Colon Cancer
*Note: Validation studies have already been performed on the 12-gene
Oncotype DX Colon Cancer Assay which is commercially available for newly
diagnosed patients with stage II colon cancer. For detailed information about Oncotype
DX, please call: (866) ONCOTYPE or visit
www.oncotypedx.com
Oncotype 12 Gene Colon Cancer Assay
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New Targets in Development:
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Mismatch Repair (MMR) Deficiency/Microsatellite Instability (MSI): Development stage
Stage II & III oxaliplatin benefit: Development stage
Targeted therapy benefit (e.g., EGFR and angiogenesis targeted drugs): Development
stage
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U.S. Incidence of Colon Cancer
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105,000/Year (All stages)1
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Global Incidence of Colon Cancer
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740,000/Year (All stages)2
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About Colon Cancer
In the Western world, colorectal cancer (including colon cancer) is the third most
common form of cancer. Mushroom-like non-cancerous growths called polyps are often
a precursor to colon cancer. Diagnosis of colon cancer is frequently made via colonoscopy.
Current colon cancer treatment includes surgery, followed in many cases by adjuvant
chemotherapy.
For stage II colon cancer (where there is no tumor involvement of the lymph nodes),
only a small percentage of these patients actually benefit from chemotherapy. Current
colon cancer treatment selection is based on an assessment of recurrence risk; however,
only a limited set of clinical and pathologic markers have been available until
now. In the absence of an accurate assessment of colon cancer recurrence, it is difficult
to identify which stage II colon cancer patients should be treated more aggressively
with chemotherapy.
About the Oncotype DX Colon Cancer Test
Genomic Health's Oncotype DX colon cancer assay is an advanced diagnostic
test that has been validated for the assessment of risk of recurrence following
surgery in stage II colon cancer patients. This multigene test examines a colon
cancer patient's tumor at a molecular level, in order to provide information about
the individual biology of each tumor. Oncotype DX does this by evaluating
12 genes within the colon tumor to determine the likelihood that the cancer cells
will spread and thus cause colon cancer recurrence following surgical resection.
The information provided by Oncotype DX has been shown to have independent
value beyond currently used measures for determining colon cancer recurrence risk.
For people recently diagnosed with Stage II colon cancer, the Oncotype
DX test may be an appropriate part of treatment planning. For detailed information
about the Oncotype DX colon cancer assay, please call: (866) ONCOTYPE or
visit www.oncotypedx.com
About Genomic Health's Colon Cancer Products in Development
Unlike in breast cancer, there are few established biomarkers in stage II colon
cancer to assess risk and guide treatment decisions. Deficiencies in DNA mismatch
repair (MMR) gene function, either due to decreased gene expression or mutation,
results in the accumulation of DNA alternations which can be manifest as abnormal
shortening or lengthening of microsatellite DNA sequences, also known as Microsatellite
Instability (MSI). Patients with MMR deficient (MMR-D) colon tumors have been shown
to have significantly lower colon cancer recurrence risk, and thus MMR testing can
be complementary to the information provided by the Oncotype DX colon cancer
assay. Genomic Health is working to facilitate the incorporation of MMR/MSI testing
into treatment planning in stage II colon cancer.
Stage II Colon Cancer - Commonly Used Adjuvant Therapies
For stage II and III colon cancer, the most commonly used adjuvant therapies involve
combinations of fluoropyrimidines and oxaliplatin. Oxaliplatin is known to produce
significant toxicities, including the potential for long-term sensory nerve damage.
As such, methods to identify the likelihood of benefit of oxaliplatin are greatly
needed to guide the optimal use of this drug. The development of newer targeted
therapies, such as cetuximab, which targets the epidermal growth factor receptor
(EGFR), and bevacizumab, which targets the vascular endothelial growth factor (VEGF),
offers promise for improved outcomes in colon cancer but will likely further increase
the complexity of treatment planning for these patients. In May 2008, Genomic Health
announced results from a study, in collaboration with Bristol-Myers Squibb (BMS)®
and Imclone®, identifying a small number of genes that could predict
response to Erbitux®. These results, suggest that quantitative expression
of a number of these identified genes used in conjunction with KRAS mutation status,
increases the ability to predict which patients might benefit from colon cancer
treatment with Erbitux over KRAS status alone. Additional studies are planned to
confirm these findings and to develop new multigene tests to guide the use of specific
treatment therapies in colon cancer.