore, in some patients extent of treatment could probably be safely scaled down. We aimed to evaluate the risk of breast cancer (BC) relapse according to the 70-gene signature (70-GS) result in relation to young age, in early-stage BC patients enrolled in the MINDACT trial.

Patients and Methods: The analyzed population consisted of enrolled BC patients in the MINDACT trial with available clinical (C), as per a modified version of Adjuvant!Online, and genomic (G), according to the 70-GS, risk assessments and known age (n=6693). Patients were categorized in three age groups; &lt;45 (young), 45-55 (peri-menopausal) and &gt;55 years (post-menopausal). Clinicopathological and treatment characteristics as well as gene expression were compared for the different age groups further split by corrected risk groups (C-low/G-low, C-low/G-high, C-high/G-low, C-high/G-high). Subsequently, the 5-year distant metastasis-free survival according to risk category was calculated.

Results: The study included 1100 patients &lt;45 (16%), 2272 aged 45-55 (34%) and 3321 patients &gt;55 years of age (50%). Median age of the young group was 41 (25.8-45.0) years. The young age group had a higher frequency of lymph node involvement (25% vs. 22% and 19%), poorly differentiated tumors (42% vs. 26% and 27%), ER-negative tumors (20% vs. 11% and 11%) and triple negative molecular IHC subtype (16% vs. 9% ad 8%). Median tumor size was the same across the 3 age groups (17mm). Of the 1100 young patients, 61% were C-high while the 70-GS assessed 48% as G-high. Overall, 31% were CL/GL (vs. 43% in other age groups), 9% CL/GH, 21% CH/GL and 40% CH/GH (vs. 24% and 25%).

In the discordant risk groups, chemotherapy (CT) allocation when randomized to no chemo occurred in 5% of young women as compared to 3% and 1% in the older age groups. Reason for non-compliance was 50/50 between patient refusal and PI decision.

Overall, the 5-year DMFS was 94.1% (95% CI 92.4-95.4) in &lt;45 age group, 95.3% (95% CI 94.2-96.1) in 45-55 and 94.9% (95% CI 94.0-95.6) in &gt;55. For the young patients, 5-year DMFS was 98.3% for the CL/GL (96.0-99.3), 97.4% in CL/GH (90.0-99.4), 95.5% in CH/GL (91.6-97.7) and 89.2% in CH/GH (85.6-92.0). In the older two age groups (45-55 and &gt;55), the 5-year DMFS rates were 97.8% (96.5.98.6) and 97.2% (96.2-98.0) for CL/GL, 93.9% (88.8-96.7) and 94.5% (91.0-96.7) for CL/GH, 94.5% (92.0-96.3) and 95.4% (93.5-96.8) for CH/GL and 92.0% (89.2-94.1) and 90.4% (88.0-92.4) for CH/GH, respectively. With 9 events in the &lt;45 group at a CH/GL risk, numbers were too small to evaluate chemotherapy effect in this population.

Conclusion: The use of the 70-GS reduces the proportion of patients characterized as high risk as compared to traditional clinical risk assessment (48% vs. 61%). Outcome was comparable for the 3 age categories with a very good 5-year DMFS of 95-98% in all GL groups. Performing the 70-GS provides clinically relevant information concerning the prognosis for young early-stage BC patients categorized as CH. These results add important new data to the limited available evidence on genomic expression in young BC patients.

Citation Format: Aalders K, Genbrugge E, Poncet C, Kuijer A, Pistilli B, Piccart M, Tryfonidis K, van Dalen T, Cardoso F, van 't Veer L, Rutgers E. Young age and the risk of disease recurrence as assessed by the 70-gene signature – an analysis from the EORTC 10041/BIG 03-04 MINDACT trial [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 P1-07-08.

Impact of gene-expression profiling in patients with early breast cancer when applied outside the guideline directed indication area

PURPOSE

In Dutch guidelines, gene expression profiles (GEP) are indicated in estrogen receptor positive early breast cancer patients in whom benefit of chemotherapy (CT) is uncertain based on traditional prognostic factors alone. Aim of the present study is to assess the use and impact of GEP on administration of adjuvant CT in breast cancer patients who have according to national guidelines a clear indication to either use or withhold adjuvant chemotherapy (clinical high or low risk).

METHODS

Clinical low- and high-risk patients, according to Dutch breast cancer guidelines, diagnosed between 2011 and 2014 were selected from the Netherlands Cancer Registry. Influence of GEP use and GEP test result on CT administration was assessed with logistic regression.

RESULTS

Overall, 26,425 patients were identified; 4.8% of patients with clinical low risk (444/9354), 7.5% of the patients with a clinical high risk (1281/17,071) received a GEP. GEP use was associated with significantly increased odds of CT administration in clinical low-risk patients (OR = 2.12 95% CI: 1.44-3.11). In clinical high-risk patients, GEP use was associated with a decreased frequency of CT administration (OR = 0.55, 95% CI: 0.48-0.63). Adherence to the GEP result was higher in clinical high-risk patients with a discordant GEP result as compared to clinical low-risk patients with a discordant GEP result: 71.7% vs. 52.2%, respectively.

CONCLUSION

GEP is frequently used outside the indicated area and significantly influenced the administration of adjuvant CT, although adherence to the test result was limited.

Characterisation of multifocal breast cancer using the 70-gene signature in clinical low-risk patients enrolled in the EORTC 10041/BIG 03-04 MINDACT trial

BACKGROUND

In multifocal breast cancer, guidelines recommend basing adjuvant systemic treatment decisions on characteristics of the largest lesion, disregarding multifocality as an independent prognosticator. We assessed the association between multifocal disease and both the 70-gene signature (70-GS), and distant metastasis-free survival (DMFS) in clinical low-risk breast cancer patients enrolled in the European Organisation for Research and Treatment of Cancer 10041/BIG 03-04 Microarray In Node-negative and 1 to 3 positive lymph node Disease may Avoid ChemoTherapy (MINDACT) trial.

PATIENTS AND METHODS

The analysed population consisted of enrolled patients in the MINDACT trial with clinical low-risk disease, defined by a modified Adjuvant! Online cut-off for the 10-year risk of recurrent disease or death. Eligibility criteria of MINDACT dictate that patients with multifocal disease could be included if the different lesions had similar pathological characteristics. The presence of multifocal disease was deducted from the case report form (CRF)-question for sum of diameter for all invasive tumour foci. Clinicopathological characteristics and gene expression of patients with unifocal and multifocal (largest lesion) disease were compared. Subsequently, the association between multifocal disease and the 70-GS was evaluated as well as the association between multifocality and 5-year DMFS.

RESULTS

The study included 3090 clinical low-risk patients with unifocal and 238 patients with multifocal disease. Apart from a higher prevalence of lobular tumours (21.8% versus 10.8%, by local pathology), we did not observe differences in baseline characteristics between multifocal and unifocal tumours. Patients with multifocal tumours were more likely to be at high genomic risk as compared to patients with unifocal tumours (22.7% versus 17.3%, odds ratio [OR] 1.45, 95% confidence interval [CI] 1.02-2.07, P = 0.038). We did not find a significant association between tumour focality and DMFS (97.1% for unifocal versus 96.9% for multifocal, hazard ratio [HR] = 1.55, 95% CI 0.68-3.46, P = 0.172), nor a signal for a potential interaction between the prognostic effect of the 70-GS and focality of the tumour regarding DMFS.

CONCLUSION

In the group of clinical low-risk MINDACT patients, multifocal tumours were more likely to have a high-risk 70-GS profile compared to unifocal tumours. We did not observe a significant interaction between multifocality and the 70-GS with respect to survival without distant metastasis in these patients.

Abstract P1-03-04: Concordance of local immunohistochemistry with TargetPrint microarray based assessment of ER, PR and Her2 and BluePrint molecular subtyping in the Symphony Triple A study

PURPOSE: A decade ago intrinsic biological breast cancer subtypes have been identified which have proven to be of clinical importance in terms of outcome and response to systemic treatment. The aim of the current study is to assess concordance between breast cancer subtypes determined by local immunohistochemistry (IHC) assessment of estrogen receptor (ER), progesterone receptor (PR) and Her2-receptor status and microarray based molecular subtyping in a subset of ER+ early stage breast cancer patients.

PATIENTS AND METHODS: In this prospective observational multicenter study information on local pathology assessment and BluePrint/TargetPrint results were obtained in ER+ Dutch early stage breast cancer patients in whom a 70-gene profile (MammaPrint) was used as they were enrolled in clinical trial based on the existence of controversy regarding the additional value of adjuvant CT. Local IHC assessment of ER, PR and Her2 status were compared with microarray based assessment (TargetPrint/BluePrint) of these characteristics. Reclassification of ER and PR overexpression was assessed by a McNemars test and by Spearman correlation. Furthermore, concordance between the clinical subtypes based on local pathology (Luminal-type: ER+/PR+/Her2-; Her2-type: Her2+ disease) and molecular subtyping was assessed.

RESULTS: Between January 2013 And December 2015 660 patients, treated in 31 hospitals, were enrolled. In 564 (85%) BluePrint and/or TargetPrint was performed in addition to the 70-GS. The majority of patients had ER+/Her2- disease and TargetPrint reclassified 1% (n = 7) of patients as ER-negative (r = 0,250, p &lt;0,001). TargetPrint reclassified 7% (n = 40) and 2% (n = 11) of patients for PR and Her2 status respectively (table 1, r = 0,580, p &lt;0,001 for PR

Table 1. Concordance between immunohistochemistry and TargetPrint. TargetPrint result (ER, PR and Her2 resp.)  ImmunohistochemistryPositiveNegativeOverall discordance (%)p-value*Estrogenreceptor status    Positive557 (99%)6 (1%)  Negativen.a.n.a.1%n.a.Progesterone receptor status    Positive474 (96%)18 (4%)  Negative22 (31%)49 (69%)7%0,636Her2 receptor status    Positive3 (30%)7 (70%)  Negative4 (3%)546 (97%)2%0,549Equivocal0 (0%)3 (1%)  * P-value represents results of the McNemar test.). Based on IHC 545 (98%) patients were regarded as luminal-type and the remaining 2% as Her2-type. BluePrint reclassified 2% of the clinical luminal-type patients: 4 (1%) patients were reclassified as basal-type and 3 (0%) patients as Her2-type. Of the clinical Her2-type patients 80% (n=8) was reclassified by BluePrint as molecular luminal-type.

Table 2. Concordance between clinical subtyping and molecular subtyping according to BluePrint.  BluePrint resultClinical SubtypeNo. ptsLuminalBasalHer2Luminal545539 (99%)4 (1%)3 (0%)Her2108 (80%)02 (20%)Note. Overall discordance 3%.

Conclusion: In the current study we observe a high concordance between microarray-based assessment of ER, PR and Her2 and local pathology in Dutch ER+ early stage breast cancer patients. In the small subset of ER+ patients who are considered candidates for 70 GS use and who have HER2+ tumors by IHC molecular typing of HER2 status is of additional value.

Citation Format: Kuijer A, Straver M, Elias S, Smorenburg C, Wesseling J, Linn S, Rutgers E, Siesling S, van Dalen T. Concordance of local immunohistochemistry with TargetPrint microarray based assessment of ER, PR and Her2 and BluePrint molecular subtyping in the Symphony Triple A study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-04.

Adjuvant systemic therapy in early breast cancer: impact of guideline changes and clinicopathological factors associated with nonadherence at a nation-wide level

Over recent years, adjuvant systemic treatment guidelines (AST) for early-stage breast cancer have changed considerably. We aimed to assess the impact of these guideline changes on the administration of AST in early-stage breast cancer patients and to what extent these guidelines are adhered to at a nation-wide level. We used Netherlands Cancer Registry data to describe trends in AST prescription, adherence to AST guidelines, and to identify clinicopathological determinants of nonadherence. Between 1990 and 2012, 231,648 Dutch patients were diagnosed with early breast cancer, of whom 124,472 received AST. Adjuvant endocrine treatment (ET) use increased from 23 % of patients (1990) to 56 % (2012), and chemotherapy from 11 to 44 %. In 2009-2012, 8 % of patients received ET and 3 % received chemotherapy without guideline indication. Conversely, 10-29 % of patients did not receive ET and chemotherapy, respectively, despite a guideline indication. Unfavorable clinicopathological characteristics generally decreased the chance of undertreatment and increased the chance for overtreatment. Remarkable was the increased chance of ET undertreatment in younger women (RR < 35 vs 60-69 years 1.79; 95 % CI 1.30-2.47) and in women with HER2+ disease (RR 1.64; 95 % CI 1.46-1.85). Over the years, AST guidelines expanded resulting in much more Dutch early breast cancer patients receiving AST. In the majority of cases, AST administration was guideline concordant, but the high frequency of chemotherapy undertreatment in some subgroups suggests limited AST guideline support in these patients.

Changes over time in the impact of gene-expression profiles on the administration of adjuvant chemotherapy in estrogen receptor positive early stage breast cancer patients: A nationwide study

Ten years ago gene-expression profiles were introduced to aid adjuvant chemotherapy decision making in breast cancer. Since then subsequent national guidelines gradually expanded the indication area for adjuvant chemotherapy. In this nation-wide study the evolution of the proportion of patients with estrogen-receptor positive (ER+) tumors receiving adjuvant chemotherapy in relation to gene-expression profile use in patient groups that became newly eligible for chemotherapy according to national guideline changes over time is assessed. Data on all surgically treated early breast cancer patients diagnosed between 2004-2006 and 2012-2014 were obtained from the Netherlands Cancer Registry. ER+/Her2- patients with tumor-characteristics making them eligible for gene-expression testing in both cohorts and a discordant chemotherapy recommendation over time (2004 guideline not recommending and 2012 guideline recommending chemotherapy) were identified. We identified 3,864 patients eligible for gene-expression profile use during both periods. Gene-expression profiles were deployed in 5% and 35% of the patients in the respective periods. In both periods the majority of patients was assigned to a low genomic risk-profile (67% and 69%, respectively) and high adherence rates to the test result were observed (86% and 91%, respectively). Without deploying a gene-expression profile 8% and 52% (p <0.001) of the respective cohorts received chemotherapy while 21% and 28% of these patients received chemotherapy when a gene-expression profile was used (p 0.191). In conclusion, in ER+/Her2- early stage breast cancer patients gene-expression profile use was associated with a consistent proportion of patients receiving chemotherapy despite an adjusted guideline-based recommendation to administer chemotherapy.