Adjuvant chemotherapy in patients with invasive lobular carcinoma and use of the 21-gene recurrence score: A National Cancer Database analysis.

BACKGROUND: Invasive lobular carcinoma (ILC) is traditionally considered less responsive to chemotherapy. Although the Oncotype recurrence score (RS) has been validated to identify high-risk patients who benefit from chemotherapy, some studies have questioned its relevance in patients with ILC. The objective of this study was to better characterize potential use of the RS in these patients. METHODS: The National Cancer Database was used to identify women with stage I through III, T1 through T3, N0 or N1, hormone receptor-positive, HER2-negative ILC or invasive ductal carcinoma (IDC) who had an available RS between 2010 and 2016. Multivariable Cox regression was used to model the effect of variables on 5-year overall survival (OS). The Kaplan-Meier method was used to estimate OS according to the RS, nodal status, and chemotherapy. RESULTS: In total, 15,763 patients with ILC and 100,070 with IDC were identified. The mean age of patients with ILC and IDC was 59.2 ± 9.1 and 57.2 ± 9.8, respectively. A lower percentage of patients with ILC versus those with IDC had a high RS, defined as >25 (6.6% vs 16.0%; P < .0001). ILC patients with a high RS who had N0 or N1 disease received approximately 10% less chemotherapy compared with similar patients who had IDC. The results indicated that the RS had statistically significant prognostic value for patients with ILC. In addition, an absolute OS advantage was correlated with the receipt of chemotherapy by patients with ILC who had a high RS with N0 or N1 disease. CONCLUSIONS: Patients with ILC who have a high RS are treated less often with chemotherapy compared with similar patients who have IDC. Nevertheless, the RS has a prognostic as well as a predictive value in ILC, with an association between OS benefit and chemotherapy receipt in patients who have ILC with a high RS, especially if they have N1 disease. LAY SUMMARY: Invasive lobular carcinoma (ILC) is a subtype of breast cancer comprising about 15% of cases. The Oncotype recurrence score (RS) is a genetic test of breast tumors that helps predict which patients might benefit from chemotherapy. Some have doubted the relevance of the RS for patients with ILC. In this study, the authors show that the RS is relevant for patients who have ILC. The RS has the potential of predicting the risk of recurrence and identifying patients with ILC who might benefit from chemotherapy.

Prognostic value of the 21-gene recurrence score for regional recurrence in patients with estrogen receptor-positive breast cancer.

PURPOSE: To evaluate the prognostic value of the 21-gene recurrence score (RS) for regional recurrence (RR) in patients with estrogen receptor-positive breast cancer. METHODS: We reviewed the medical records of 446 patients who underwent 21-gene RS assay after breast-conserving surgery or mastectomy. The high-RS group was defined as patients who were (1) older than 50 years with an RS of 26 or higher, or (2) 50 years or younger with an RS of 16 or higher. RESULTS: The 5-year rates of local recurrence (LR), RR, and distant metastasis (DM) were 2.2%, 2.7%, and 4.7%, respectively. The 5-year overall survival (OS) rate was 99.1%. Of the patients, 269 (60.3%) had low-RS, while 177 (39.7%) had high-RS. The 5-year OS rate of the high-RS group was significantly lower than that of the low-RS. The 5-year rates of RR and DM in the high-RS group were significantly higher than those in the low-RS group, while the LR rates did not differ significantly. In multivariable analysis, the high-RS group had a significant relationship with increased RR rate (p = 0.037). Patients who had both high-RS and clinical high-risk features had a significantly higher 5-year RR rate (7.9%) compared with other groups. CONCLUSIONS: High-RS was an independent risk factor for RR. The significantly higher RR rate of patients with both high-RS and clinical high-risk features compared with other groups suggests that this patient group can be a potential candidate for regional nodal irradiation.

The 21-gene recurrence score in node-positive, hormone receptor-positive, HER2-negative breast cancer: a cautionary tale from an NCDB analysis.

PURPOSE: The 21-gene recurrence score assay (RS) has not been prospectively validated to predict adjuvant chemotherapy benefit in hormone receptor-positive (HR+), HER2-negative (HER2-), node-positive breast cancer patients. Nevertheless, de-escalation based on RS has been demonstrated and partially advocated by retrospective data. The purpose of this study was to identify subgroups of node-positive patients with low to intermediate RS who still benefit from adjuvant chemotherapy. METHODS: The National Cancer Database was used to identify 28,591 women with stage I-III, T1-T3, N1, HR+, HER2- breast cancer and a RS ≤ 25 between 2010 and 2016. Univariate and multivariate analyses were used to identify variables correlating with chemotherapy use and 5-year survival. Subgroup analysis was performed to discern patients in whom the use of adjuvant chemotherapy correlated with better survival. RESULTS: A 35% decline in chemotherapy use was observed from 2010 to 2016. Patients with younger age, higher RS, larger tumors and more positive lymph nodes, and those treated by mastectomy, axillary lymph node dissection and radiation, were more likely to receive chemotherapy. Chemotherapy use was associated with an improved 5-year survival (HR = 1.63, 95% CI 1.28-2.07). Upon subgroup analysis, this association was lost in patients > 70 years and those with a RS ≤ 11, while patients ≤ 70 with a RS of 12-25 treated with chemotherapy had an absolute 5-year survival advantage of 3.0% (HR = 1.91, 95% CI 1.42-2.57). CONCLUSION: Clinicians should be cautious when considering omission of adjuvant chemotherapy in patients ≤ 70 years, with HR+, HER2-, N1 tumors and a RS 12-25, at least until the results of the anticipated RxPONDER trial become available.

A nomogram to predict the high-risk RS in HR+/HER2-breast cancer patients older than 50 years of age.

BACKGROUND: The 21-gene recurrence score (RS) testing can predict the prognosis for luminal breast cancer patients. Meanwhile, patients > 50 years with RS > 25 have improved survival with adjuvant chemotherapy. The current study aimed to develop a nomogram with routine parameters to predict RS. METHODS: We included patients diagnosed with hormone receptor (HR)-positive, human epidermal growth factor receptor-2 (HER2)-negative who underwent the 21-gene RS testing and aged > 50 years. The primary outcome was high-risk RS (> 25). Univariate and multivariate analyses were performed to identify significant predictors. A predictive nomogram based on logistic model was developed and evaluated with receiver operating characteristic (ROC) curves. The nomogram was internally validated for discrimination and calibration with bootstrapping method, and externally validated in another cohort. We then assessed the nomogram in different subgroups of patients and compared it with several published models. RESULTS: A total of 1100 patients were included. Five clinicopathological parameters were used as predictors of a high-risk RS, including tumor grade, histologic subtype, ER expression, PR expression, and Ki-67 index. The area under the curve (AUC) was 0.798 (95% CI 0.772-0.825) and optimism adjusted AUC was 0.794 (95% CI 0.781-0.822). External validation demonstrated an AUC value of 0.746 (95% CI 0.685-0.807), which had no significant difference with the training cohort (P = 0.124). Calibration plots indicated that the nomogram-predicted results were well fitted to the actual outcomes in both internal and external validation. The nomogram had better discriminate ability in patients who had tumors > 2 cm (AUC = 0.847, 95% CI 0.804-0.890). When compared with four other existing models, similar AUC was observed between our nomogram and the model constructed by discriminate Lee et al. CONCLUSIONS: We developed a user-friendly nomogram to predict the high-risk RS in luminal breast cancer patients who were older than 50 years of age, which could guide treatment decision making for those who have no access to the 21-gene RS testing.

Efficacy of adjuvant chemotherapy stratified by age and the 21-gene recurrence score in estrogen receptor-positive breast cancer.

BACKGROUND: The 21-gene recurrence score (RS) can predict chemotherapy benefit in estrogen receptor-positive, human epidermal growth factor receptor-2-negative (ER+/HER2-) early breast cancer patients. Age would influence the interaction between RS and chemotherapy effect. The current study aimed to determine RS thresholds which were predictive of chemotherapy benefit in young and old women, respectively. METHODS: Patients diagnosed with pN0-1, ER+/HER2- breast cancer between 2009 and 2016 were retrospectively reviewed. Propensity score matching was performed according to chemotherapy usage. After stratifying patients with different cutoffs of age, the RS threshold indicating chemotherapy benefit in each age strata were determined by cox proportional hazard models. RESULTS: A total of 1227 patients were included. The median age was 58 years and the median RS was 24. After matching, the RS thresholds suggesting chemotherapy benefit varied with age. For patients ≤55 years, chemotherapy benefit was observed in those having RS > 25 (P = 0.03), with 4-year invasive disease-free survival (IDFS) of 97.0 and 89.3% in patients receiving chemotherapy or not. While patients derived no benefit from chemotherapy if they had RS ≤25 (P = 0.66, 4-year IDFS: 95.3% vs. 94.6%). For patients > 55 years, adjuvant chemotherapy was associated with better prognosis in those with RS > 36 (P = 0.014, 4-year IDFS: 94.7% vs. 76.2%), but not in those having RS ≤36 (P = 0.13, 4-year IDFS: 92.3% vs. 95.8%). CONCLUSIONS: Old patients need higher RS thresholds to demonstrate the chemotherapy benefit. Further efforts are warranted to investigate the association between age and predictive RS thresholds.

Genomic expression assay testing among American Indian and Alaska Native women with breast cancer.

BACKGROUND: Breast cancer is one of the most common causes of cancer mortality for all women, including American Indian and Alaska Native (AI/AN) women. The use of the 21-gene recurrence score (RS) appears to be predictive of the benefit of chemotherapy for women with estrogen receptor (ER)-positive breast cancer. The objective of the current study was to compare RS testing between AI/AN and non-Hispanic White (NHW) women with breast cancer. METHODS: The Surveillance, Epidemiology, and End Results program was used to identify women with ER-positive breast cancer from 2004 through 2015. Multivariable logistic regression was used to evaluate factors associated with RS use, with high-risk RS, and with chemotherapy use among those with a high-risk RS. RESULTS: A total of 363,387 NHW patients and 1951 AI/AN patients with ER-positive breast cancer were identified. AI/AN women were found to be less likely to undergo RS testing and, when tested, were more likely to have a high-risk RS. In the multivariable logistic regression analysis, AI/AN women were found to be significantly more likely to have a high-risk RS (odds ratio,1.28; 95% confidence interval, 1.01-1.66). Among untested women, chemotherapy use was higher for AI/AN women; however, the use of chemotherapy was not found to be significantly different between the groups with a high-risk RS. Using Cox proportional hazards models, AI/AN race was found to be significantly associated with worse overall survival. CONCLUSIONS: AI/AN women were less likely to undergo RS testing compared with NHW women and were more likely to have a high-risk RS. Reversing the disparity in genomic expression assay testing is critical to ensure guideline-based breast cancer treatment and improve survival rates for AI/AN women with breast cancer.

Correlation of circulating or disseminated tumor cells with the Oncotype DX Recurrence Score.

PURPOSE: New biomarkers are emerging to predict recurrence risk in women with early-stage breast cancer. High Oncotype DX Recurrence Score® (RS) is associated with worse disease-free and overall survival. Similarly, circulating tumor cells (CTCs, blood) and disseminated tumor cells (DTCs, bone marrow) have prognostic value in breast cancer. We investigated the association between high RS and CTCs or DTCs. METHODS: Using a prospective database, we evaluated patients with hormone receptor-positive/HER2-negative, node-negative invasive breast cancer from 1/2005 to 1/2017. RS was classified using TAILORx study cutoff points: low (< 11), intermediate (11-25), and high (> 25). CTCs were assessed using CellSearch® and DTCs using cytospin specimens of bone marrow aspirates. Positive result was defined as one or more CTCs or DTCs identified. Chi-square analyses were utilized to evaluate the relationship between RS and CTCs or DTCs. RESULTS: 233 patients were identified from a prospective database, of which 96 had RS results. Of these patients, 88 had CTC results and 58 had DTC results. CTCs were detected in 17/88 (19%) patients, while DTCs were detected in 20/58 (34%). Patients with high RS were not more likely to have CTCs (18%) compared to patients with low/intermediate RS (20%; p = 0.919). Similarly, high RS was not associated with DTC detection, with DTCs present in 40% of patients with high RS versus 33% with low/intermediate RS (p = 0.687). In the subgroup of patients ≤ 50 years, no associations were found between high RS and CTCs (p = 0.383) or DTCs (p = 0.234). CONCLUSIONS: High Oncotype DX RS did not correlate with CTCs in blood or DTCs in bone marrow in our study.

The prognostic and predictive role of 21-gene recurrence scores in hormone receptor-positive early-stage breast cancer.

Over the past two decades, gene expression profiling of breast cancer has emerged as an important tool in early-stage breast cancer management. The approach provides important information on underlying biological mechanisms, breast cancer classification, future risk potential of developing recurrent metastatic disease, and provides beneficial clues for adjuvant chemotherapy in hormone receptor (HR) positive breast cancer. Of the commercially available genomic tests for breast cancer, the prognostic and predictive value of 21-gene recurrence score tests have been validated using both retrospective data and prospective clinical trials. In this paper, we reviewed the current evidence on 21-gene expression profiles for HR-positive HER2-negative early-stage breast cancer management. We show that current evidence supports endocrine therapy alone as an appropriate adjuvant systemic therapy for approximately 70% of women with HR-positive, HER2-negative, node-negative breast cancer. Evolving evidence also suggests that 21-gene recurrence scores have predictive values for node-positive breast cancer and that chemotherapy can be avoided in more than half of women with nodes 1 to 3 positive HR-positive breast cancer. Furthermore, retrospective data also supports the predictive role of 21-gene recurrence scores for adjuvant radiation therapy. A prospective trial in this area is ongoing.

Multigene testing in breast cancer: What have we learned from the 21-gene recurrence score assay?

Most invasive breast cancers express hormone receptors (HR) and typically have a favorable prognosis following endocrine therapy. Patients at a higher risk of recurrence can be identified by multigene prognostic classifiers such as the 21-gene recurrence score (RS) assay, 70-gene prognostic signature, PAM-50, 12-gene molecular score, and others. The 21-gene RS assay (Oncotype Dx™, Genomic Health, Redwood City, CA) has level I clinical evidence and is the most widely used multigene assay in North America. The RS assay is based on reverse transcriptase polymerase chain reaction that can be performed on the RNA isolated from formalin-fixed paraffin-embedded tissue. It evaluates the expression of 16 cancer-related genes developed based on a multi-step approach. Due to its ability to assess recurrence risk and predict potential benefit from chemotherapy, the assay is recommended for patients with node-negative, HR-positive, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer by the American Society of Clinical Oncology, National Comprehensive Cancer Network clinical practice guidelines in oncology, European Society for Medical Oncology clinical practice guidelines, and St. Gallen consensus panel guidelines. The RS assay has also been incorporated in the prognostic stage groups in the 8th edition of the American Joint Commission of Cancer staging manual in order to provide essential genomic information for optimal treatment decisions. This review will focus on the utility of the RS assay in HR-positive and HER2-negative breast cancer patients, including risk of distant and locoregional recurrence in node-negative and node-positive tumors, association with radiotherapy, special subtypes of breast cancer, practical issues related to selecting tumors for testing, and overview of the recently published TailorX (Trial Assigning IndividuaLized Options for treatment [Rx]) results.

Adjuvant chemotherapy and survival among patients 70 years of age and younger with node-negative breast cancer and the 21-gene recurrence score of 26-30.

BACKGROUND: The benefits of chemotherapy in node-negative, hormone receptor-positive, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients with the 21-gene recurrence score (RS) of 18-30, particularly those with RS 26-30, are not known. METHODS: Using the Surveillance, Epidemiology, and End Results (SEER) data, we retrospectively identified 29,137 breast cancer patients with the 21-gene RS of 18-30 diagnosed between 2004 and 2015. Mortality risks according to the RS and chemotherapy use were compared by the Kaplan-Meier method and Cox's proportional hazards model. RESULTS: Among the breast cancer patients with the RS 18-30, 21% of them had RS 26-30. Compared to breast cancer patients with RS 18-25, patients with RS 26-30 had more aggressive tumor characteristics and chemotherapy use and increased risk of breast cancer-specific mortality and overall mortality. In breast cancer patients who were aged ≤ 70 years and had RS of 26-30, chemotherapy administration was associated with a 32% lower risk of breast cancer-specific mortality (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.47-0.99) and a 42% lower risk of overall mortality (HR, 0.58; 95% CI, 0.44-0.76). Survival benefits were most pronounced in breast cancer patients who were younger or had grade III tumor. CONCLUSIONS: The 21-gene RS of 18-30 showed heterogeneous outcomes, and the RS 26-30 was a significant prognostic factor for an increased risk of mortality. Adjuvant chemotherapy could improve the survival of node-negative, hormone receptor-positive, and HER2-negative breast cancer patients with the 21-gene RS 26-30 and should be considered for patients, especially younger patients or patients with high-grade tumors.

Impact of biomarkers and genetic profiling on breast cancer prognostication: A comparative analysis of the 8th edition of breast cancer staging system.

The 8th edition of the American Joint Committee on Cancer (AJCC) staging guidelines combine traditional TNM system with biomarkers to reflect our current understanding of tumor biology and targeted therapy. In this study, we investigated the impact of the TNM + Biomarkers staging system and the additive value of Oncotype Dx™ genomic profile recurrence score (RS) (TNM + Biomarkers+RS <11) for the staging of breast cancer (BC) using data from two tertiary referral cancer centers. Compared to TNM alone, the TNM + Biomarkers system changed the stage group in 32.7% of BCs (27% downstage, 5.7% upstage). Most (98.3%) of the downstaged BCs were estrogen receptor (ER)+/progesterone receptor (PR)+, whereas 78% of the upstaged BCs were ER-/PR-/human epidermal growth factor receptor 2 (HER2)-. Compared to TNM + Biomarkers staging, the addition of genetic profile data (TNM + Biomarker+RS <11) downstaged only <1% BCs. Our analysis suggests that for T1-T2N0 ER+/HER2- BCs, Oncotype Dx™ RS <11 provides added value as a staging parameter only in a very small group of cases compared to TNM + Biomarkers alone.

Tumor grade and progesterone receptor status predict 21-gene recurrence score in early stage invasive breast carcinoma.

PURPOSE: The 21-gene recurrence score (RS) assay is increasingly utilized to predict the risk of recurrence in early stage estrogen receptor (ER)-positive breast cancer. We hypothesize that tumor grade and progesterone receptor (PR) status predict RS categorization. METHODS: We identified women between the ages of 18 and 74 years with stage I or II, ER-positive, invasive carcinoma of the breast from the Surveillance Epidemiology End-Results database from 2010 to 2013. Multivariable logistic regression was performed to determine factors associated with high-risk RS. RESULTS: We identified 42,530 patients that met inclusion criteria. Multivariable logistic regression demonstrated that grade I tumors [OR (odds ratio) 0.33, 95% CI (confidence interval) 0.31-0.37] and PR positive (PR+) status (OR 0.16, 95% CI 0.15-0.17) were significantly less likely to be associated with high-risk RS. Of patients with grade I PR+ tumors, 1% was in the high-risk group by the traditional cutoffs and 4% was in the high-risk group by the TAILORx cutoffs. The percentage of patients with high-risk RS remained low for grade I PR+ tumors regardless of age, race, tumor size, and lymph node status. CONCLUSIONS: We found that grade I PR+ tumors are associated a < 5% probability of having high-risk RS regardless of other patient demographic or pathologic factors. This suggests that the histologic factors of grade and PR status should be taken into consideration before ordering the 21-gene recurrence score assay.

Comparisons of tumor-infiltrating lymphocyte levels and the 21-gene recurrence score in ER-positive/HER2-negative breast cancer.

BACKGROUND: Recent studies have shown that tumors with extensive tumor-infiltrating lymphocytes (TILs) have a higher probability of pathologic complete response, even in luminal/human epidermal growth factor 2 (HER2)-negative breast cancer. We compared TIL levels and the 21-gene recurrence score (RS) in estrogen receptor (ER)-positive/HER2-negative breast cancer. METHODS: We evaluated the percentage of stromal TILs in 198 ER-positive/HER2-negative patients in whom RS was obtained by examining slides of surgical specimens by standardized methodology proposed by the international TIL Working Group. TIL levels were categorized as high (≥ 60%), intermediate (11-59%), or low (≤ 10%). All tumors were treatment-naïve. RESULTS: Ninety-seven (49.0%), 88 (44.4%), and 13 patients (6.6%) had low, intermediate, and high TIL levels, respectively. There was a significant but weak correlation between continuous RS and continuous TIL levels (Pearson's R = 0.201, p = 0.004). The mean RS was significantly highest in high TIL tumors (17.8 ± 10.7 in low TIL tumors, 19.4 ± 8.7 in intermediate TIL tumors, and 26.2 ± 8.2 in high TIL tumors; p = 0.014). However, when we compared categorized RS and TIL levels, we found that tumors with high TIL levels tended to have higher RS (≥ 26) but it was not significant (p = 0.155). Furthermore, multivariate analysis revealed that high RS was not an independent factor associated with high TIL levels. Chemo-endocrine therapy was more frequently performed among patients with high TILs and less frequently among those with low or intermediate TILs (p <  0.001). CONCLUSIONS: Despite of a weak correlation between continuous TIL levels and RS, we found that tumors with high TIL levels tended to have a higher RS in ER-positive/HER2-negative breast cancer. Further study is warranted considering the clinical outcomes.

Breast carcinoma with 21-gene recurrence score lower than 18: rate of locoregional recurrence in a large series with clinical follow-up.

BACKGROUND: The 21-gene recurrence score (RS) assay determines the benefit of adding chemotherapy to endocrine therapy for patients with early stage, estrogen receptor (ER)-positive, HER2-negative breast cancer. The RS risk groups predict the likelihood of distant recurrence and have recently been associated with an increased risk of locoregional recurrence (LRR). This study analyzed clinicopathologic features of patients with low RS and LRR. METHODS: In our institutional database, we identified 1396 consecutive female patients with lymph node negative, ER+/HER2- invasive breast carcinoma and low RS (<18) results, treated at our center from 2008 to 2013. We collected data on clinicopathologic features, treatment and outcome. RESULTS: The median patient age was 57 years (range 22-90). The median tumor size was 1.2 cm (range 0.3-5.8). Overall, 66.6% (930/1396) women were treated with breast conserving surgery (BCS) and radiation therapy, 3.4% (48/1396) with BCS alone, 29.7% (414/1396) with total mastectomy, and 0.3% (4/1396) with total mastectomy and radiation therapy. Most patients (84.8%; 1184/1396) received endocrine therapy alone, 12.1% (169/1396) were treated with chemotherapy plus endocrine therapy, and only 3.1% (43/1396) received no systemic therapy. At a median follow-up of 52 months, 0.9% (13/1396) of patients developed LRR. Sites of LRR included the ipsilateral breast (n = 8), chest wall (n = 3), axillary node (n = 1), and internal mammary node (n = 1). All patients with LRR had negative resection margins at the initial surgery. The rate of LRR in patients treated with adjuvant endocrine therapy alone was 0.7% (8/1184). All eight patients received standard local treatment. Three patients had lymphovascular invasion but no other significant risk factors for LRR were identified. CONCLUSIONS: Our study of node negative, ER+/HER2- breast cancer patients with low RS observed extremely low rates of LRR: 0.9% (13/1396) in the whole cohort and 0.7% (8/1184) in patients treated with endocrine therapy alone. As the largest series to date, we report detailed clinicopathologic data and clinical outcomes of this cohort and provide a comprehensive characterization of patients who developed LRR.

Diffusion-weighted MRI characteristics associated with prognostic pathological factors and recurrence risk in invasive ER+/HER2- breast cancers.

BACKGROUND: Hormone receptor-positive breast cancer is the most common subtype; better tools to identify which patients in this group would derive clear benefit from chemotherapy are needed. PURPOSE: To evaluate the prognostic potential of diffusion-weighted MRI (DWI) by investigating associations with pathologic biomarkers and a genomic assay for 10-year recurrence risk. STUDY TYPE: Retrospective. SUBJECTS: In all, 107 consecutive patients (from 2/2010 to 1/2013) with estrogen receptor (ER)-positive/HER2neu-negative invasive breast cancer who had the 21-gene recurrence score (RS) test (Oncotype DX, Genomic Health). FIELD STRENGTH/SEQUENCE: Each subject underwent presurgical 3T breast MRI, which included DWI (b = 0, 800 s/mm2 ). ASSESSMENT: Apparent diffusion coefficient (ADC) and contrast-to-noise ratio (CNR) were measured for each lesion by a fifth year radiology resident. Pathological markers (Nottingham histologic grade, Ki-67, RS) were determined from pathology reports. Medical records were reviewed to assess recurrence-free survival. STATISTICAL TESTS: RS was stratified into low (<18), moderate (18-30), and high (>30)-risk groups. Associations of DWI characteristics with pathologic biomarkers were evaluated by binary or ordinal logistic regression, as appropriate, with adjustment for multiple comparisons. Post-hoc comparisons between specific groups were also performed. RESULTS: ADCmean (odds ratio [OR] = 0.61 per 1 standard deviation [SD] increase, adj. P = 0.044) and CNR (OR = 1.76 per 1-SD increase, adj. P = 0.026) were significantly associated with increasing tumor grade. DWI CNR was also significantly associated with a high (Ki-67 ≥14%) proliferation rate (OR = 2.55 per 1-SD increase, adj. P = 0.026). While there were no statistically significant linear associations in ADC (adj. P = 0.80-0.85) and CNR (adj. P = 0.56) across all three RS groups by ordinal logistic regression, post-hoc analyses suggested that high RS lesions exhibited lower ADCmean (P = 0.037) and ADCmax (P = 0.004) values and higher CNR (P = 0.008) compared to lesions with a low or moderate RS. DATA CONCLUSION: DWI characteristics correlated with tumor grade, proliferation index, and RS, and may potentially help to identify those with highest recurrence risk and most potential benefit from chemotherapy. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage 3 J. Magn. Reson. Imaging 2017.

Associations between use of the 21-gene recurrence score assay and chemotherapy regimen selection in a statewide registry.

BACKGROUND: The 21-gene recurrence score (RS) assay predicts response to adjuvant chemotherapy in patients with early-stage, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative invasive breast cancer, but to the authors' knowledge, the role of the assay in guiding the selection of chemotherapy regimen has not been established. The current study was conducted to examine patterns of use of the RS assay for selecting chemotherapy regimens across a statewide registry from 2006 through 2013. METHODS: Demographic, pathologic, and treatment data were abstracted from medical records for 16,666 women with breast cancer who were treated at 25 hospital systems across Michigan that were participating in the Michigan Breast Oncology Quality Initiative. Treatment patterns were examined based on the RS assay test result. RESULTS: Approximately 25% of patients with lymph node-negative disease who underwent testing with the RS assay and who were treated with chemotherapy received an anthracycline-based regimen, compared with 49% of patients with lymph node-negative disease who were treated with chemotherapy and who had not undergone testing with the RS assay. Of those patients with lymph node-positive disease who underwent testing with the RS assay and who received chemotherapy, 31% received an anthracycline-based regimen. In comparison, 71% of patients with lymph node-positive, chemotherapy-treated disease who did not undergo testing received an anthracycline. From 2006 through 2013, there was a statistically significant decrease in the use of anthracycline-containing regimens in both patients with lymph node-negative and lymph node-positive disease. CONCLUSIONS: Use of anthracycline-containing chemotherapy regimens in eligible patients appears to vary with use of the RS assay, despite the lack of evidence supporting use of the assay to guide regimen selection. Results of ongoing prospective trials should help to define the role of the RS assay in this setting. Cancer 2017;123:948-56. © 2016 American Cancer Society.

21-Gene recurrence score and locoregional recurrence in lymph node-negative, estrogen receptor-positive breast cancer.

BACKGROUND/PURPOSE: The 21-gene recurrence score (RS) assay evaluates the likelihood of distant recurrence and benefit of chemotherapy in lymph node-negative, estrogen receptor (ER)-positive, HER2-negative breast cancer patients. The RS categories are associated with the risk of locoregional recurrence (LRR) in some, but not all studies. METHODS: We reviewed the institutional database to identify consecutive female patients with node-negative, ER+/HER2- breast carcinoma tested for the 21-gene RS assay and treated at our center from 2008 to 2013. We collected data on clinicopathologic features, treatment, and outcome. Statistical analysis was performed using SAS version 9.4 or R version 3.3.2. RESULTS: Of 2326 patients, 60% (1394) were in the low RS group, 33.4% (777) in the intermediate RS group, and 6.6% (155) in the high RS group. Median follow-up was 53 months. A total of 44 LRRs were observed, with a cumulative incidence of 0.17% at 12 months and 1.6% at 48 months. The cumulative incidence of LRR at 48 months was 0.84%, 2.72% and 2.80% for low, intermediate, and high RS groups, respectively (p < 0.01). Univariate analysis showed that the risk of LRR was associated with the RS categories (p < 0.01), T stage (p < 0.01) and lymphovascular invasion (LVI) (p = 0.009). There was no difference in LRR rates by initial local treatment (total mastectomy vs. breast-conserving surgery plus radiation therapy). The RS remained significantly associated with LRR after adjusting for LVI and T stage. Compared to patients with low RS, the risk of LRR was increased more than 4-fold (hazard ratio: 4.61, 95% CI 1.90-11.19, p < 0.01), and 3-fold (hazard ratio: 2.81, 95% CI 1.41-5.56, p < 0.01) for high and intermediate risk categories, respectively. CONCLUSIONS: Our study confirms that RS is significantly associated with the risk of LRR in node-negative, ER+/HER2- breast cancer patients. Our findings suggest that in addition to its value for prognostic stage grouping and decision-making regarding adjuvant systemic therapy, the role of the RS in identifying patients not requiring radiotherapy should be studied.

The influence of 21-gene recurrence score assay on chemotherapy use in a population-based sample of breast cancer patients.

PURPOSE: To quantify the influence of RS assay on changing chemotherapy plans in a general practice setting using causal inference methods. METHODS: We surveyed 3880 newly diagnosed breast cancer patients in Los Angeles and Georgia in 2013-14. We used inverse propensity weighting and multiple imputations to derive complete information for each patient about treatment status with and without testing. RESULTS: A half of the 1545 women eligible for testing (ER+ or PR+, HER2-, and stage I-II) received RS. We estimate that 30% (95% confidence interval (CI) 10-49%) of patients would have changed their treatment selections after RS assay, with 10% (CI 0-20%) being encouraged to undergo chemotherapy and 20% (CI 10-30%) being discouraged from chemotherapy. The subgroups whose treatment selections would be changed the most by RS were patients with positive nodes (44%; CI 24-64%), larger tumor (43% for tumor size >2 cm; CI 23-62%), or younger age (41% for <50 years, CI 23-58%). The assay was associated with a net reduction in chemotherapy use by 10% (CI 4-16%). The reduction was much greater for women with positive nodes (31%; CI 21-41%), larger tumor (30% for tumor size >2 cm; CI 22-38%), or younger age (22% for <50 years; CI 9-35%). CONCLUSION: RS substantially changed chemotherapy treatment selections with the largest influence among patients with less favorable pre-test prognosis. Whether this is optimal awaits the results of clinical trials addressing the utility of RS testing in selected subgroups.

The 21-gene recurrence score in special histologic subtypes of breast cancer with favorable prognosis.

BACKGROUND/PURPOSE: The 21-gene recurrence score (RS) assay predicts the likelihood of distant recurrence and chemotherapy benefit in early-stage, estrogen receptor (ER)-positive, HER2-negative breast cancer. Data on the RS of special histologic subtypes of invasive breast carcinoma with favorable prognosis are limited. METHODS: We reviewed our institutional database to identify patients with special histologic subtypes of breast cancer associated with favorable prognosis and available RS results. Our cohort consists of fifty-seven women: thirty-three patients with pure mucinous carcinoma (MC), ten with tubular carcinoma (TC), nine with encapsulated papillary carcinoma (EPC), and five with solid papillary carcinoma (SPC). RESULTS: Most (44/57, 77.2%) carcinomas had low RS (≤17), and none had high RS (≥31). All EPCs had low RS, but other subtypes had RS 18-30. Higher RS was associated with lower progesterone receptor (PR) expression by immunohistochemistry and lower PR mRNA scores (P ≤ 0.007). No morphologic feature (tumor grade, biopsy site changes, cellular stroma, inflammatory cells) was associated with RS ≥ 18. At a median follow-up of 40 months, the distant recurrence-free survival was 100%. One patient with SPC developed locoregional recurrence at 22 months. CONCLUSIONS: As the largest series to date, our study raises the question of whether the RS assay is necessary for breast cancers with favorable histology. Reflex testing of node-negative, ER+/HER2- breast cancers may be deferred for these special histologic subtypes, emphasizing the need for multidisciplinary discussions between breast pathologists and other members of the breast cancer team.

Clinical Application of Detecting 21-Gene Recurrence Score in Predicating Prognosis and Therapy Response of Patients with Breast Cancer from Two Medical Centers.

To determine the most suitable strategy in treating patients with invasive breast cancer from Northwest China. Lower recurrence score (RS) correlated with lower recurrence ratio. Patients having a medium-high 21-gene RS who received adjuvant therapy presented lower recurrence risk. Younger patients having RS results (⩾31) tended to accept adjuvant therapy more often, however, those having intermediate RS results were inclined to wait and did not receive chemotherapy. These results suggested that RS-based precision medicine will allow individualized diagnosis and treatment, resulting in better outcomes and preserved medical resources.