What is the Oncotype DX® assay?
Healthcare Professional Overview
The Oncotype DX Colon Cancer Assay is a 12-gene assay that provides an individualized score reflective of the risk of colon cancer recurrence for individual patients with stage II colon cancer. This quantitative information about recurrence risk, based on the biology of a patient’s specific colon cancer tumor, may help to inform individualized adjuvant treatment decisions in patients with stage II colon cancer. The availability of the Oncotype DX Colon Cancer Assay represents the second successful application of Genomic Health’s unique technology.
Addressing an Unmet Need in the Treatment of Colon Cancer
Colon cancer is the third most prevalent cancer in both men and women in the USA and is the third most common cause of cancer-related deaths. Approximately 30% of patients with colon cancer present with stage II disease. Current NCCN Guidelines do not recommend the routine use of adjuvant chemotherapy for all patients with stage II colon cancer but to consider adjuvant treatment in the setting of high recurrence risk. The five-year survival rate for the overall stage II patient population has been estimated to be 75-80%. Despite these relatively high cure rates with surgery alone, a significant proportion of stage II patients will recur, and considerable effort has been made to identify markers of risk to distinguish those patients at low risk from those at higher risk of colon cancer recurrence, who would be candidates for adjuvant chemotherapy for colon cancer.
Unlike in breast cancer, where molecular markers such as ER, PR, and HER2 have been in long-standing clinical use, markers in stage II colon cancer have been limited to clinical and pathologic parameters. The presence of any of the following features places a patient into a “high risk” category while a patient without these features would be considered “standard risk”:
- T4 lesions
- Fewer than 12 lymph nodes examined
- Presence of bowel perforation or obstruction
- Poorly differentiated tumors,
- Lymphatic or venous invasion
These parameters are generally qualitative and are not informative for further differentiating risk in standard risk colon cancer patients, who constitute the majority of stage II colon cancer. The Oncotype DX Colon Cancer Assay was developed to address this need for new markers to better assess a patient’s risk of recurrence and to individualize treatment decisions for patients with stage II colon cancer.
The Oncotype DX Colon Cancer Assay:
The Oncotype DX Colon Cancer Assay is a standardized multi-gene RT-PCR assay conducted on paraffin-embedded primary colon tumor tissue. This test is performed by Genomic Health in its CLIA-certified, CAP-accredited reference laboratory.
The Oncotype DX Colon Cancer Assay was developed by evaluating 761 colon cancer-related genes in 1,851 patients with resected colon cancer in four large development studies. These development studies led to the definition of the 12-gene panel, including 7 cancer-related genes and 5 reference genes, as well as the Recurrence Score algorithm, which was then prospectively validated in the QUASAR validation study.
The Oncotype DX Colon Cancer Assay uses Genomic Health’s well-established RT-PCR platform to quantitate, in each patient’s colon cancer tumor sample, the level of expression of each of the 12 genes in the panel. For each patient, the test produces a Recurrence Score which predicts the risk of recurrence for that individual patient with Stage II colon cancer. A better understanding of individual recurrence risk of recurrence may serve as an important factor guiding personalized treatment decisions for patients with Stage II colon cancer.
Through the development of the Oncotype DX Colon Cancer Assay, Genomic Health, as a leader in the field of genomics in cancer, is providing a much-needed resource for patients with colon cancer and the physicians who care for them.
The Oncotype Colon Cancer Assay:
- Supports your colon cancer treatment decisions—The only proven, multi-gene expression assay available in colon cancer
- Informs colon cancer treatment decisions and improves confidence for physicians and patients
Colon Cancer Recurrence Score® Result
Because colon cancer is a heterogeneous disease, it is important to have an assay that provides an individualized view of the biology. The Oncotype DX Colon Cancer Assay harnesses the genomic information in each patient’s colon tumor to yield the Recurrence Score, which has been validated as an independent, quantitative predictor of individual colon cancer recurrence risk that provides value beyond existing measures.
- In the validation study the primary analysis of association of continuous Recurrence Score with recurrence in stage II colon cancer patients following surgery was highly significant (p=0.004). The solid blue curve depicts the relationship of continuous Recurrence Score to 3 year recurrence risk, demonstrating a near linear relationship with higher RS associated with higher colon cancer recurrence risk.
- The continuous RS provides quantitative information for an individual patient that has independent value beyond existing clinical and pathological measures. The quantitative individualized recurrence risk provided by the Oncotype DX Colon Cancer Assay can be incorporated with the other clinical features of each patient to develop a treatment plan that is most appropriate for the individual colon cancer patient.
Deciding if Your Colon Cancer Patient Should Be Tested
The Oncotype DX Colon Cancer Assay provides clinical information for women and men with stage II colon cancer. Data to support use of the assay in other stages of colon cancer or in tumor types originating outside the colon are not currently available.
Colon cancer is the third most prevalent cancer in both men and women in the USA and is the third most common cause of cancer related deaths. Approximately 30% of patients present with stage II colon cancer.
Current NCCN Guidelines do not recommend the routine use of adjuvant chemotherapy for all patients with stage II colon cancer but to consider adjuvant treatment in the setting of high recurrence risk. The five-year survival rate for the overall stage II patient population has been estimated to be 75-80%. Despite these relatively high cure rates with surgery alone, a significant proportion of stage II patients will recur, and considerable effort has been made to identify markers of risk to distinguish those colon cancer patients at low risk from those at greatest risk of disease recurrence, who would be candidates for adjuvant chemotherapy colon cancer treatment.
Unlike in breast cancer, where molecular markers such as ER, PR, and HER2 have been in long-standing clinical use, markers in stage II colon cancer have been limited to clinical and pathologic parameters. The presence of any of the following features places a patient into a “high risk” category while a patient without these features would be considered “standard risk”:
- T4 lesions
- Fewer than 12 lymph nodes examined
- Presence of bowel perforation or obstruction
- Poorly differentiated tumors,
- Lymphatic or venous invasion
These parameters are generally qualitative and are not informative for further differentiating risk in standard risk patients, who constitute the majority of stage II colon cancer. The Oncotype DX Colon Cancer Assay helps to distinguish stage II colon cancer patients at low risk of colon cancer recurrence from those who are at high risk for colon cancer recurrence.
80%-90% of recurrences after curative resection are discovered within the first two to three years. Less than 5% of colon cancer recurrences occur further out than 5 years post surgery. Recurrent disease is often asymptomatic arising in the liver and lungs, and is detected via imaging. Early detection has altered long-term prognosis for patients with resectable disease or who received prompt treatment. The Oncotype DX Colon Cancer Assay helps stage II colon cancer patients more accurately determine their risk of recurrence, which should lead to a more informed and personalized treatment plan.