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Jean,
The answer to your question is that the OncotypeDX test is giving fairly valid indications only for low & high Recurrence Scores leaving 40 to 60% of patients with intermediate scores in limbo as to whether or not they need chemo in addition to hormonal treatment:
"Dr. Sparano: We have demonstrated that for some patients -- for example, those with very low or very high Recurrence Scores with OncotypeDX -- we can be fairly confident making recommendations regarding treatment. For those who have a low Recurrence Score, for instance, we can recommend hormonal therapy alone with great confidence because we know those patients have a very low risk of relapse with hormonal therapy alone and will be unlikely to benefit from chemotherapy. We also know that for patients who have a very high Recurrence Score, adding chemotherapy is associated with a substantial reduction in the risk of relapse. However, in patients who have a mid-range score, which can account for anywhere from 40% to 60% of all patients tested, the score is not necessarily informative because we do not know for sure whether chemotherapy will be useful in reducing the risk of recurrence in that group. This is the question that the TAILORx [Trial Assigning Individualized Options for Treatment] trial is designed to define.
Other issues include whether we can use these assays to make treatment decisions in patients with lymph-node-positive breast cancer, and in HER-2-positive or ER-negative breast cancer, and that work is now ongoing".
More research will be needed to find pronostic markers which will help almost all categories of patients in selecting their optimal treatment.
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