Long-Awaited TAILORx Results 'Will Impact Your Practice'

Hi. It's Dr Kathy Miller from Indiana University. I want to give you a quick preview of what you should be looking for in the breast cancer abstracts at the American Society of Clinical Oncology (ASCO) annual meeting this year. Do not miss the Plenary Session. We have been waiting for almost 7 years for the results of the TAILORx trial. We will wait no longer.

It was about 10 years ago that we first learned about and grew comfortable with the Oncotype DX® Breast Recurrence Score assay to identify which of our patients with node-negative, ER-positive tumors really needed chemotherapy.^[1] Those with a low score really did not get any benefit. Conversely, those with a high score had huge benefit—much more than we had ever seen with chemotherapy in an ER-positive setting.

For all its power, Oncotype DX had an Achilles' heel, if you will. We had uncertainty about the benefits of chemotherapy in patients with an intermediate risk score. The point estimate for that group as a whole suggested that there was really not a benefit from chemo, but the confidence intervals included that same 2%-4% benefit that we might get from lumping everybody together. Thus, this was purpose of the TAILORx trial.

TAILORx^[2] took patients with mid-range scores and randomized them to hormone therapy alone or hormone therapy with chemo to really tell us whether there is a benefit with chemo, and how much of a benefit. And hopefully can we get further nuanced as to who derives that benefit.

This trial enrolled almost 10,000 patients in aggregate. It shifted the boundaries of intermediate risk from the standard assay's cut points of 18 and 31; the trial used cut points of 11 and 25. This was done for two reasons. First, there was greater fear of undertreatment. Could we potentially lose the benefits we had lost by lumping everybody together if we selected patients for hormone therapy alone who really needed chemo? Also, pragmatically, the trial needed to randomize about 4500 patients in order to answer this question with only about a quarter of the patients in the intermediate-risk group by the original cut point. That was going to be difficult. By shifting the cut point, we estimated that about half of the patients would be in that group.

There will be lots of other news from the breast cancer session, but this is the one you want to make sure you get to. I am told by my colleague and the trial’s principal Investigator, Dr Joe Sparano, that the manuscript will be published concurrently with the presentation. That will allow us to get into more details than the short presentation will allow. Regardless of the results, this abstract is going to impact your practice. You are going to want to make sure you see it. I hope to see you there.