Genomic Health, Inc. has announced presentation of three studies at the American Society of Clinical Oncology® (ASCO®) (1) Gastrointestinal (GI) Cancer Symposium, including one finding that high tumor grade was not a marker of higher recurrence risk in stage II colon cancer, suggesting that other markers, such as the Oncotype DX® Recurrence Score® (RS) test as well as T-stage and mismatch repair (MMR) status, should be considered by physicians during the treatment decision-making process.
"These results presented at ASCO-GI reinforce the value that the Oncotype DX Colon Cancer test provides to physicians, patients and payors," said Steven Shak, M.D., chief medical officer of Genomic Health. "The Oncotype DX Colon Cancer test, which has been commercially available for the past year, combines the practicality of paraffin-embedded tumor tissue with robust evidence from multiple large independent development and validation studies focused on the specific clinical questions relevant to physicians and patients. Rigorous comparison of the colon cancer test with conventional markers of recurrence risk, including MMR and T-stage, has demonstrated its independent value. These data allow physicians and patients to confidently and appropriately incorporate information about individual tumor biology provided by Oncotype DX into treatment decisions in stage II colon cancer. As with our breast cancer program, we are committed to increasing the clinical utility of our colon cancer franchise through continued research and look forward to expanding the Oncotype DX service by offering MMR testing this year."
Comparative Study Supports Independent Determination of MMR Status by IHC
Previous research suggests that stage II colon cancer patients with deficient mismatch repair (MMR-D) have significantly fewer recurrences and may respond less well to fluorouracil-based chemotherapy. It is recommended that immunohistochemical (IHC) determination of MMR status be considered to identify patients for whom adjuvant chemotherapy is not indicated, but little was known regarding the variability of such assay results.
Results from this comparative study demonstrate that determination of MMR status by IHC in two different laboratories is associated with excellent inter-assay agreement. The study, "Assay result variability during determination of mismatch repair deficiency status using immunohistochemistry: A transatlantic comparative study" (G. Hutchins et al, Abstract #403), will be presented in a poster on Saturday, January 22.
High Tumor Grade Not Found to Be a Marker of High Recurrence Risk in Stage II Colon Cancer
High tumor grade is often considered a marker of higher recurrence risk in stage II colon cancer. However, multiple large recently reported studies have found that high tumor grade, at least in stage II colon cancer, was not associated with higher recurrence risk. In addition, multiple different systems for tumor grading are used in clinical practice. Results from this study confirmed that high tumor grade, as assessed by two pathologists with expertise in colon cancer, does not predict higher recurrence risk in stage II colon cancer patients and that inter-pathologist agreement on colon tumor grade is modest to moderate, even with central expert review.
The investigators concluded that the standardized colon cancer Recurrence Score assay, MMR, and T-stage should be used in the assessment of stage II patients. The study, "Reproducibility of colon tumor grade and relationship to recurrence in the context of clinical, pathologic, and genomic tumor features in 504 patients with stage II colon cancer treated with surgery alone at the Cleveland Clinic" (I. C. Lavery et al, Abstract #526), will be presented in a poster on Saturday, January 22.
Impact of Onco type DX Test on Quality-Adjusted Life Expectancy and Costs in Patients with Stage II Colon Cancer
In an independent study led by authors Neal Meropol, University Hospital Seidman Cancer Center and Case Western Research University; Gary Lyman, Duke University; and Rebecca Chien and John Hornberger, Cedar Associates, results showed that clinical use of the Oncotype DX Recurrence Score to assess risk of recurrence in T3 stage II colon cancers with intact mismatch repair (MMR-P) is likely to improve quality-adjusted life expectancy and be cost-saving from a societal perspective.
Patient age and adverse effects associated with chemotherapy are important considerations in adjuvant treatment decisions. The study, "Use of a multigene prognostic assay for selection of adjuvant chemotherapy in patients with stage II colon cancer: Impact on quality-adjusted life expectancy and costs" (N. J. Meropol et al, Abstract #491), will be presented in a poster on Saturday, January 22.
"Our data support the notion that use of a genomic test like the Recurrence Score Assay may potentially reduce chemotherapy use, improve quality adjusted survival, and save health care costs," said Neal J. Meropol, M.D., Chief of the Division of Hematology and Oncology at University Hospitals Seidman Cancer Center and Case Western Reserve University.
Genomic Health and TGen Publish Laboratory Study Identifying Genes that May Impact Effectiveness of Oxaliplatin
Separately, Genomic Health and the Translational Genomics Research Institute published a laboratory study in Molecular Cancer Research that describes the identification of 27 genes that, when silenced, altered the sensitivity of colon tumor cells to the drug oxaliplatin. Oxaliplatin is widely used in colon cancer; however a significant number of patients experience serious side effects. This discovery is an important advance in efforts by Genomic Health and its collaborators to develop a genomic test that could help physicians better target the use of oxaliplatin in colon cancer patients and highlights the company's commitment to conducting ongoing clinical research in this area.