A Closer Look at Tumor Location Analyses in Colon Cancer

Transcript:Alan P. Venook, MD: The Schrag and Lee abstracts were very timely in terms of filling in some blanks that CALGB/SWOG 80405’s analyses gave us. I’d have to admit that the Schrag abstract was one that I asked Deb Schrag to work on; I was the senior author on that abstract. When I saw our data, I thought, “First things first: is this seen in the CR database?” Deb Schrag is a fabulous investigator who knows everything about everything, and she said, “No, we’re not going to see that.” I said, “Ah, humor me.” And so she did a very wonderful analysis of the CR database from 2002 to 2012. In fact, just as you might have expected, patients with left-sided primary tumors lived twice as long as patients with right-sided primary tumors.

These are Medicare patients; it’s a different population. We don’t get information on treatment for the most part. She did do an analysis; she was able to get some cetuximab data. Although the numbers are different because it’s an elderly population, all of the data are consistent with what we saw in CALGB/SWOG 80405. It’s a confirmatory observation in a broad population-based registry. Frankly, she was very surprised, as was I, that the result was that convincing.

Michael Lee was a junior person—really the person behind it is Scott Kopetz, who’s a really superb scientist at MD Anderson. Michael Lee has now moved to the University of North Carolina. They presented, in a paper, basically, a very selected population of patients not reflective of the real world, but what they see at MD Anderson. They were able to look at different biological features, molecular features of different cancer patients, and come up with an idea of who did what and what was responsible for better or worse outcomes. It was selected; they knew what they were looking for beforehand, but they showed it. In fact, they pretty much put together a molecular package that explains what the results are. It doesn’t mean that is what they are, but it’s consistent with it. So, another very confirmatory bit of research that shows that things like amphiregulin, epiregulin, some of these co-factors, are relevant in outcome.

And then the other paper discussed was Dr. Kimmie Ng, who was the discussant who put it in perspective very well. We don’t often, in ASCO, in a colon cancer session, have three papers that put together a story. That’s cool to be able to do that, to ask and answer the question all in the same session. And that’s the collegial collaborative nature of what we can do sometimes. That’s good stuff.

Clearly, it takes a lot of us put together to figure this out. As I said, it’s humbling for most of us to realize that this has been…I’ve been doing this for a long time, and I never realized that we had two different diseases on our hands. I was asked yesterday, was I going to be a right colon cancer doctor or a left colon cancer doctor? I chose left because they do better than right. But somebody else chose right because they need more help. In any case, it’s a very amazing development that none of us saw coming.

So, the question I’m asked is, does this change what I’m going to do for my next patient? Probably not. I’ve known these data for a while. Did I change a while ago? Maybe so, but I’ve never been a big user of cetuximab first-line because most patients in the United States really don’t want the acne rash. I do believe that you need to pick and choose your patients carefully. We will probably be more aggressive in trying to get the molecular information earlier. But without question, in a patient with a right-sided tumor, I wouldn’t give cetuximab now. I haven’t done that mostly, but that would be a change. Otherwise, I don’t think it changes much of what I do. For other practitioners, it may, and other people may look at the same data and come up with different conclusions.

Transcript Edited for Clarity