The EndoPredict test is a prognostic tool for individuals with early-stage breast cancer. It analyzes tumor characteristics to forecast the likelihood of the cancer returning in a distant part of the body, a process known as distant recurrence. This information assists patients and doctors in making informed decisions about treatment after surgery. The test is designed to provide a clearer picture of the individual nature of a tumor.
Who Is a Candidate for the EndoPredict Test?
The EndoPredict test is not for every person with breast cancer; its use is specific to a particular subtype. Candidates have early-stage breast cancer that is estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2-negative (HER2-). ER+ means the cancer cells use the hormone estrogen to grow. HER2- indicates that the cancer cells do not have an excess of the HER2 protein, which can promote cancer cell growth.
This test can be applied to patients regardless of whether the cancer has spread to nearby lymph nodes. It is validated for use in individuals with node-negative cancer, where no cancer cells are found in the lymph nodes. It is also appropriate for patients with up to three positive lymph nodes, meaning cancer has been detected in a small number of nodes.
How the EndoPredict Score Is Determined
The final EndoPredict score integrates both molecular and clinical information. The process uses a small sample of the tumor tissue collected during a biopsy or surgery. This tissue is sent to a laboratory where the molecular score (or EP score) is determined by analyzing the activity level of 12 specific genes within the cancer cells.
These 12 genes are selected for their roles in processes like cell proliferation and their connection to the estrogen receptor pathway. Eight of these are cancer-related genes, three are reference genes used for normalization, and one is a control gene. The expression levels of these genes are measured and fed into a mathematical algorithm to produce the molecular score.
This molecular score is then combined with two established clinical factors: the size of the tumor and the nodal status, which is whether cancer cells are present in the lymph nodes. This combination creates the comprehensive EPclin Risk Score. The integration of the tumor’s biological activity with its anatomical extent provides a more complete assessment of its potential behavior.
Understanding Your EndoPredict Results
The result of the EndoPredict test is an EPclin Risk Score, which places a patient’s cancer into a “low risk” or “high risk” category. This classification forecasts the chance of distant recurrence within 10 years after diagnosis. This prediction assumes the patient will be completing at least five years of standard endocrine therapy.
A “low-risk” result indicates a less than 10% chance of distant recurrence at 10 years with endocrine therapy alone. For these individuals, the cancer is considered to have a more favorable prognosis and is less likely to spread.
A “high-risk” result signifies a 10% or greater chance of distant recurrence at the 10-year mark, even with endocrine therapy. This suggests the cancer has more aggressive biological features. The score gives a personalized percentage, offering a more individualized risk assessment for the patient to consider.
How Results Guide Chemotherapy Decisions
The EndoPredict score has a direct application in planning treatment after surgery. The primary goal is to determine who is most likely to benefit from the addition of chemotherapy to their treatment regimen. The results help to tailor the therapy to the individual.
For patients who receive a “low-risk” score, the results suggest that the cancer is less aggressive. In these cases, the benefit from chemotherapy is expected to be minimal. Therefore, these individuals may be able to forgo chemotherapy and proceed with endocrine therapy as their primary systemic treatment, sparing them from the side effects of chemotherapy.
A “high-risk” classification points to a more aggressive cancer with a greater likelihood of returning. For these patients, the test indicates that adding chemotherapy to endocrine therapy would provide a benefit in reducing the risk of recurrence. This allows doctors to recommend chemotherapy to combat the specific biology of the tumor.
EndoPredict vs. Other Genomic Assays
EndoPredict is one of several genomic tests for early-stage breast cancer, including Oncotype DX and MammaPrint. A notable feature of EndoPredict is its integration of clinical factors—tumor size and nodal status—directly into the final EPclin score alongside the molecular data.
This combined approach differs from some tests that rely solely on gene expression analysis. Another distinction is that EndoPredict provides a definitive low-risk or high-risk result. It does not include an intermediate-risk category, which can give a clearer direction for treatment decisions.
EndoPredict was also developed to predict both early (within the first five years) and late (between 5 and 15 years) distant recurrences. This ability to forecast risk over a longer period can help inform decisions about extending endocrine therapy. The choice between these assays depends on a patient’s diagnosis and a physician’s judgment.