DR GOLDBERG: This was a fascinating study that looked at FLOX versus 5-FU. All right. And it included both Stage II and Stage III patients.
And they did the Recurrence Score® evaluation using the Oncotype 12-gene assay on all the patients.
Now we know from previous data that’s been presented from NSABP, from QUASAR and from others that in Stage II, the Recurrence Score can discriminate between a relatively low risk of recurrence and a higher risk of recurrence, but the delta is between about 10% and 25%. There hadn’t really been much data on Stage III patients.
So there was data presented here that, in Stage III patients, the recurrence score could predict high and low risk, particularly for Stage IIIA, the 1 to 3 node-positive group. And you remember in colon cancer the relapse score is prognostic but not predictive.
But here they extended it a little bit to the potential to be predictive. Because what they showed is, in patients with a low Recurrence Score for Stage III disease, oxaliplatin didn’t add much to 5-FU. So it makes you wonder if, in some Stage III patients, you could spare the potential toxicity, the neurotoxicity, of oxaliplatin and still have a benefit to adjuvant therapy.
So to me it was a fascinating preliminary study. It’s not something that is going to really change my practice. I’m not going to start ordering Oncotype DX on my Stage III patients on the basis of this. But it suggests that this sort of approach may provide us with additional benefits.
DR LOVE: So, Alan, what’s your take on this? You presented some data looking at this Oncotype assay out of the CALGB last year. What was your thought about these new data?
DR VENOOK: I think it is interesting to extend it to Stage III, that the same Recurrence Score, in this case, applies to Stage II and Stage III. There is data from the PETACC Group from S Tejpar in Europe that there may be a different set of genes involved in Stage II versus Stage III. So this interesting. I think it isn’t something that I’m using.
I do think the issue of the oxaliplatin benefit or not is very pertinent. And, in fact, there’s a paper in JCO that’ll look at an update of MOSAIC. Now, I think 8 years later, that shows that the delta from oxaliplatin is really relatively small when push comes to shove in terms of overall survival.
So this may be an important tool if, in fact, we can learn form this who should or should not receive oxaliplatin. We don’t know that yet. But this is preliminary data that suggests that.
DR LOVE: So, Axel, this issue of prognostic versus predictive has always been brought up by the GI investigators. But, I mean, if I read that poster, the NSABP poster correctly, they’re kind of saying something that’s been said from QUASAR, which is, yes, it’s not really like breast cancer that the relative risk reduction changes, but you can kind of look at these numbers and really be able to get more information about how much absolute benefit a patient might receive from treatment.
Do you agree with that, or do you think it is purely prognostic?
DR GROTHEY: It’s actually probably the relative benefit that is the same across the different tumor groups. The problem with Oncotype DX in colon is, besides being not predictive and only prognostic, it doesn’t really spread the prognostic groups out as large as I would like them to be spread out. I mean, we’re talking about a delta between high- and low-risk groups of about a 10% absolute difference in a 3-year disease-free survival. And my gut feeling is we should do better than that.