The 13th St Gallen International Breast Cancer Conference Expert Panel, for the second time, recognized the Oncotype DX breast cancer assay for its ability to provide not only prognostic, but also predictive information regarding the utility of cytotoxic therapy in addition to endocrine therapy for patients with node-negative or node-positive early stage invasive breast cancer. The Panel considered that only the 21-gene RS was predictive of chemotherapy responsiveness, though a substantial minority would also endorse PAM50 or the 70-gene signature for this purpose. This led to a recommendation that selection of patients who might forego chemotherapy could be based on the 21-gene RS, but the Panel did not offer majority endorsement for PAM50, the 70-gene signature or EPClin as yet established for this purpose
European Society of Medical Oncology (ESMO)
Gene expression profiles such as Oncotype DX Recurrence Score® result (Genomic Health, Redwood City, USA) may be used to gain additional prognostic and/or predictive information to complement pathology assessment and to predict response to adjuvant chemotherapy.
"On retrospective analysis of two trials (NSABP B-14 and B-20) performed in women with hormone receptor-positive, axillary lymph node-negative invasive breast cancer, this assay system was able to quantify risk of recurrence as a continuous variable (eg, Oncotype DX Recurrence Score) and to predict responsiveness to both tamoxifen and CMF or methotrexate/5-fluorouracil/leucovorin chemotherapy."
The Oncotype DX assay may be used in newly diagnosed ER+, N- invasive breast cancer patients to predict risk of recurrence. The assay can also be used to identify patients who may be successfully treated with tamoxifen and may not require adjuvant chemotherapy. "It has been suggested that tamoxifen-treated patients with an excellent estimated prognosis may be spared adjuvant chemotherapy." Access these .
The UK's National Institute for Health and Care Excellence (NICE) recommended the Oncotype DX assay for use in clinical practice to guide adjuvant chemotherapy treatment decisions for certain patients with early-stage breast cancer, including micrometastatic disease. .
Insight Beyond Traditional Markers
The Oncotype DX Recurrence Score results provide additional insight into underlying tumour biology beyond traditional measures such as patient age, tumour size, tumour grade, Ki-67, and ER status 1-10
Patient age and tumour size cannot predict the Recurrence Score result
Tumour size cannot predict Recurrence Score result
Prospective analysis of archived tissue from 651 patients with ER-positive, node-negative invasive breast cancer treated with tamoxifen or tamoxifen plus CMF/MF. Approximately 45% of the patients were <50 years of age, two-thirds of tumours were ≤2.0 cm in size, and 20% of tumours were PR-negative.
Tumour grade cannot predict the Recurrence Score result
The Oncotype DX assay reveals critical information that changes treatment decisions.1
Because high and low Oncotype DX Recurrence Score results reflect different intrinsic tumour biology, physicians can make decisions based on underlying disease.
Combinations of patient age, grade, and tumour size cannot predict the Recurrence Score result1
Study included 1,864 ER-positive, HER2-negative, node-negative patients from the Clalit and Maccabi Health Services in Israel.
Oncotype DX provides an individualised Recurrence Score result that cannot be predicted by traditional clinicopathologic variables alone or in combination.1
Ki-67 cannot predict predict the Recurrence Score result6
- There is a wide range of Recurrence Score results for varying Ki-67 cutoffs. There is only moderate correlation between the Recurrence Score result and Ki-67 (rs = 0.374; p<0.001)6,7
- The Recurrence Score result cannot be predicted by Ki-67
- Currently the clinical utility of Ki-67 in early-stage invasive breast cancer is limited due to lack of analytic reproducibility and standardization8
Quantitative RT-PCR provides insight beyond traditional measures9,10
Study included 100,000 invasive breast cancer tumour specimens that were examined in the Genomic Health laboratory from July 2005 through May 2009. Quantitative expression for each gene was measured by the Oncotype DX assay on a scale from 0 to 15, relative to reference genes.
- Quantitative RT-PCR is able to identify a continuum of gene expression10
- Three groups are discernible: HER2-positive, ER-positive/HER2-negative, and a triple-negative group10
- Within each group is a wide distribution of expression and heterogeneity that might not be detected by binary methods
In a multivariate analysis of clinicopathologic measures from NSABP B-20, the Oncotype DX Recurrence Score result was the strongest predictor of chemotherapy benefit in node-negative patients1