In the era of genomics, should tumor size be reconsidered as a criterion for neoadjuvant chemotherapy?

The Added Prognostic Value of Oncotype Recurrence Score to AJCC Prognostic Staging System in Stage III ER+/HER2- Breast Cancer

INTRODUCTION

Prognostic prediction based on prognostic stage (PS) with the Oncotype DX recurrence score (RS) has not been validated in stage III ER+/HER2- breast cancer. This study aimed to evaluate the added prognostic significance of RS incorporated with the PS system and to compare the prognostic prediction improvement with anatomic TNM stage (AS) using nomogram construction.

METHODS

The SEER database was indexed to identify ER+/HER2- invasive ductal or lobular breast cancer in AS IIIA-IIIC with RS results diagnosed from 2004 to 2013. Patients with RS < 18, 18-30 and > 30 were categorized into low-, intermediate- and high-risk RS groups. Comparisons of the distribution of clinical-pathologic characteristics among RS risk groups were performed using Pearson's chi-square test. Breast cancer-specific survival (BCSS) was estimated using the Kaplan-Meier method and compared across RS or PS by log-rank test. Cox regression was used to evaluate the factors independently related to BCSS. A nomogram comprised of PS and RS was constructed with discrimination, calibration and clinical benefit evaluated.

RESULTS

Altogether 629 patients who received RS were enrolled. There were 326 cases (51.8%) with low-risk RS, 237 (37.7%) with intermediate-risk RS and 66 (10.5%) with high-risk RS; 344 patients (54.7%) had PS IB, 84 (13.4%) had IIB, 150 (23.8%) had IIIA, 46 (7.3%) had IIIB, and only 5 had (0.8%) IIIC. Both PS and RS were independent prognostic factors for BCSS. There were significant or trends of differences in survival among RS within subtypes stratified by PS. There were significant differences in survival among PS only within intermediate-risk RS. A nomogram prediction 5-year BCSS was constructed with a c-index of 0.811. Lower histologic grade, positive PR and fewer positive lymph nodes were independently correlated with low-risk RS.

CONCLUSION

PS incorporated with RS had improved prognostic significance for stage III ER+/HER 2- breast cancer.

Multigene profiles to guide the use of neoadjuvant chemotherapy for breast cancer: a Copenhagen Breast Cancer Genomics Study

Estrogen receptor (ER) and human epidermal growth factor 2 (HER2) expression guide the use of neoadjuvant chemotherapy (NACT) in patients with early breast cancer. We evaluate the independent predictive value of adding a multigene profile (CIT256 and PAM50) to immunohistochemical (IHC) profile regarding pathological complete response (pCR) and conversion of positive to negative axillary lymph node status. The cohort includes 458 patients who had genomic profiling performed as standard of care. Using logistic regression, higher pCR and node conversion rates among patients with Non-luminal subtypes are shown, and importantly the predictive value is independent of IHC profile. In patients with ER-positive and HER2-negative breast cancer an odds ratio of 9.78 (95% CI 2.60;36.8), P < 0.001 is found for pCR among CIT256 Non-luminal vs. Luminal subtypes. The results suggest a role for integrated use of up-front multigene subtyping for selection of a neoadjuvant approach in ER-positive HER2-negative breast cancer.

Impact of the 21-Gene Assay in Patients with High-Clinical Risk ER-Positive and HER2-Negative Early Breast Cancer: Results of the KARMA Dx Study

BACKGROUND

The 21-gene Oncotype DX Breast Recurrence Score^® assay is prognostic and predictive of chemotherapy benefit for patients with estrogen receptor-positive, HER2- early breast cancer (EBC). The KARMA Dx study evaluated the impact of the Recurrence Score^® results (RS) on the treatment decision for patients with EBC and high-risk clinicopathological characteristics for whom chemotherapy (CT) was considered.

METHODS

Eligible patients with EBC were candidates for the study if CT was considered standard recommendation by local guidelines. Three high-risk EBC cohorts were predefined: (A) pT1-2, pN0/N1mi, and grade 3; (B) pT1-2, pN1, and grades 1-2; and (C) neoadjuvant cT2-3, cN0, and Ki67 ≤ 30%. Treatment recommendations before and after 21-gene testing were registered, as well as treatment received and physicians' confidence levels in their final recommendations.

RESULTS

A total of 219 consecutive patients were included from eight Spanish centers: 30 in cohort A, 158 in cohort B, and 31 in cohort C. Ten patients were excluded from the final analysis as CT was not initially recommended. After 21-gene testing, treatment decisions changed from CT + endocrine therapy (ET) to ET alone for 67% of the whole group. In total, 30% (95% confidence interval [CI] 15% to 49%), 73% (95% CI 65% to 80%), and 76% (95% CI 56% to 90%) of patients ultimately received ET alone in cohorts A, B, and C, respectively. Physicians' confidence in their final recommendations increased in 34% of cases.

CONCLUSIONS

Use of the 21-gene test resulted in an overall 67% reduction in CT recommendation in patients considered candidates for CT. Our findings indicate the substantial potential of the 21-gene test to guide CT recommendations in patients with EBC considered to be at high risk of recurrence based on clinicopathological parameters, regardless of nodal status or treatment setting.

The Impact of Chemotherapy Prescription on Long-Term Survival Outcomes in Early-Stage Invasive Lobular Carcinoma - A Systematic Review and Meta-Analysis

INTRODUCTION

Invasive lobular carcinoma (ILCs) are typically endocrine responsive breast cancers which respond poorly to chemotherapy. The long-term survival advantage of prescribing chemotherapy in such cases remains unclear. To perform a systematic review and meta-analysis assessing, the impact of prescribing chemotherapy in such patients on long-term disease-free (DFS) and overall (OS) survival outcomes.

METHODS

A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. Ten-year DFS and OS were pooled as odds ratios (ORs) with 95% confidence intervals (CI) using the Mantel-Haenszel method. Time-to-effect modelling was performed using the generic inverse variance method.

RESULTS

Overall, 9 studies including 28,218 patients were included. The mean follow-up was 74 months (range: 0-150 months) and mean age was 60 years (range: 22-90 years). Of these, 34.7% received chemotherapy (9,797/28,218) and 66.3% did not receive chemotherapy (18,421/28,218). Chemotherapy prescription failed to improve 10-year DFS (OR: 0.89, 95% CI: 0.65-1.23) and OS (OR: 0.92, 95% CI: 0.72-1.18). When using time-to-effect modelling, chemotherapy prescription failed to improve DFS (hazard ratio (HR): 1.01, 95% CI: 0.78-1.31) and OS (HR: 1.07, 95% CI: 0.89-1.27, I²= 67%).

CONCLUSION

This meta-analysis illustrates no long-term survival advantage associated with chemotherapy prescription in the setting of early-stage ILC. In the absence of well-designed, prospective clinical trials evaluating the impact of chemotherapy on long-term outcomes in ILC, these results should be considered by the multidisciplinary team when deciding on the value of systemic chemotherapy prescription in ILC.

Tailoring neoadjuvant treatment of HR-positive/HER2-negative breast cancers: Which role for gene expression assays?

Neoadjuvant chemotherapy (NACT) for breast cancer (BC) increases surgical and conservative surgery chances. However, a significant proportion of patients will not be eligible for conservative surgery following NACT because of large tumor size and/or low chemosensitivity, especially for hormone receptor (HR)-positive/ human epidermal growth factor receptor 2 (HER2)-negative tumors, for which pathological complete response rates are lower than for other BC subtypes. On the other hand, for luminal BC neoadjuvant endocrine therapy could represent a valid alternative. Several gene expression assays have been introduced into clinical practice in last decades, in order to define prognosis more accurately than clinico-pathological features alone and to predict the benefit of adjuvant treatments. A series of studies have demonstrated the feasibility of using core needle biopsy for gene expression risk testing, finding a high concordance rate in the risk result between biopsy sample and surgical samples. Based on these premises, recent efforts have focused on the utility of gene expression signatures to guide therapeutic decisions even in the neoadjuvant setting. Several prospective and retrospective studies have investigated the correlation between gene expression risk score from core needle biopsy before neoadjuvant therapy and the likelihood of 1) clinical and pathological response to neoadjuvant chemotherapy and endocrine therapy, 2) conservative surgery after neoadjuvant chemotherapy and endocrine therapy, and 3) survival following neoadjuvant chemotherapy and endocrine therapy. The purpose of this review is to provide an overview of the potential clinical utility of the main commercially available gene expression panels (Oncotype DX, MammaPrint, EndoPredict, Prosigna/PAM50 and Breast Cancer Index) in the neoadjuvant setting, in order to better inform decision making for luminal BC beyond the exclusive contribution of clinico-pathological features.

Low correlation between Ki67 assessed by qRT-PCR in Oncotype Dx score and Ki67 assessed by Immunohistochemistry

Breast cancers expressing high levels of Ki67 are associated with poor outcomes. Oncotype DX test was designed for ER+/HER2- early-stage breast cancers to help adjuvant chemotherapy decision by providing a Recurrent Score (RS). RS measures the expression of 21 specific genes from tumor tissue, including Ki67. The primary aim of this study was to assess the agreement between Ki67_RNA obtained with Oncotype DX RS and Ki67_IHC. Other objectives were to analyze the association between the event free survival (EFS) and the expression level of Ki67_RNA; and association between RS and Ki67_RNA. Herein, we report a low agreement of 0.288 by Pearson correlation coefficient test between Ki67_IHC and Ki67_RNA in a cohort of 98 patients with early ER+/HER2- breast cancers. Moreover, Ki67_RNA^high tumors were significantly associated with the occurrence of events (p = 0.03). On the other hand, we did not find any association between Ki67_IHC and EFS (p = 0.26). We observed a low agreement between expression level of Ki67_RNA and Ki67 protein labelling by IHC. Unlike Ki67_IHC and independently of the RS, Ki67_RNA could have a prognostic value. It would be interesting to better assess the prognosis and predictive value of Ki67_RNA measured by qRT-PCR. The Ki67_RNA in medical routine could be a good support in countries where Oncotype DX is not accessible.

Gene-expression signatures to inform neoadjuvant treatment decision in HR+/HER2- breast cancer: Available evidence and clinical implications

Over the last few years, the indication for chemotherapy use in HR+/HER2- early BC has been significantly modified by the introduction of gene-expression profiling. In the adjuvant setting, several gene-expression signatures have been validated to discriminate early stage HR+/HER2- BC with different prognosis and to identify patients for which adjuvant chemotherapy can be spared. Considering their ability to optimize the choice of adjuvant treatment and the increasing use of neoadjuvant approach in early BC, the potential use of gene-expression signatures to discriminate patients to be candidate to neoadjuvant chemotherapy or endocrine treatment appears particularly appealing. Indeed, the San Gallen Consensus Conference panel recently endorsed the use of genomic assays on core biopsies as a potential strategy for choosing the type of neoadjuvant treatment (chemotherapy or endocrine therapy) in selected patients. In this context, we here review evidence supporting the use of most common commercially available gene-expression signatures (Oncotype DX, MammaPrint, PAM50, EndoPredict and Breast Cancer Index) in patients receiving neoadjuvant therapy for HR+/HER2- BC. Data on the association of gene expression signatures and response to neoadjuvant chemotherapy or neoadjuvant endocrine therapy will be reviewed and the clinical implications of this data to guide the clinical decision-making process in early HR+/HER2- BC will be discussed.

Advancement of prognostic models in breast cancer: a narrative review

Objective

To provide a reference for clinical work and guide the decision-making of healthcare providers and end-users, we systematically reviewed the development, validation and classification of classical prognostic models for breast cancer.

Background

Patients suffering from breast cancer have different prognosis for its high heterogeneity. Accurate prognosis prediction and risk stratification for breast cancer are crucial for individualized treatment. There is a lack of systematic summary of breast cancer prognostic models.

Methods

We conducted a PubMed search with keywords "breast neoplasm", "prognostic model", "recurrence" and "metastasis", and screened the retrieved publications at three levels: title, abstract and full text. We identified the articles presented the development and/or validation of models based on clinicopathological factors, genomics, and machine learning (ML) methods to predict survival and/or benefits of adjuvant therapy in female breast cancer patients.

Conclusions

Combining prognostic-related variables with long-term clinical outcomes, researchers have developed a series of prognostic models based on clinicopathological parameters, genomic assays, and medical figures. The discrimination, calibration, overall performance, and clinical usefulness were validated by internal and/or external verifications. Clinicopathological models integrated the clinical parameters, including tumor size, histological grade, lymph node status, hormone receptor status to provide prognostic information for patients and doctors. Gene-expression assays deeply revealed the molecular heterogeneity of breast cancer, some of which have been cited by AJCC and National Comprehensive Cancer Network (NCCN) guidelines. In addition, the models based on the ML methods provided more detailed information for prognosis prediction by increasing the data dimension. Combined models incorporating clinical variables and genomics information are still required to be developed as the focus of further researches.

Value of a 21-gene expression assay on core biopsy to predict neoadjuvant chemotherapy response in breast cancer: systematic review and meta-analysis

BACKGROUND

A recurrence score based on a 21-gene expression assay predicts the benefit of adjuvant chemotherapy in oestrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer. This systematic review aimed to determine whether the 21-gene expression assay performed on core biopsy at diagnosis predicted pathological complete response (pCR) to neoadjuvant chemotherapy.

METHODS

The study was performed according to PRISMA guidelines. Relevant databases were searched to identify studies assessing the value of the 21-gene expression assay recurrence score in predicting response to neoadjuvant chemotherapy in patients with breast cancer. The Newcastle-Ottawa Scale was used to assess the quality of the studies. Results are reported as risk ratio (RR) with 95 per cent confidence interval using the Cochrane-Mantel-Haenszel method for meta-analysis. Sensitivity analyses were carried out where appropriate.

RESULTS

Seven studies involving 1744 patients reported the correlation between pretreatment recurrence score and pCR. Of these, 777 patients (44.6 per cent) had a high recurrence score and 967 (55.4 per cent) a low-intermediate score. A pCR was achieved in 94 patients (5.4 per cent). The pCR rate was significantly higher in the group with a high recurrence score than in the group with a low-intermediate score (10.9 versus 1.1 per cent; RR 4.47, 95 per cent c.i. 2.76 to 7.21; P < 0.001). A significant risk difference was observed between the two groups (risk difference 0.10, 0.04 to 0.15; P = 0.001).

CONCLUSION

A high recurrence score is associated with higher pCR rates and a low-intermediate recurrence score may indicate chemoresistance. Routine assessment of recurrence score by the 21-gene expression assay on core biopsy might be of value when considering neoadjuvant chemotherapy in patients with ER-positive, HER2-negative breast cancer.

Selection of neoadjuvant treatment based on the 21-GENE test results in luminal breast cancer

Neoadjuvant chemotherapy (NAC) is an optimal option in early breast cancer, but in ER-positive/HER2-negative (luminal) is still controversial, although a survival benefit has recently been observed when a histological response by Symmans’ method type 0 or I is achieved. The 21-gene Oncotype DX Breast Recurrence Score® assay (Oncotype DX®) is a validated test to assess the survival benefit of adjuvant chemotherapy in these patients but its role in the neoadjuvant setting is less established. We analyzed the results of the Oncotype DX® test in a cohort of 122 consecutive patients selected to receive NAC based on classical clinicopathological parameters and the correlation between the Oncotype DX® results and the pathological response assessed by Symmans’ method. Median age was 56.5 (range 31–84) years. Initial tumor size was T1 (<20 mm) in 46 patients (37.7%), 57 (46.7%) had a T2 tumor (20–50 mm), and 19 (15.6%) had a tumor size more than 50 mm. 59 (48.4%) had axillary node involvement. The median expression estrogen and progesteron receptors by immunohistochemistry was 280 and 120 respectively and median Ki67 index was 28%. The Recurrence Score (RS) results were <11 in 21 patients (17.2%) patients, RS 11 to 25 in 58 (47.5%), and RS > 25 in 43 (35.2%). Considering the Oncotype DX test results, neoadjuvant chemotherapy was administered to 60 patients (49%), 11 (9%) received adjuvant chemotherapy and 51 (42%) no chemotherapy. Testing with the assay has therefore led to 42% fewer chemotherapy treatments. Among 60 patients receiving NAC, pathologic response was achieved for 5 patients (8.3%) with RCB-0 and 15 RCB-1 (25%). We did not find any pathological response RCB-0 and RCB-I in the 20 patients who received NAC and had a Recurrence Score result <21 for the premenopausal group, or a RS result <25 for the postmenopausal group. For patients with highest Recurrence Score results (RS > 21 or 25 according to menopausal status) it was 12% (5/40) RCB-0 and 40% (16/40) RCB-I.

Conclusions

The Oncotype DX test could be a useful tool to select patients candidates for neoadjuvant chemotherapy in luminal breast cancer. Neoadjuvant chemotherapy could be avoided in 42% of patients. We found a correlation between Recurrence Score results and pathological response with 14% of RCB-0 and a total of 47% of significant pathological response type RCB-0 and RCB-I in patients with highest Recurrence Score results. Interestingly, patients with a Recurrence Score result inferior to 32 did not get any histological response type 0 and only 5% RCB-I.

•

All comments are reviewed in the main manuscript text.

•

We have introduced changes in tables and Figures according Editor′s comments.

•

It is an academic study and we don′t received any founding and we appreciate all patients who participated.

Response to neoadjuvant chemotherapy and the 21-gene Breast Recurrence Score test in young women with estrogen receptor-positive early breast cancer

PURPOSE

The 21-gene Breast Recurrence Score test predicts benefit from adjuvant chemotherapy in estrogen receptor-positive, HER2-negative (ER+/HER2-) breast cancer (BC). We examined whether the 21-gene assay predicts response to neoadjuvant chemotherapy (NCT).

METHODS

We identified patients with stage I-III ER+/HER2- BC treated with NCT from the Young Women's Breast Cancer Study, a prospective cohort of women diagnosed with BC at age ≤40 years. The 21-gene assay was performed on tumor specimens removed prior to NCT either as part of clinical care or retrospectively for research. Pathological complete response (pCR) was defined as ypT0/is ypN0. The relationship between Recurrence Score result and pCR was evaluated using logistic regression modeling.

RESULTS

76 women received NCT for ER+/HER2- BC and were eligible for this analysis. Median age at diagnosis was 37 years (range 24-40). Scores ranged between 5 and 77 with 50% >25 and 5% <11. Median Recurrence Score result was significantly higher among tumors achieving pCR vs. non-pCR response (61.5 vs. 23, p_wilcoxon = 0.0005). pCR rate in patients with scores >25 was 21% (8/38) vs. 5% in patients with scores <25 (2/38) (p = 0.09), with both pCRs in the <25 group in patients with scores between 21 and 25. In multivariable analysis, only Recurrence Score result was significantly associated with pCR (OR: 1.07, 95%CI 1.01-1.12, p = 0.01).

CONCLUSIONS

In young women with ER+/HER2- BC who received NCT, higher pretreatment Recurrence Score result was associated with an increased likelihood of pCR. Gene expression profile assays may have a role in decision making in young women in need of neoadjuvant therapy.

Molecular characterization of breast cancer needle core biopsy specimens by the 21-gene Breast Recurrence Score test

BACKGROUND AND OBJECTIVE

Recent COVID-19 pandemic guidelines recommend genomic assessment of core biopsies to help guide treatment decisions in estrogen receptor (ER)-positive early-stage breast cancer. Herein we characterize biopsy and excisional breast cancer specimens submitted for 21-gene testing.

METHODS

US samples submitted to Genomic Health for 21-gene testing (01/2004-04/2020) were assessed by pathologists and analyzed by a standardized quantitative reverse transcription-polymerase chain reaction. Predefined cutoffs were: ESR1 (positive ≥6.5), PGR (positive ≥5.5), and ERBB2 (negative <10.7). ER status by immunohistochemistry (IHC) and lymph node status were determined locally. Median and interquartile range were reported for continuous variables, and total and percent for categorical variables. Distributions were assessed overall, by age, and by nodal involvement.

RESULTS

Of 919 701 samples analyzed, 13% were biopsies and 87% were excisions. Initial assay success rates were 94.5% (biopsies) and 97.3% (excisions). ER IHC concordance with central ESR1 was 96.8% (biopsies) and 97.6% (excisions). Biopsy and excisional medians were: Recurrence Score results 16 (each); ESR1 10.2 (each); PGR 7.7 and 7.6; ERBB2 9.4 and 9.2, respectively.

CONCLUSIONS

Biopsy submissions for 21-gene testing are common and consistently generate results that are very similar to the experience with excisions. The 21-gene test can be performed reliably on core biopsies.

The Correlation of Magee EquationsTM and Oncotype DX® Recurrence Score From Core Needle Biopsy Tissues in Predicting Response to Neoadjuvant Chemotherapy in ER+ and HER2- Breast Cancer

Objective

Oncotype DX^® recurrence score (RS) can be predicted from Magee Equations^TM (MS) postoperatively. The aim of this study is to investigate correlation of MS with RS from pretreatment core needle biopsy (CNB) tissues, and their clinical usefulness in prediction of response to neoadjuvant chemotherapy (NCT) in estrogen receptor-positive and human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer (BC).

Materials and Methods

Pretreatment CNB tissue samples from 60 patients with ER+/HER2- invasive BC were analyzed for MS and RS correlation. MS and RS were categorized as follows: low (<18), intermediate (18-30), and high (≥ 31). Percentage Tumor size Reduction (%TR) was used to assess tumor response to NCT, and substantial %TR was defined as at least 50% reduction (≥50%TR). Correlation between MS and RS, and predictive factors for the ≥50%TR achievement were assessed.

Results

MS and RS represented a strong correlation (Spearman's correlation; r=0.58, p<0.0001) as a continuous variable. As a categorical variable, the concordance between MS and RS was 43.3%, and it increased to 80% (r=0.61, p=0.003) with the exclusion of the intermediate risk categories. Although, there was pathologic complete response (pCR), MS showed the highest predictive power for the ≥50% TR achievement, none of the factors were statistically significant (p≥0.07).

Conclusion

Our study demonstrated that there was a strong correlation between MS and RS from pretreatment biopsy tissue samples in ER+ and HER2- invasive BC.

Validation of the 21-gene test as a predictor of clinical response to neoadjuvant hormonal therapy for ER+, HER2-negative breast cancer: the TransNEOS study

Purpose

The Recurrence Score test is validated to predict benefit of adjuvant chemotherapy. TransNEOS, a translational study of New Primary Endocrine-therapy Origination Study (NEOS), evaluated whether Recurrence Score results can predict clinical response to neoadjuvant letrozole.

Methods

NEOS is a phase 3 clinical trial of hormonal therapy ± adjuvant chemotherapy for postmenopausal patients with ER+, HER2-negative, clinically node-negative breast cancer, after six months of neoadjuvant letrozole and breast surgery. TransNEOS patients had tumors ≥ 2 cm and archived core-biopsy samples taken before neoadjuvant letrozole and subsequently sent for Recurrence Score testing. The primary endpoint was to evaluate clinical (complete or partial) response to neoadjuvant letrozole for RS < 18 versus RS ≥ 31. Secondary endpoints included evaluation of clinical response and rate of breast-conserving surgery (BCS) by continuous Recurrence Score result, ESR1 and PGR single-gene scores, and ER gene-group score.

Results

Of 295 TransNEOS patients (median age 63 years; median tumor size 25 mm; 66% grade 1), 53.2% had RS < 18, 28.5% had RS18–30, and 18.3% had RS ≥ 31. Clinical response rates were 54% (RS < 18), 42% (RS18–30), and 22% (RS ≥ 31). A higher proportion of patients with RS < 18 had clinical responses (p < 0.001 vs. RS ≥ 31). In multivariable analyses, continuous Recurrence Score result (p < 0.001), ESR1 score (p = 0.049), PGR score (p < 0.001), and ER gene-group score (p < 0.001) were associated with clinical response. Recurrence Score group was significantly associated with rate of BCS after neoadjuvant treatment (RS < 18 vs. RS ≥ 31, p = 0.010).

Conclusion

The Recurrence Score test is validated to predict clinical response to neoadjuvant letrozole in postmenopausal patients with ER+, HER2-negative, clinically node-negative breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4964-y) contains supplementary material, which is available to authorized users.

Breast cancer histopathology is predictive of low-risk Oncotype Dx recurrence score

BACKGROUND

Oncotype Dx is a genetic test that has been incorporated into the 2017 AJCC breast cancer staging system for ER positive, HER2-negative, lymph node-negative patients to predict the risk of recurrence. Recent data suggest that immunohistochemistry (ER, PR, HER2, and Ki-67) and histologic subtype may identify patients that will not benefit from Oncotype Dx testing.

METHODS

A total of 371 patients underwent Oncotype Dx testing at our institution from 2012 to 2016. Oncotype recurrence score was categorized as low- (ORS = 0-10), intermediate- (11-25), or high risk (26-100). Invasive carcinomas were categorized based on histologic subtype as "favorable" (mucinous, tubular, cribriform, tubulolobular, and lobular) and "unfavorable" (ductal, mixed ductal and lobular, and micropapillary carcinoma). All cases were estrogen receptor positive and HER2-negative. Clinical and histologic predictors of low-risk ORS were assessed in univariate and multivariate logistic regression.

RESULTS

A total of 371 patients were categorized by ORS as low risk (n = 85, 22.9%), intermediate risk (n = 244, 65.8%), and high risk (n = 42, 11.3%). The histologic subtypes with the highest percentage of high-risk ORS were invasive micropapillary (n = 4/17, 23.5%), pleomorphic lobular (n = 2/10, 20%), and ductal carcinoma (n = 28/235, 11.9%). Low-grade invasive carcinomas with favorable histology rarely had a high-risk ORS (n = 1/97, 1%). In a simple multivariable model, favorable histologic subtype (OR = 2.39, 95% CI: 1.10 to 5.15, P = 0.026), and histologic grade (OR = 1.76, 95% CI: 1.07 to 2.90, P = 0.025) were the only significant predictors of an ORS less than 11 in estrogen receptor positive, HER2-negative, and lymph node-negative patients.

CONCLUSION

We question the utility of performing Oncotype Dx in subtypes of invasive carcinoma that are associated with excellent prognosis. We propose that immunohistochemistry for ER, PR, and HER2 is sufficient for patients with low-grade invasive carcinomas and can be used as a surrogate for Oncotype Dx.