Oncotype DX Validated in Stage II and III Colon Cancer
by C.H. Weaver M.D.
The Oncotype DX® Recurrence Score® (RS) results predict recurrence risk in stage II and III colon cancer and may better inform adjuvant therapy decisions in this population, according to the results of a validation study published in the Journal of Clinical Oncology.
Stage II colon cancer refers to cancer that extends through the wall of the colon but has not invaded lymph nodes or spread to distant parts of the body. Many patients with this stage of disease have good outcomes with surgery alone, and routine adjuvant (post-surgery) chemotherapy is not currently recommended for stage II colon cancer. Chemotherapy may, however, be considered for stage II patients with a higher risk of cancer recurrence.
The Oncotype DX colon cancer 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—and as a result, can improve treatment decisions. The Recurrence Score has been validated in in patients with stage II colon cancer, but this is the first study to validate it in patients with stage III disease.
In the large, independent validation study Recurrence Score was assessed in 892 fixed, paraffin-embedded tumor specimens and then analyzed by Cox regression, adjusting for stage and treatment. The results indicated that the Recurrence Score results predicted risk of recurrence, disease-free survival and overall survival in stage II and stage III colon cancer patients receiving adjuvant chemotherapy.
The results provide additional information beyond conventional risk factors, enabling better discrimination of absolute benefit of chemotherapy as a function of risk. Patients with a high Recurrence Score result can be expected to derive larger absolute chemotherapy treatment benefit than patients with a low Recurrence Score result in both stage II and stage III colon cancer.
The researchers concluded that the Recurrence Score predicts recurrence risk in stage II and stage III colon cancer. The test provides quantitative and individualized risk assessment that helps guide chemotherapy treatment decisions.
Yothers G, O’Connell MJ, Lee M, et al. Validation of the 12-Gene colon cancer Recurrence Score in NSABP C-07 as a predictor of recurrence in patients with stage II and III colon cancer treated with fluorouracil and leucovorin (FU/LV) and FU/LV plus oxaliplatin. Journal of Clinical Oncology. 2013; 31(36): 4512-4519.
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