Among patients with Stage II or Stage III colon cancer, the Oncotype DX colon cancer test provides information about risk of cancer recurrence and overall survival, and may help guide treatment decisions. These results were presented at the European Society for Medical Oncology (ESMO) 2012 Congress.
Gene expression profiling explores the patterns of genes that are active in tumor cells. Studies suggest that gene expression may provide important information about prognosis or likely response to treatment in several types of cancer. For example, among women with early-stage, estrogen receptor-positive breast cancer, the Oncotype DX breast cancer test has been shown to predict the likelihood of cancer recurrence and the likelihood of benefit from chemotherapy. As a result, the test has been added to medical guidelines for early-stage breast cancer.
A similar test became available for colon cancer patients in 2010. The test was originally developed for use in patients with Stage II colon cancer, but has now also been validated among patients with Stage III colon cancer. The test evaluates 12 genes in a sample of tumor tissue and generates a Recurrence Score. The Recurrence Score provides information about the likelihood of cancer recurrence.
To further assess the ability of the test to predict recurrence risk among patients with Stage II or Stage III colon cancer, researchers evaluated 892 patients. The patients were enrolled in a clinical trial that assessed two different approaches to adjuvant (post-surgery) chemotherapy: patients were treated with 5FU/LV alone or in combination with oxaliplatin. The addition of oxaliplatin increased effectiveness, but also increased side effects.
- The Recurrence Score provided information about the risk of cancer recurrence as well as overall survival. Higher scores were linked with worse outcomes.
- The Recurrence Score remained an important predictor of risk even after accounting for other characteristics of the cancer.
- When looking at the benefit of adding oxaliplatin, the absolute benefit (but not the relative benefit) was greater for patients with higher Recurrence Scores.
- In an exploratory analysis, the researchers identified several genes that were predictive of a benefit from oxaliplatin.
These results confirm that the Oncotype DX colon cancer test provides information about risk of recurrence among patients with Stage II and Stage III colon cancer. The test is available for patients with both stages of disease.
Reference: O’Connell M, Lee M, Lopatin M et al. The 12-gene colon cancer recurrence score (RS) predicts recurrence in stage II and III colon cancer patients treated with 5FU/LV (FU) and 5FU/LV + oxaliplatin (FU+OX): Validation in NSABP C07. Paper presented at: ESMO 2012; Vienna, Austria. Abstract 523PD.
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