How Canadian Oncologists Use Oncotype DX for Treatment of Breast Cancer Patients

Is Oncotype DX testing informative for breast cancers with low ER expression? A retrospective review from a biomarker testing referral center

PURPOSE

It remains unclear whether patients with HER2-negative, low-estrogen receptor (ER-low)-positive early breast cancer (BC) benefit from Oncotype DX® (ODX) testing.

METHODS

We conducted a retrospective review of cases referred for ODX testing over a seven-year period from a breast biomarker testing referral center (n = 854). For each case, we recorded the ODX Recurrence Score (RS) along with percentage of ER nuclear positivity and staining intensity on immunohistochemistry. Our criteria for ER-low was defined as ≤10% cells with nuclear positivity and/or weak intensity of staining. Slides from all ER-low cases were reviewed and the reported ODX ER gene scores were recorded. We randomly selected a comparator group of 56 patients with ER > 10% positivity and non-weak staining intensity (ER-high).

RESULTS

We identified 27 cases (3.2%) that met our criteria for ER-low. Of these, 92.6% had a high RS (>25), and 7.4% had a RS of 25. All cases with ≤10% ER nuclear positivity had a high RS. Most ER-low cases (85.2%) had ODX quantitative ER gene scores in the negative range, whereas all (100%) ER-high cases had positive ER gene scores.

CONCLUSION

ODX does not appear to add significant additional information to inform treatment decisions for most patients with ER-low BC. Incorporating weak ER staining intensity in addition to low percentage of nuclear positivity identifies about twice as many ER-low patients, although with reduced specificity for high RS. Our study supports the contention that most ER-low early BC should be regarded similarly to ER-negative BC.

Oncotype DX in Breast Cancer Management: Insights and Outcomes From the United Arab Emirates

Introduction Breast cancer remains the most significant cancer affecting women worldwide, with an increasing incidence, especially in developing regions. The introduction of genomic tests like Oncotype DX has revolutionized personalized treatment, allowing for more tailored approaches to therapy. This study focuses on the United Arab Emirates (UAE), where breast cancer is the leading cause of cancer-related deaths among women, aiming to assess the predictive accuracy of the Oncotype DX test in categorizing patients based on recurrence risk. Materials and methods A retrospective cohort study was conducted on 95 breast cancer patients diagnosed at Tawam Hospital between 2013 and 2017 who underwent Oncotype DX testing. Data on patient demographics, tumor characteristics, treatment details, and Oncotype DX scores were collected. Survival analysis was performed using the Kaplan-Meier method, with the chi-square goodness of fit test assessing the model's adequacy. Results The cohort's age range was 27-71 years, with a mean age of 50, indicating a significant concentration of cases in the early post-menopausal period. The Oncotype DX analysis classified 55 patients (57.9%) as low risk, 29 (30.5%) as medium risk, and 11 (11.6%) as high risk of recurrence. The majority, 73 patients (76.8%), did not receive chemotherapy, highlighting the test's impact on treatment decisions. The survival analysis revealed no statistically significant difference in recurrence rates across the Oncotype DX risk categories (p = 0.268231). Conclusion The Oncotype DX test provides a valuable genomic approach to categorizing breast cancer patients by recurrence risk in the UAE. While the test influences treatment decisions, particularly the use of chemotherapy, this study did not find a significant correlation between Oncotype DX risk categories and actual recurrence events. These findings underscore the need for further research to optimize the use of genomic testing in the UAE's diverse patient population and enhance personalized treatment strategies in breast cancer management.

Impact of the 21-gene expression assay on treatment decisions and clinical outcomes in breast cancer with one to three positive lymph nodes

BACKGROUND

To assess the practice patterns of the recurrence score (RS) based on the 21-gene expression assay on adjuvant chemotherapy recommendations and survival outcomes in estrogen receptor-positive (ER+)/HER2- breast cancer (BC) with one to three positive lymph nodes (N1).

METHODS

We included patients with T1-2N1M0 and ER+/HER2- BC diagnosed between 2010 and 2015 in the Surveillance, Epidemiology, and End Results Oncotype DX Database. Breast cancer-specific survival (BCSS) and overall survival (OS) were assessed.

RESULTS

We included 35,137 patients in this study. There were 21.2% of patients who had RS testing in 2010, which was significantly increased to 36.8% in 2015 (P < 0.001). Performance of the 21-gene testing was associated with older age, lower tumor grade, T1 stage, lower number of positive lymph nodes, and progesterone receptor-positive disease (all P < 0.05). In those without 21-gene testing, age was the main factor significantly related to the receipt of chemotherapy, whereas RS was the main factor significantly related to chemotherapy receipt in those with 21-gene testing. The probability of chemotherapy receipt in those without 21-gene testing was 64.1% and was decreased to 30.8% in those with 21-gene testing. On multivariate prognostic analysis, the performance of 21-gene testing was associated with better BCSS (P < 0.001) and OS (P < 0.001) compared with those without 21-gene testing. Similar results were found after propensity score matching.

CONCLUSIONS

The 21-gene expression assay is frequently and increasingly used for chemotherapy decision-making in ER+/HER2- BC with N1 disease. Performance of the 21-gene testing is associated with improved survival outcomes. Our study supports the routine use of 21-gene testing in the clinical practice of this population.

The Role of the 21-Gene Recurrence Score® Assay in Hormone Receptor-Positive, Node-Positive Breast Cancer: The Canadian Experience

The management of patients with hormone receptor-positive breast cancer has changed dramatically with use of the 21-gene Recurrence Score® (RS) Assay. While the utility of the assay was initially demonstrated among node-negative patients, recent studies have also demonstrated the assay's prognostic and predictive value in node-positive patients. In Canada, the RS assay is reimbursed by provincial health insurance plans, but not all provinces have approved the use of the assay for patients with node-positive disease. Here, we provide an overview of the clinical factors that influence physician recommendation of the RS assay and, alternatively, the impact of the RS assay on patient treatment decisions in Canada. We performed a comprehensive review of the impact of the assay upon physician treatment decisions and cost in node-positive breast cancer patients within Canada and other countries. Furthermore, we evaluated biomarkers that can predict the RS result, in addition to other genomic assays that predict recurrence risk among node-positive patients. Overall, the 21-gene RS assay was shown to be a cost-effective tool that significantly reduced the use of chemotherapy in node-positive breast cancer patients in Canada.

Identifying Clinicopathological Factors Associated with Oncotype DX® 21-Gene Recurrence Score: A Real-World Retrospective Cohort Study of Breast Cancer Patients in Quebec City, Canada

Gene expression profiling tests such as the Oncotype DX (ODX) 21-gene recurrence score (RS) assay is increasingly used in clinical practice to predict the risk of recurrence and support treatment planning for early-stage breast cancer (BC). However, this test has some disadvantages such as a high cost and a long turnaround time to get results, which may lead to disparities in access. We aim to identify clinicopathological factors associated with ODX RS in women with early-stage BC. We conducted a retrospective cohort study of women identified in the medical database of the Deschênes-Fabia Breast Disease Center of Quebec City University, Canada. Our sample consists of 425 women diagnosed with early-stage BC who have obtained an ODX RS between January 2011 and April 2015. The ODX RS has been categorized into three levels as originally defined: low (0-17), intermediate (18-30), and high (>30). The mean RS was 17.8 (SD = 9.2). Univariate analyses and multinomial logistic regressions were performed to identify factors associated with intermediate and high RS compared with low RS. A total of 237 (55.8%) patients had low RS, 148 (34.8%) had intermediate RS, and 40 (9.4%) had high RS. Women with progesterone receptor (PR)-negative (ORs ranging from 3.51 to 10.34) and histologic grade II (ORs ranging from 3.16 to 23.04) tumors were consistently more likely to have intermediate or high RS than low RS. Similar patterns of associations were observed when the RS was categorised using redefined thresholds from (i.e., from the TAILORx study or dichotomized). This study provides evidence suggesting that histologic grade and PR status are predictive factors for intermediate or high RS in women with early-stage BC. If these results are confirmed in future studies, considering these clinicopathological factors could spare women the need to get such a test before the beginning of a possible adjuvant therapy. This option could be considered in settings where the cost of testing is an issue.